How Many Covid Boosters Are There? - 2024, CLT Livre

How Many Covid Boosters Are There?

What is the newest COVID booster?

New COVID-19 vaccines are now available to a public that is sick of COVID-19. Doctors want people to get them anyway. The arrival of another round of COVID-19 vaccines this week offers more protection for a population that is weary of the disease and has built up some immunity, but that remains vulnerable to new variants that are taking hold.

The Food and Drug Administration (FDA) approved the boosters by Moderna and Pfizer-BioNTech on Monday, and the Centers for Disease Control and Prevention’s (CDC’s) Advisory Committee on Immunization Practices followed up on Tuesday with a recommendation that they be given to anyone six months of age or older.

The vaccines are designed to protect against the latest variants of the SARS-CoV-2 virus, which causes the disease. The recommendation comes as COVID-19 cases, hospitalizations, and deaths are increasing, but remain far below the levels that the country experienced through most of the pandemic.

“We don’t want to live like we’re in a pandemic, but we want to be aware of what’s going on,” said committee member Wilbur Chen, MD, MS, professor of medicine at the Center for Vaccine Development and Global Health at the University of Maryland School of Medicine. “Our hospitals are not overwhelmed, but people are dying daily.” Below, academic researchers answer key questions that doctors and patients have about the vaccines.

Oh, please: Another COVID-19 shot? People are emotionally done with COVID-19 and are confused by never-ending reports about new variants with unpronounceable names. But experts say several continuing developments are behind the push for another round of inoculation against COVID-19.

  1. First, COVID-19 remains one of the most powerful respiratory illnesses in the country.
  2. Although the United States declared the pandemic over last May, the numbers of severe cases have been slowly growing in recent months.
  3. Hospitalization rates have increased in all age groups since mid-July,” and those rates are “far higher” than the rates for influenza, Fiona Havers, MD, MHS, commander of the Coronavirus and Other Respiratory Viruses Division of the U.S.

Public Health Service, told the advisory committee on Tuesday. Hospitalization rates for COVID-19 rose from 1.95 per 100,000 people in the week ending July 8 to 5.68 in the week ending Sept.2, according to the CDC, During most weeks since mid-July, 500 to 600 people have died from COVID-19, the agency reports.

  • Still, those figures remain low compared with the peaks of the pandemic, when 2,000 to 3,000 people were dying from the disease each week.
  • The majority of the U.S.
  • Population has some immunity” due to previous inoculations or infection, CDC epidemiologist Megan Wallace, DrPH, told the committee.
  • But “new variants have emerged” and “hospital admissions are likely to increase this winter.” Second, the new variants might circumvent immunity that had been gained through previous inoculations and infections.

“The virus is changing over time, forcing us to stay on our toes in terms of whether we’re adequately protected from new variants,” Amanda Simanek, PhD, MPH, associate professor in the Department of Foundational Sciences and Humanities in the Chicago Medical School at Rosalind Franklin University of Medicine and Science, said in an interview.

“If the next time our body encounters that virus, if it looks different than the other time, we’re not as well equipped to respond to it.” Third, she and Chen noted that the immune response from previous inoculations and infections wanes over time. “If you want to get maximum protection for yourself or the people around you, then you would lose that protection” without another vaccination, Chen said in an interview.

How do the new vaccines differ from the previous ones? The new vaccines are designed specifically to protect against one of the newer strains of the virus: the XBB.1.5 version of Omicron, which was the dominant subvariant in June, when the FDA selected a strain to target this fall.

The process is somewhat similar to how the makeup of flu vaccines change every year according to the prevalence of certain strains (although SARS-CoV-2 has not fallen into a season pattern like the flu). “You can’t get a flu vaccine once in your life” and be protected from the flu forever, Simanek noted, because of changes to the virus and which strains circulate at different times.

The two newly approved vaccines are the first COVID-19 vaccines in the United States that do not target the original virus. “The original virus basically doesn’t circulate anymore,” said Simanek, who writes about the virus and other matters for Those Nerdy Girls, a group of researchers and clinicians who aim to provide trusted health information.

Both newly approved vaccines were developed with messenger RNA (mRNA) technology, The FDA and the CDC are considering another vaccine, made by Novavax, that is not developed with mRNA. That vaccine contains the spike protein of the original virus and also targets strains related to XBB. “There’s a lot of interest in having non-mRNA vaccines available,” Demetre Daskalakis, MD, director of the Division of HIV/AIDS Prevention in the National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, told the committee.

If other strains become predominant, can these vaccines protect against those? Various subvariants have been emerging, including those designated BA.2.86 and EG.5, and might become dominant in the United States, CDC researchers told the committee. Natalie Thornburg, PhD, lead research microbiologist at the CDC, noted that those subvariants are basically on the XBB family tree.

  1. There’s a lot of viral diversity” among variants of SARS-CoV-2, but “almost all circulating are in the XBB lineage,” Thornburg said.
  2. That means vaccines designed to protect against XBB are likely to protect against variants that are related to it.
  3. Moderna, Pfizer, and Novavax told the CDC that their tests show that the new vaccines generate strong antibody response to, and therefore at least some protection against, emerging strains.

“There have been a number of study results that are giving us confidence that this monovalent updated vaccine is going to effectively neutralize the emerging variants that are now coming online,” Simanek said. What does “protection” mean? Ideally, the vaccines will prevent someone from getting infected, but study data indicate that their primary benefit is protecting infected people from severe illness.

“What we should expect from these vaccines is that they protect you against hospitalization and severe complications, and even death,” Chen said. When will the vaccines be available and at what cost? Moderna and Pfizer told the committee they will get supplies to some hospitals, doctors’ offices, and pharmacies within a day or two of Tuesday’s CDC recommendation.

It is expected that most health insurance policies will cover the cost of the vaccines, Georgina Peacock, MD, director of the Immunization Services Division at the CDC, told the committee. Medicare does cover them without a cost to beneficiaries. The CDC oversees a Bridge Access Program to provide free vaccinations to those who don’t have insurance to cover it.

  1. The goal is no-cost, timely access for all,” Peacock told the committee.
  2. Who does the CDC say should get the shots? Are certain populations deemed to be priority? Everyone age six months and up is eligible.
  3. Just like with influenza, we should vaccinate everyone,” Chen said.
  4. The people who will get the highest benefit are probably going to be older adults and the immune-compromised.

I think we have plenty of vaccine, so we felt confident about making a universal recommendation.” When should people get these vaccines? Should they combine them with vaccines for the flu and RSV? The answer depends on the patient’s circumstances; they should consult their doctors if they are unsure.

  1. The factors include a person’s vulnerability to each disease, past side-effect responses to the COVID-19 and flu vaccines, and efficiency.
  2. COVID-19 and respiratory syncytial virus (RSV) are circulating now, so it makes sense for vulnerable populations to get at least one or both of those inoculations as soon as possible.

(RSV is recommended for anyone 60 and over.) Simanek said people might choose to wait until October for the flu shot, so as to extend their protection through the typical flu season peak of December through February. All things being equal, Chen prefers that people get all vaccinations for which they are eligible at the same time, rather than trying to complete multiple inoculation appointments.

  1. We’re trying to make sure these visits are efficient from the point of view of the patient and do not result in a missed opportunity,” he said.
  2. People who have fall and winter plans for traveling and for gathering with friends and family for holidays should get the vaccines in time to protect themselves and others from infection, Chen noted.

He pointed out that immunity typically grows over one or two weeks after inoculation, so people should take that timing into account. If someone recently had COVID-19 or recently got the previous booster, when should they get this vaccine? People should wait about two months from their most recent dose and about three months after infection in order to maximize their protection, experts told the CDC.

Here’s why, Simanek said: “Your body will benefit from immune protection against the virus for a while” after inoculation or infection. “You might as well ride out that period of immune protection and prolong” protection by getting the vaccine a few months later. Does it matter if a patient did or did not get the previous vaccines and boosters? Maybe, depending on factors such as which shots someone got and their age.

For example, people who have had no inoculations against COVID-19 might need two rounds of one of the new inoculations, according to manufacturer presentations to the CDC. Patients should ask their doctors or pharmacists for specific guidance. Bottom line: What can doctors tell patients about getting the new vaccines? Chen said he will recommend that patients get the new vaccines “but I’m not going to be iron-fisted about it.” His advice to patients: “You could potentially protect more of the people around you from getting the infection and maybe getting hospitalized.” Simanek concurs: “The more people who uptake the vaccine, the less transmission we’re likely to have and the more protection we have as a community.”

Are Pfizer and Moderna no longer authorized?

FDA Takes Action on Updated mRNA COVID-19 Vaccines to Better Protect Against Currently Circulating Variants For Immediate Release: September 11, 2023 Today, the U.S. Food and Drug Administration took action approving and authorizing for emergency use updated COVID-19 vaccines formulated to more closely target currently circulating variants and to provide better protection against serious consequences of COVID-19, including hospitalization and death.

Individuals 5 years of age and older regardless of previous vaccination are eligible to receive a single dose of an updated mRNA COVID-19 vaccine at least 2 months since the last dose of any COVID-19 vaccine. Individuals 6 months through 4 years of age who have previously been vaccinated against COVID-19 are eligible to receive one or two doses of an updated mRNA COVID-19 vaccine (timing and number of doses to administer depends on the previous COVID-19 vaccine received). Unvaccinated individuals 6 months through 4 years of age are eligible to receive three doses of the updated authorized Pfizer-BioNTech COVID-19 Vaccine or two doses of the updated authorized Moderna COVID-19 Vaccine. The FDA is confident in the safety and effectiveness of these updated vaccines and the agency’s benefit-risk assessment demonstrates that the benefits of these vaccines for individuals 6 months of age and older outweigh their risks. Individuals who receive an updated mRNA COVID-19 vaccine may experience similar side effects as those reported by individuals who previously received mRNA COVID-19 vaccines as described in the respective prescribing information or fact sheets. The updated vaccines are expected to provide good protection against COVID-19 from the currently circulating variants. Barring the emergence of a markedly more virulent variant, the FDA anticipates that the composition of COVID-19 vaccines may need to be updated annually, as is done for the seasonal influenza vaccine. The U.S. Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices will meet tomorrow (Sept.12), to discuss clinical recommendations on who should receive an updated vaccine, as well as further considerations for specific populations such as immunocompromised and older individuals. Manufacturers have publicly announced that the updated vaccines would be ready this fall, and the FDA anticipates that the updated vaccines will be available in the near future.

“Vaccination remains critical to public health and continued protection against serious consequences of COVID-19, including hospitalization and death,” said Peter Marks, M.D., Ph.D., director of the FDA’s Center for Biologics Evaluation and Research.

“The public can be assured that these updated vaccines have met the agency’s rigorous scientific standards for safety, effectiveness, and manufacturing quality. We very much encourage those who are eligible to consider getting vaccinated.” The updated mRNA vaccines are each approved for individuals 12 years of age and older and are authorized under emergency use for individuals 6 months through 11 years of age.

As part of today’s actions, the bivalent Moderna and Pfizer-BioNTech COVID-19 vaccines are no longer authorized for use in the United States. Data Supporting the Updated mRNA COVID-19 Vaccines (2023-2024 Formula) The mRNA COVID-19 vaccines approved and authorized today are supported by the FDA’s evaluation of manufacturing data to support the change to the 2023-2024 formula and non-clinical immune response data on the updated formulations including the XBB.1.5 component.

The updated mRNA vaccines are manufactured using a similar process as previous formulations. In studies that have been recently conducted, the extent of neutralization observed by the updated vaccines against currently circulating viral variants causing COVID-19, including EG.5 and BA.2.86, appears to be of a similar magnitude to the extent of neutralization observed with prior versions of the vaccines against corresponding prior variants against which they had been developed to provide protection. This suggests that the vaccines are a good match for protecting against the currently circulating COVID-19 variants. The benefit-risk profile of previously authorized and approved mRNA COVID-19 vaccines is well understood as these vaccines have been administered to hundreds of millions of people in the United States.

Based on an evaluation of the totality of the evidence, the benefit-risk profile is favorable for individuals 6 months of age and older to receive an updated COVID-19 mRNA vaccine. Although serious outcomes from COVID-19 are less common in younger individuals, they do occur, and it has been demonstrated that recently receiving a COVID-19 vaccine reduces the risk of such serious outcomes.

Approval of Comirnaty (COVID-19 Vaccine, mRNA) to include the 2023-2024 formula, and a change to a single dose for individuals 12 years of age and older. Comirnaty was previously approved as a two-dose series for individuals 12 years of age and older. Approval of Spikevax (COVID-19 Vaccine, mRNA) to include the 2023-2024 formula, a change to a single dose for individuals 18 years of age and older, and approval of a single dose for individuals 12 through 17 years of age. Spikevax was previously approved as a two-dose series for individuals 18 years of age and older. Authorization of Moderna COVID-19 Vaccine for emergency use in individuals 6 months through 11 years of age to include the 2023-2024 formula and lower the age eligibility for receipt of a single dose from 6 years to 5 years of age. Additional doses are also authorized for certain immunocompromised individuals ages 6 months through 11 years, as described in the fact sheets. Authorization of Pfizer-BioNTech COVID-19 Vaccine for emergency use in individuals 6 months through 11 years of age to include the 2023-2024 formula. Additional doses are also authorized for certain immunocompromised individuals ages 6 months through 11 years, as described in the fact sheets.

The approval of Comirnaty (COVID-19 Vaccine, mRNA) (2023-2024 Formula) was granted to BioNTech Manufacturing GmbH. The EUA amendment for the Pfizer-BioNTech COVID-19 Vaccine (2023-2024 Formula) was issued to Pfizer Inc. The approval of Spikevax (COVID-19 Vaccine, mRNA) (2023-2024 Formula) was granted to ModernaTX Inc.

Should i get Moderna or Pfizer new vaccine?

News: Moderna vs. Pfizer: Is There a “Best”. (The Scientist) – Behind the headlines – NLM September 24, 2021 Both of the mRNA vaccines available in the US are highly effective against severe COVID-19, but recent studies suggest that Moderna’s elicits a stronger immune response and might be better at preventing breakthrough infections. at The Scientist AUGUST 20, 2021 H Chung et al Two doses of mRNA covid-19 vaccines were observed to be highly effective against symptomatic infection and severe outcomes. Vaccine effectiveness of one dose was observed JULY 22, 2021 KA Earle et al A correlate of protection (CoP) is urgently needed to expedite development of additional COVID-19 vaccines to meet unprecedented global demand.

To assess whether antibody AUGUST 30, 2021 D Steensels et al This study compares the immune responses to the BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna) COVID-19 vaccines in health care workers in Belgium. SEPTEMBER 1, 2021 NE Richards et al This cohort study compares antibody responses in a cohort in which both BNT162b2 and mRNA-1273 COVID-19 vaccines were administered.

JANUARY 1, 2021 JJ Broseta et al Immunization with mRNA vaccines generated a humoral and cellular immune response in a high proportion of patients with kidney failure receiving maintenance dialysis. Thes AUGUST 18, 2021 AT Strauss et al Prior studies have demonstrated a decreased humoral response in solid organ transplant recipients (SOTRs) to SARS‐CoV‐2 mRNA vaccination (17% antibody response after dose SEPTEMBER 14, 2021 J Mateus et al,

What is bivalent booster?

6. How is this COVID booster different from the previous one? – It’s not. These boosters are the same as the bivalent boosters first offered last fall. As with the previous boosters, these are mRNA vaccines, offered by Pfizer-BioNTech and Moderna, that target two virus strains: the original SARS-CoV-2 and Omicron subvariants BA.4 and BA.5.

What is the best COVID booster?

Adults and kids ages 6 months and older can get either an updated Pfizer or Moderna vaccine. The CDC recommends either of these vaccines for boosters. They don’t prefer one over the other. However, for kids younger than 5 years old, the choice usually depends on the primary vaccine series they initially received.

Is it ok to get Pfizer booster after Moderna?

If you received a Johnson & Johnson vaccine, you are eligible to receive a Pfizer or Moderna booster shot. Or, if your first two doses were with the Moderna vaccine, you can receive a Pfizer vaccine.

How effective is the COVID booster after 6 months?

Discussion – We showed that the decline in vaccine efficacy or effectiveness against severe COVID-19 disease with time since vaccination was less than that for SARS-CoV-2 infection and symptomatic COVID-19 disease. In most studies, the vaccine efficacy or effectiveness against severe disease remained high (≥70%) for up to 6 months after vaccination for all four vaccines that we evaluated (and mostly ≥80% for the two mRNA vaccines).

  • Nonetheless, by 6 months there was a drop in vaccine efficacy or effectiveness for severe disease of a mean of 9·5–10·0 percentage points, including among older people.
  • This smaller decrease in vaccine efficacy or effectiveness for severe disease is reassuring given that prevention of severe disease and death remains the primary objective of COVID-19 vaccination.
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By contrast, most studies showed a notable decrease in vaccine efficacy or effectiveness by 6 months after vaccination for SARS-CoV-2 infection (a decrease of 21 percentage points) and all symptomatic COVID-19 disease (a decrease of 25–32 percentage points).

  1. However, the data were heterogenous, with some studies showing minimal decrease in vaccine efficacy or effectiveness over time and others showing substantial decrease (ie, ≥25 percentage points).
  2. A decrease in the vaccine efficacy or effectiveness over time has three potential explanations: the decrease can reflect lower vaccine efficacy or effectiveness against a new variant; true waning immunity caused by loss of vaccine-induced immunological protection; or bias.

We showed that vaccine efficacy or effectiveness decreased over time when restricting analysis to a single variant. This finding was reinforced by our second analysis of breakthrough infections with the delta variant that showed higher breakthrough risk with longer times since vaccination.

Together these findings suggest that the decrease in vaccine efficacy or effectiveness over time was likely not caused, for the most part, by the temporal increase in prevalence of the delta variant. Waning vaccine efficacy or effectiveness is a plausible explanation for the decrease in vaccine efficacy or effectiveness against infection and disease.

The finding is consistent with immunological data showing that over time, amounts of most vaccine-derived antibodies, including those that neutralise the virus, decline.39, 40 Yet, because the immune system forms memory cells that can be activated upon exposure to a virus and includes cellular immunity, it is not clear whether this observed antibody decay results in diminished vaccine efficacy or effectiveness, and if so, over what timeframe and against which outcomes.

Nevertheless, further support for possible waning immunity comes from evidence showing that after giving a booster dose the vaccine efficacy or effectiveness increases compared with people who had only received the primary vaccine series.41, 42 Moreover, it has been shown that with increasing time since full vaccination, the viral load of breakthrough infections increases, but becomes lower again soon after booster vaccination.43 We did not see an obvious difference in the magnitude or timing of decrease in vaccine efficacy or effectiveness between people of all ages and older people in the meta-regression, although the number of studies was probably too low to make definitive conclusions.

A study from the UK showed that decreases in vaccine efficacy or effectiveness seemed to occur more among clinically extremely vulnerable older people.25 Although waning immunity is consistent with the data, we cannot exclude the possibility that the observed decrease in vaccine efficacy or effectiveness over time was caused, either partly or wholly, by biases.

  1. An underlying assumption of observational studies is that people who are unvaccinated should be at the same risk of exposure to SARS-CoV-2 as those who are vaccinated in the same population.
  2. At high vaccine coverage, this assumption might no longer apply, given that people who remain unvaccinated either choose to remain unvaccinated or are unable to get vaccinated for reasons that might be associated with a differential risk of COVID-19 compared with the general population.30, 44, 45, 46 Although some differences can be identified and adjusted for in the analysis (eg, age and demographic group), others might be less obvious, harder to measure and adjust for, and could lead to underestimation of true vaccine efficacy or effectiveness over time (eg, clinically extremely vulnerable status).25 The expected bias based on the magnitude and direction of the differential risk of COVID-19 among people who are unvaccinated showed that confounding is more important when the true vaccine efficacy or effectiveness is not as high ( appendix p 17 ); this finding implies that confounding by risk among the unvaccinated group is accentuated when the vaccine has lower initial efficacy and when the true vaccine effectiveness has become lower over time.

Several other potential biases in assessing the duration of vaccine efficacy or effectiveness over time can occur. Some important biases that could result in an overestimation of decreases in vaccine efficacy or effectiveness over time are as follows: the people who are vaccinated the earliest are at sustained increased risk of infection compared with those who were vaccinated later; people who are vaccinated change their behaviour and testing frequency over time increasing the likelihood of being infected or being detected as infected, particularly with increased mobility for those who can show vaccination status; and people who remain unvaccinated have increased infection-derived immunity leading to spurious interpretations of reductions in vaccine efficacy or effectiveness as waning protection.47 Because most of these biases are unmeasured, we cannot definitely establish which ones most affected the studies included in this analysis.

  1. Our systematic review had several other potential limitations.
  2. First, given the rapid pace and multiple preprint publishing options for COVID-19-related content, it is possible that additional studies on vaccine duration of protection were not captured by our search strategy, and new studies will become available after our cutoff date.

Second, many preprint studies included in this analysis could have their data changed in the eventual publication. Third, insufficient studies met our inclusion criteria to allow for meaningful comparisons between different vaccine platforms. Fourth, a small number of vaccines were evaluated, and from few geographical settings, which might not be represen-tative of other settings with different epidemiological conditions in which duration of vaccine protection might differ (eg, more or less previous infection).

Fifth, few studies evaluated vaccine efficacy or effectiveness separately in younger people; the three studies that did so showed similar patterns of decrease in vaccine efficacy or effectiveness over time to that seen in adults of all ages and older people ( appendix p 18 ). Sixth, no heterologous schedules were evaluated.

Seventh, all included studies were published before the emergence and spread of the omicron variant. Lastly, we based our calculations on published or derived estimates of vaccine efficacy or effectiveness and their SEs rather than original person-level event data.

  1. One manifestation of this limitation is the necessity to introduce small adjustments to vaccine efficacy or effectiveness estimates of 100% to include these estimates in our model for the log-transformed relative-risk estimates.
  2. The potential bias in the summary vaccine efficacy or effectiveness estimates is small because there were only three vaccine effectiveness estimates of 100%, and two had wide CIs, which decreases their contribution in the regression model.

Further follow-up of vaccine efficacy or effectiveness against severe disease, the outcome that drives most COVID-19 policy decisions, for all vaccines beyond 6 months is needed to clarify how much more waning of protection might occur with longer duration since full vaccination.48 Continuing to produce reliable and vaccine-specific vaccine efficacy or effectiveness estimates over extended periods of time after vaccination against multiple outcomes, and in the setting of emerging variants against which vaccine efficacy or effectiveness might be lower and waning occurs faster, such as the omicron variant, is crucial for COVID-19 vaccine policy and decision-making bodies.49 Policy makers considering the use and timing of booster doses should integrate vaccine-specific and outcome-specific evidence of decreasing vaccine efficacy or effectiveness with other considerations, such as vaccine coverage and supply, prioritisation relative to primary-series vaccination, programmatic issues, and local COVID-19 epidemiology.

How long are you immune after COVID?

Share on Pinterest Research shows that the antibodies that develop from COVID-19 remain in the body for at least 8 months. Getty Images

Immunity can occur naturally after developing COVID-19, from getting the COVID-19 vaccination, or from a combination of both. In June 2022, the CDC reported that BA.4 and BA.5 subvariants of Omicron became the predominant subvariants in the U.S. Infections with variants before Omicron or being fully vaccinated appear to be less effective at preventing immunity against BA.4 and BA.5. Scientists are learning more and more about the length of immunity after developing COVID-19, getting the vaccine, or both.

Whether you’ve recovered from COVID-19, received the vaccine, or both, understanding immunity and how long it lasts can help give you important insight into how you can interact safely with others during the pandemic. First, it helps to know what immunity means. There are a few types of immunity: natural, vaccine-induced, and hybrid.

How long does it take for booster to be effective?

How long does it take for my booster to start working? Your body’s immune response kicks in almost immediately after a booster dose. It may take around two weeks to reach maximum protection.

Which vaccines Cannot be given together?

Administering Vaccines
General Issues
Note: Specific information about the administration of most vaccines is included in the Ask the Experts set for that vaccine.
I was recently told by a colleague that pregnant healthcare personnel were not to administer live vaccines to others. I had never heard that in school or practice. Is that true?
This is not true. Pregnant healthcare personnel may administer any vaccine except the ACAM2000 smallpox vaccine.
Is it acceptable to administer vaccines in the nurses’ station where vital signs and other patient care is performed?
Yes. Vaccines can be administered in a patient care area. The recommendation from CDC’s safe injection practices experts is that storing and preparing vaccines should not be done in the same area where patient care is conducted. These activities should be done in a separate area.
What is the appropriate anatomic site and needle length for intramuscular and subcutaneous vaccine injection?
Appropriate site and needle length depends on age, route of injection, and body mass. Most injected vaccines are administered by the intramuscular route.
Please refer for details to the handouts on administering intramuscular and subcutaneous vaccines to children and adults at and to adults only at,
A summary of needle length and site selection by age is below.
For intramuscular injections (use a 22- to 25-gauge needle for all ages):
For neonates (first 28 days of life) and preterm infants the anterolateral thigh should be used. A ⅝-inch needle usually is adequate to penetrate the thigh muscle if the skin is stretched flat between the thumb and forefinger and the needle is inserted at a 90-degree angle to the skin.
The anterolateral thigh is preferred for infants younger than age 12 months. For the majority of infants a 1-inch needle is sufficient.
For toddlers age 12 months through 2 years the anterolateral thigh muscle is preferred. The needle should be at least 1 inch long. The deltoid muscle can be used if the muscle mass is adequate.
For children age 3 through 10 years, the deltoid muscle is preferred; the needle length for deltoid site injections can range from ⅝ to 1 inch on the basis of technique. The anterolateral thigh can also be used. In this case the needle length should be 1 inch to 1.25 inches.
For adolescents 11 through 18 years, the deltoid muscle is preferred. The anterolateral thigh can also be used. For injection into the anterolateral thigh, most adolescents will require a 1-1.5-inch needle.
For adults age 19 years and older, the deltoid muscle is preferred. The anterolateral thigh also can be used.


For men and women who weigh less than 130 pounds (less than 60 kg), a ⅝-inch needle is sufficient to ensure intramuscular injection in the deltoid muscle if the injection is made at a 90-degree angle and the tissue is not bunched.
For men and women who weigh 130152 pounds (6070 kg), a 1-inch needle is sufficient.
For women who weigh 152200 pounds (7090 kg) and men who weigh 152260 pounds (70118 kg), a 1- to 1½-inch needle is recommended.
For women who weigh more than 200 pounds (more than 90 kg) or men who weigh more than 260 pounds (more than 118 kg), a 1½-inch needle is recommended.

/td> For subcutaneous injections (use a 23- to 25-gauge needle for all ages): Subcutaneous injections are administered at a 45-degree angle, usually into the thigh for infants younger than age 12 months and in the upper-outer triceps area of people age 12 months and older. Subcutaneous injections may be administered into the upper-outer triceps area of an infant if necessary. A ⅝-inch needle length should be used for all ages. More information on injection technique is in the ACIP “General Best Practices Guidelines for Immunization”, available at, Why are some vaccinations given subcutaneously (SC) while others must be given intramuscularly (IM)? In general, vaccines containing adjuvants (a component that enhances the antigenic response) are administered IM to avoid irritation, induration, skin discoloration, inflammation, and granuloma formation if injected into subcutaneous tissue. This includes most of the inactivated vaccines, with a few exceptions (such as IPV and pneumococcal polysaccharide vaccines, which may be given either SC or IM). Vaccine efficacy may also be reduced if not given by the recommended route. A 5 year old came in today for her preschool vaccines. She needed MMR and varicella. She has a broken arm which is in a cast. Can the anterolateral thigh be used to administer a subcutaneous vaccine in a 5 year old? Yes. There is no age limit for use of the anterolateral thigh for either subcutaneous or intramuscular vaccines. I have a 2-month-old child with a cast for hip dysplasia that completely covers the entire anterolateral thigh on both legs. She is not due to have it removed for 10 weeks. What options do we have for her injectable vaccines? Ideally, you can arrange to have the cast cut to administer vaccines in the anterolateral thighs. If that option is not available, the gluteal region can be used if not covered by the cast. There are no other sites we recommend for vaccination; however, the inactivated polio vaccine could be given subcutaneously in either arm, if the child is large enough. Rotavirus vaccine is given orally and should be administered. If vaccines cannot be given for the 10 weeks, please advise the family to keep people with any illness away from the child until she has been vaccinated. More information see ACIP’s “General Best Practices Guidelines for Immunization”, available at, I need information about the administration of vaccines to 3-month-old conjoined twins (joined at the buttocks). For their routine immunization, do we provide one set of vaccinations or two, given that they are conjoined at the buttock but share no major organs? ACIP does not address this issue. However, CDC recommends that these children should each be vaccinated, notwithstanding they are conjoined. We believe even in conjoined twins who share organs and/or blood supply, vaccination of each child would also be indicated. The rationale is one cannot be sure, even in the latter case, that the common organs/blood supply would eliminate vaccine antigens less quickly, or the immune system(s) would respond adequately, to one dose of each vaccine for the two children. Therefore two doses seems appropriate, that is, one dose of each vaccine for each child. If I need to give more than 1 injection in a muscle, are certain vaccines best given at different anatomic sites? Since DTaP and pneumococcal conjugate (PCV) are the vaccines most likely to cause a local reaction, it is prudent to give DTaP and PCV in separate limbs (if possible), so there is no confusion about which vaccine caused the reaction. How many vaccines can be given during an office visit? With rare exceptions*, all vaccines can be administered at the same visit. There is no upper limit for the number of vaccines that can be administered during one visit. ACIP and AAP consistently recommend that all needed vaccines be administered during an office visit. Vaccination should not be deferred because multiple vaccines are needed. All live vaccines (MMR, varicella, live attenuated influenza, yellow fever, and oral typhoid) can be given at the same visit if indicated. If live vaccines are not administered during the same visit, they should be separated by 4 weeks or more. When giving several injections at a single visit, separate IM vaccines by at least 1 inch in the body of the muscle if possible to reduce the likelihood of local reactions overlapping. Here are some helpful site maps for different ages so you can record where shots were given: For infants and toddlers: For older children: For adults: For details see ACIP’s “General Best Practices Guidelines for Immunization”, available at, *There are 3 exceptions to this general rule: 1) if both pneumococcal conjugate vaccine (PCV13, Prevnar 13, Pfizer) and pneumococcal polysaccharide vaccine (PPSV23, Pneumovax 23, Merck) are indicated for a high-risk patient, these vaccines should not be given at the same visit. The PCV13 should be given first followed by PPSV23 at least 8 weeks later. If PPSV23 has already been given, wait 8 weeks (for a child) or 1 year (for an adult age 19 years or older) before giving PCV13 to avoid interference between the two vaccines.2) A person with anatomic or functional asplenia or HIV should receive both PCV13 and meningococcal ACWY (MenACWY) vaccines. If Menactra brand (Sanofi) MenACWY is used, the person should first receive all recommended doses of PCV13 followed by Menactra at least 4 weeks later. Menveo (GSK) or MenQuadfi (Sanofi) MenACWY brands can be given at the same time or at any time before or after PCV13.3) Cholera vaccine should be administered before TY21a vaccine, and 8 hours should separate cholera vaccine and the first dose of TY21a. A 5-year-old is in the office for vaccines and is due for MMR, polio, varicella, and DTaP. Is there a specific order I should be giving these vaccines? The Advisory Committee on Immunization Practices (ACIP) does not address this issue. There is no recommended order in which the vaccines should be given. A best practice strategy to decrease injection or procedural pain is to administer the vaccine that causes the most pain (stinging, for example) last. For more information on vaccine administration, please see the “Vaccine Administration” chapter of Epidemiology and Prevention of Vaccine-Preventable Diseases at, Do we need to wait for the vaccine to reach room temperature before we administer it to a patient? With the exception of two vaccines used to prevent smallpox or mpox (previously known as monkeypox), there is no recommendation to wait until a vaccine reaches room temperature before administration. The vaccine should be administered as soon as it is prepared. The live smallpox (vaccinia) vaccine, ACAM2000 (Emergent Product Development Gaithersburg, Inc.) and the non-replicating, live smallpox and mpox vaccine, Jynneos (Bavarian Nordic) should be brought to room temperature before use, according to the package inserts for these two products. What is the acceptable volume for a single dose of immune globulin (IG) to inject into the deltoid muscle of a normal-weight adult? What is the acceptable volume for a single dose of IG to inject into the vastus lateralis of a normal-weight adult? Here are the suggested volumes: Deltoid:

Average 0.5 mL
Range 0.5–2 mL

/td> Vastus Lateralis:

Average 1–4 mL
Range 1–5 mL

/td> Infants and toddlers would fall at the lower end of the range, whereas adolescents and adults would generally fall on the higher end of the range. If all needed vaccines aren’t administered during the same visit, does one need to wait a certain period of time before administering the other needed vaccines? All inactivated vaccines, including COVID-19 vaccines, can be given on the same day, or on any day before or after giving other inactivated or live vaccines. Early guidance from ACIP recommended against coadministration of COVID-19 vaccines with other vaccinations; however, ACIP updated its guidance in mid-2021 to state that these vaccines may be coadministered with other vaccinations when necessary. If two live vaccines are not given on the same day, they need to be spaced at least 4 weeks apart. If both pneumococcal conjugate vaccine (PCV) and 23-valent pneumococcal polysaccharide vaccine (PPSV23) are indicated for a high-risk patient, these vaccines should not be given at the same visit. The PCV should be given first followed by PPSV23 at least 8 weeks later. If PPSV23 has already been given, wait 8 weeks (for a child) or 1 year (for an adult age 19 years or older) before giving PCV to avoid interference between the 2 vaccines. A person with anatomic or functional asplenia should receive both PCV and meningococcal conjugate vaccines (MenACWY). If Menactra brand MenACWY is used the person should first receive all recommended doses of PCV then Menactra at least 4 weeks later. Menveo or MenQuadfi brands of MenACWY can be given at the same time or at any time before or after PCV. What does “simultaneous administration” of vaccines mean? Does it mean the same day, hour, or what? Simultaneous means the same day—the same clinic day. If someone receives a vaccine in the morning and then another that same afternoon, it would be considered simultaneous administration. Some manufacturers’ package inserts state that a vaccine should be used immediately after reconstitution. In the context of reconstitution and administration of vaccines, how does CDC define “immediately”? There are various requirements for the use of vaccines after reconstitution. Some manufacturers’ package inserts require that the vaccine be used or discarded in varying time frames ranging from 24 hours after reconstitution to immediately after reconstitution. While the specific timeframes are simple to interpret, there can be some confusion as to what the requirement of “immediately” actually means. CDC considers “immediately” to be the reasonable time it takes to prepare and transport the vaccine to the patient to be administered. This would include any limited documentation that may be related to this process. It is up to the judgment of a provider to determine if a vaccine has not been used in the appropriate time. Some manufacturers have indicated to providers that “immediately” can be up to 30 minutes. The definition of “immediately” varies from manufacturer to manufacturer. Some do not have the data to put forth a general time frame as to what “immediately” means. CDC recommends that the provider contact the manufacturer any time (s)he has any question about whether or not the vaccine has been used in the appropriate time frame. Does live oral cholera vaccine (Vaxchora, Emergent Travel Health) need to be administered at an interval from other live oral or injectable vaccines? In general, no. According to ACIP’s “General Best Practice Guidelines for Immunization”, concerns about spacing between doses of live vaccines not given at the same visit applies only to live injectable or intranasal vaccines. So live oral cholera vaccine may be administered simultaneously or at any interval before or after administration of most other vaccines. One exception is Ty21a oral typhoid vaccine (Vivotif, Emergent Travel Health) and oral cholera vaccine. Oral cholera vaccine should be administered before Ty21a vaccine, and at least 8 hours should separate the cholera vaccine and the first dose of Ty21a. We have a nurse in one of our clinics who gave separate doses of hepatitis A and hepatitis B vaccine in the gluteus. Are the doses of each antigen considered invalid? If so, can they be repeated at any time or do I need to count the spacing between doses from the date when the invalid dose was administered? Although the gluteus muscle is not a recommended site for vaccination, in general, a dose given there can be considered valid. The exceptions to this general rule are hepatitis B and rabies vaccines, so the hepatitis B vaccine should not be counted in this situation. The hepatitis B vaccine can be repeated immediately. See the Advisory Committee on Immunization Practice’s (ACIP) “General Best Practices Guidelines for Immunization”, available at, Is the “Z-track” method recommended for IM injections? ACIP does not address the use of this method for vaccination in its “General Best Practices Guidelines for Immunization” ( ). If you choose to use this method, you should still adhere to the ACIP’s recommendations regarding needle length and anatomical site. Is it safe to give a vaccine directly into an area where there is a tattoo? Both IM and SC vaccines may be given through a tattoo. Do you need to aspirate before giving a vaccination? No. ACIP does not recommend aspiration when administering vaccines because no data exist to justify the need for this practice. There are data that show that aspiration is more painful for the vaccine recipient. IM injections are not given in areas where large vessels are present. Given the size of the needle and the angle at which you inject the vaccine, it is difficult to cannulate a vessel without rupturing it and even more difficult to actually deliver the vaccine intravenously. We are aware of no reports of a vaccine being administered intravenously and causing harm in the absence of aspiration. While giving an injection, a nurse had blood return in the syringe upon aspirating. What should she have done with the vaccine? Although aspiration is not recommended, if you do aspirate and get a flash of blood, then the procedure is to withdraw the needle and start over. The syringe, needle, and contaminated dose of vaccine should be discarded in a sharps container, and a new syringe and needle should be used to draw up and administer another dose of vaccine. This is a waste of expensive vaccine that could be avoided by simply not aspirating. Is it necessary to wear gloves when we administer vaccinations? In general, no. Occupational Safety and Health Administration (OSHA) regulations do not require the wearing of gloves when administering vaccinations, unless the person administering the vaccine is likely to come into contact with potentially infectious body fluids or has an open lesion on their hand. If a healthcare worker chooses to wear gloves, he or she must change them between each patient encounter. In 2020, in response to the COVID-19 pandemic, CDC temporarily recommended the use of gloves when administering oral and intranasal vaccines to patients in communities where SARS-CoV-2, the virus that causes COVID-19, is circulating. Gloves were recommended to prevent contact with the recipient’s potentially infectious mucous membranes or respiratory secretions. In the setting of widely available and effective COVID-19 vaccines and treatments, CDC resumed recommending standard pre-pandemic infection control practices during vaccination. Is protective eyewear needed for those who administer vaccines so they can avoid blood spatter? ACIP does not specifically recommend eye protection when administering vaccines to prevent exposure to blood spatter. In 2020, in response to the COVID-19 pandemic, CDC temporarily recommended the use of protective eyewear in areas where SARS-CoV-2 was circulating widely to reduce the risk of infection with SARS-CoV-2. In the setting of widely available and effective COVID-19 vaccines and treatments, CDC resumed recommending standard pre-pandemic infection control practices during vaccination. Where can I find current information on how to protect myself and my patients when administering vaccines during the COVID-19 pandemic? In 2020, in response to the COVID-19 pandemic, CDC temporarily recommended additional infection control steps to ensure the safety of people in vaccination clinics, including universal wearing of face masks to reduce the risk of transmission. In the setting of widely available and effective COVID-19 vaccines and treatments, CDC resumed recommending standard pre-pandemic infection control practices during vaccination. The use of face masks to protect patients or staff from respiratory viruses while administering vaccinations should be based on professional judgment in the specific circumstances and/or institutional policy. Some single-dose manufacturer-filled vaccines come with an air pocket in the syringe chamber. Do we need to expel the air pocket before vaccinating? No. You do not need to expel the air pocket. The air will be absorbed. This is not true for syringes that you fill yourself; you should expel air bubbles from these syringes prior to vaccination to the extent that you can do so. I’ve seen the recommendation stating air bubbles in manufacturer-filled syringes do not need to be expelled. Can you explain why those air bubbles can be injected but air bubbles in user-filled syringes must be expelled? It is not wrong to expel the air from syringes filled by manufacturers, but typically it is such a small amount of air (0.2cc–0.3cc) that it is CDC’s opinion that it would not cause a problem. When the syringe is inverted during an injection, that small amount of air would typically just clear the medication from the needle. This is based on the recommendation that when the Z-track method is used for intramuscular injection of irritating medication (e.g., iron preparations), the guidance is to leave 0.2cc–0.3cc in the syringe to be sure that all of the medication leaves the needle and is not tracked back through subcutaneous tissue as the needle is withdrawn. While the Z-track injection technique is not recommended for vaccine administration, the Z-track method demonstrates the acceptability of leaving a very small amount of air in the syringe for intramuscular injections. CDC does, however, recommend that when drawing vaccine from a vial into a regular syringe, the air be expelled because the amount of air drawn into the syringe may be larger than the amount in a manufacturer-filled syringe. Expelling the air is part of general medication guidelines for drawing medication into a syringe. If a patient is not able to receive rotavirus vaccine orally, can we give it through a G-tube? You can give rotavirus vaccine through a tube as long as the child is otherwise eligible. If the lymph nodes under a patient’s arm were surgically removed, should we avoid giving vaccines in that arm? We are aware that some surgeons advise against vaccination in an arm where lymph nodes were dissected. ACIP does not address this, so feel free to use your professional judgment in determining whether to use the arm that was operated on, the other arm (if not affected), or the anterolateral aspect of the thigh, which is an acceptable secondary route for adult immunization. What are the special recommendations for administering intramuscular injections in people with clotting disorders? This issue is discussed in ACIP’s “General Best Practices Guidelines for Immunization” ( ). Intramuscular (IM) injections should be scheduled shortly after antihemophilia therapy or prior to a dose of anticoagulant. For both IM and subcutaneous (SC) injections, a fine needle (23 gauge or smaller) should be used and firm pressure applied to the site, without rubbing, for at least 2 minutes. Providers should not administer a vaccine by a route that is not approved by the FDA for that particular vaccine (e.g., administration of IM vaccines by the SC route). We have a question concerning delaying vaccinations for an infant born to a heroin-addicted mother. We had a foster parent come into our health department requesting only certain vaccines for a 3-month-old, stating that the private physician recommends delaying the schedule due to the possible residual effects of the heroin. The baby appeared to be healthy. Heroin use or addiction of the mother is not a reason to delay vaccination of an otherwise healthy infant. Is it okay to draw up vaccines at the beginning of the shift? If it isn’t, how much in advance can this be done? The ACIP discourages the practice of prefilling vaccine into syringes, primarily because of the increased possibility of administration and dosing errors. An exception may be considered when only a single type of vaccine is to be administered during a clinic (e.g., influenza). Another reason to discourage the practice in general is that some vaccines have a very limited shelf life after reconstitution. If the reconstituted vaccine is not used within the designated time period, it must be discarded. A chart of the time allowed between reconstitution and use, “Vaccines with Diluents: How to Use Them,” is available at, For more information on prefilling syringes, please read, If you place a needle on a manufacturer-filled syringe and then don’t administer the vaccine, how long can you store the syringe with the needle attached? In general, a vaccine should not be prepared until the provider is ready to administer it to a patient. This is because once the syringe cap is removed or a needle is attached, the sterile seal is broken. However, if a sterile seal has been broken, staff should be sure to maintain the syringe at the appropriate temperature and either use it or discard it at the end of the clinic day. This issue is addressed in the CDC Storage and Handling Toolkit, available at, page 20. My nurse removed the protective cap from a preservative-free single dose vial, but the vial was not used. How long can we keep a vial of vaccine after we remove the protective cap of a preservative-free vial of vaccine? Removing the protective cap increases the likelihood the septum or stopper could be punctured. The puncture may not be visible. It is important to ensure that the rubber seal on single-dose vials is not punctured because single-dose vials do not contain a preservative. Once the protective cap has been removed, the vaccine should be discarded at the end of the workday because it may not be possible to determine if the rubber seal has been punctured. For additional details, see CDC’s Vaccine Storage & Handling Toolkit at, Is it necessary to allow alcohol to dry completely on a patient’s skin prior to injection? It is prudent to allow the alcohol to evaporate, but it is unlikely that the small amount residual alcohol on the skin will affect the vaccine or increase the risk of an adverse reaction. Is it recommended to use a new alcohol swab to cleanse the skin before administering a vaccine, or can we swab the skin with the same alcohol swab that we used to wipe off the stopper on the vial? You should use separate alcohol wipes to clean the vial top and the patient’s skin. I know that it is advisable to clean the vaccine vial stopper with an alcohol wipe after removing the protective cap from a vaccine or diluent vial. Do you have to wait for the alcohol to dry before you insert the needle in to the stopper? The stopper of a single-dose vial is often assumed to be sterile. However, not all vaccine manufacturers guarantee the tops of unused vials are sterile, and the manner in which the cover over the stopper is removed can potentially contaminate the stopper. Therefore, using friction and a sterile alcohol pad to swab the stopper may help to assure aseptic technique in preparing the single-dose vial prior to inserting a sterile syringe. Alcohol evaporates quickly and will dry while the needle is being prepared for insertion into the vial. In cleaning the vaccine vial stopper or the patient’s skin, is it okay to use a non-sterile cotton ball or do we need to use a pre-packaged sterile alcohol prep pad? Using a pre-packaged sterile alcohol prep pad is recommended to maintain aseptic technique. Not only are cotton balls not sterile, but neither is a bottle of sterile alcohol, once it’s opened. Some single dose vials (SDV) contain more than the recommended dosage of the vaccine. Should we administer the recommended dose of the vaccine, or the entire contents of the vial even if it contains more than the recommended dose? In general the entire volume should be used even if it is a little more than 0.5 mL. Discarding the excess vaccine is not required or recommended. An exception to this is recombinant zoster vaccine (RZV; Shingrix, GSK). The RZV adjuvant solution may contain up to 0.75 mL of liquid. The entire volume of the adjuvant solution should be withdrawn and used to reconstitute the lyophilized vaccine. After mixing, withdraw the recommended dose of 0.5 mL. Any reconstituted vaccine left in the vial should be discarded. Where can I obtain standing orders for vaccination? has developed suggested standing orders for all vaccines commonly given to children and adults. They are based on CDC’s Advisory Committee on Immunization Practices (ACIP) recommendations. You can find the standing orders and protocols for medical management of vaccine reactions at, What is the provider’s liability when using standing order protocols? While you did not say this explicitly, we assume the concern is about a vaccine injury in a person who was vaccinated using a standing order. Of course, as long as the person is properly screened for contraindications and precautions, an injury from a vaccine is very unlikely. In the event that an injury does occur, the National Vaccine Injury Compensation Program (VICP) provides liability protection for the vaccinator and the clinician who signed the standing order for any vaccine that is covered by the vaccine injury compensation program (all vaccines that are routinely administered to children are covered by the program for all ages of patients). More information about the VICP is available on their website at, A 2009 article in The Lancet reported that infants who received 3 doses of paracetamol following immunization had reduced immune responses to certain vaccines. Based on these findings, should we stop recommending acetaminophen for fever or discomfort after infant immunizations? Findings of this study discourages the prophylactic use of paracetamol (similar to acetaminophen) prior to or immediately following vaccination. Acetaminophen can be used to treat pain or fever if it should occur following vaccination. ACIP’s “General Best Practices Guidelines for Immunization” state: “Evidence does not support use of antipyretics before or at the time of vaccination; however, they can be used for the treatment of fever and local discomfort that might occur following vaccination. Studies of children with previous febrile seizures have not demonstrated antipyretics to be effective in the prevention of febrile seizures.” For more information on this issue, see Methods for Alleviating Discomfort and Pain Associated with Vaccination at, What guidance is there for preventing patients from fainting after vaccination? All providers who administer vaccinations should be aware of the potential for syncope (fainting) after vaccination and take appropriate measures to prevent it. Thus, clinicians should (1) make sure that people who are being vaccinated are always seated; (2) be aware of symptoms that precede fainting (weakness, dizziness, pallor, etc.); and (3) take appropriate measures to prevent injuries if such symptoms occur. has two pertinent educational pieces for healthcare professionals: “Medical Management of Vaccine Reactions in Children and Teens in a Community Setting” at and “Medical Management of Vaccine Reactions in Adults in a Community Setting” at, CDC studies have shown that about 80% of fainting episodes occur within 15 minutes of receiving the vaccine. Vaccine providers should strongly consider observing vaccinated people for 15 minutes after vaccination in accordance with ACIP’s ” Are vaccine diluents interchangeable? Diluents are not interchangeable, except for the sterile water used in Merck’s measles-mumps-rubella (MMR), measles-mumps-rubella-varicella (MMRV), and varicella vaccines. No other diluent can be used for these vaccines, and these diluents must not be used to reconstitute any other lyophilized vaccine. If the wrong diluent is used, the vaccination should always be repeated. If an inactivated vaccine is reconstituted with the wrong diluent and is administered, the dose is invalid and should be repeated as soon as possible. If a live vaccine is reconstituted with the wrong diluent and is administered, the dose is invalid. If the dose can’t be repeated on the same clinic day, it needs to be repeated no earlier than four weeks after the invalid dose. This spacing is due to the effects of generating a partial immune response that could suppress the live replication of subsequent doses, even of the same live vaccine. has produced a printable document with details about vaccines that require diluents and how to use them:, Is it recommended to change needles after a vaccine dose has been drawn into a syringe? No. It is also unnecessary to change the needle if it has passed through two stoppers, which is done when a lyophilized vaccine is reconstituted. Changing needles is a waste of resources and increases the risk of needle stick injury. When patients need multiple vaccines (such as influenza and pneumococcal), can we just combine them in the same syringe? Absolutely not. No vaccines should ever be mixed in the same syringe unless the combination has been specifically approved by the FDA. The needle came loose while I was injecting a dose of vaccine, and approximately half the dose was lost. Should we revaccinate the patient? If so, when? When injectable vaccine volume is lost (patient moves, syringe leaks), it may be difficult to judge how much vaccine the patient actually received. Use your discretion to determine whether an adequate dose was given. In general, you should treat this as a nonstandard injectable dose and should not count it. If it was an inactivated vaccine, you should re-immunize the person as soon as possible. In the case of Shingrix (RZV; GSK) if the person is still in the office the dose can be repeated immediately; however, if the repeat Shingrix dose cannot be given on the same day CDC recommends that it should be given 4 weeks after the invalid dose. If it was a live vaccine, you can give another dose if you detect the error on the same clinic day; otherwise, you should wait 28 days to give the next dose. However, if part of a dose of an oral vaccine (rotavirus) was spit out by an infant, count the dose and do not administer a second dose. If a person sneezes after live attenuated influenza vaccine (Flumist; AstraZeneca) the dose can be counted as valid. If a patient pulls away during administration of a vaccine and the needle comes out, is it okay to reintroduce the same needle and finish the injection? No. The needle should be considered to be contaminated. The needle and syringe should be discarded. A new syringe, needle, and dose of vaccine should be used. Generally, a full repeat dose should be given, but you may use your clinical judgment to decide whether an adequate dose was administered before the patient pulled away. We run a student health center and are wondering what the position is on discarding empty vaccine vials. Do they need to go in a sharps container after they are drawn up or can they go in the trash? Empty or expired vaccine vials are considered medical waste and should be disposed of according to state regulations. We received a report of an infant who received rotavirus vaccine intramuscularly rather than orally. Is this dose valid? If not, when should it be repeated? The rotavirus vaccine dose given by the intramuscular route is not valid and should be repeated by the oral route as soon as possible. In a review of such rotavirus vaccine administration errors, there usually were not adverse reactions, and those documented were limited to local reactions and general, brief irritability. Please see, page 81, for more information. Please take steps to ensure that such vaccine administration errors are avoided in the future. This event should be reported to the Vaccine Adverse Event Reporting System at even if an adverse reaction does not result from it. What should we do if a dose of expired vaccine is given to a patient? The dose should be repeated. If the expired dose is a live virus vaccine, you should wait at least 4 weeks after the previous (expired) dose was given before repeating it. If the expired dose is not a live vaccine, the dose should be repeated as soon as possible. Although simply repeating the dose is preferred, serologic testing to check for immunity after certain vaccinations (e.g., measles, rubella, varicella, hepatitis A) may be accepted. MMRV was mistakenly given to a 31-year-old instead of MMR. Can this be considered a valid dose? Yes, however, this issue is not addressed in the 2010 MMRV ACIP recommendations. Although this is off-label use, CDC recommends that when a dose of MMRV is inadvertently given to a patient age 13 years and older, it may be counted towards completion of the MMR and varicella vaccine series and does not need to be repeated. An expired dose of ProQuad (MMRV, Merck) was given to a patient. We assume that the repeat dose should be given in three months because the spacing between doses of a combination vaccine depends on the longest minimum interval of a component (in this case the varicella vaccine component). Is this correct? In the case of an expired live vaccine, the issue is not necessarily the routine minimum interval (three months in the case of varicella and ProQuad vaccines), but the interval that would prevent viral interference if the expired vaccine happened to be still viable. This interval is considered to be four weeks (28 days). The repeat dose should be administered four weeks after the expired dose. What should we do if we give an injection by the wrong route (SC instead of IM)? Your practice should put procedures in place to ensure that you always give vaccines by the recommended route because data regarding safety and efficacy of alternate routes are limited. If this does inadvertently happen, ACIP and/or CDC recommends that if hepatitis B, rabies, HPV and inactivated influenza vaccines are administered subcutaneously the doses should not be counted as valid and should be repeated. ACIP states that If PCV13, Hib, and/or DTaP are administered by the subcutaneous route, providers have the discretion to repeat the doses. There is no minimum interval between the invalid dose and the repeat dose. ACIP and/or CDC recommends that if HepA, MenACWY, IPV, PPSV23, COVID-19, and RZV vaccines are administered subcutaneously, the doses can count and do not need to be repeated. ACIP/CDC has no recommendation for Tdap, Td, MenB, Typhim VI, or JE-VC. One of our staff gave a dose of pediatric hepatitis A vaccine to an adult patient by mistake. How do we remedy this error? In general, if the error is discovered on the same clinic day, you can administer the other “half” of the dose on that same day. If the error is discovered later, the dose should not be counted, and then the person should be recalled to the office and given a full age-appropriate repeat dose. There are, however, two exceptions to the general rule: (1) If a patient sneezes after receiving nasal-spray live attenuated influenza vaccine, count the dose as valid. (2) If an infant regurgitates, spits, or vomits during or after receiving oral rotavirus vaccine, count the dose as valid. If you give more than an age-appropriate dose, count the dose as valid and notify the patient/parent about the error. Using larger than recommended dosages can be hazardous because of excessive local or systemic concentrations of antigens or other vaccine constituents. Avoid such errors by checking the vaccine vial label 3 times. A dose of Kinrix (DTaP-IPV; GSK) should have been administered to a 4-year-old, but Pentacel (DTaP-IPV-Hib; Sanofi Pasteur) was administered instead. Does the dose of DTaP count? Yes. The DTaP in the Pentacel can be counted. Although Pentacel is licensed as a 4-dose series and this may represent a fifth dose of Pentacel (in which case it would be off-label use), the dose of DTaP counts as the fifth dose of DTaP. A dose of pneumococcal conjugate vaccine was administered into my patient’s dialysis port. Does this dose count? There are no data on the effectiveness of pneumococcal conjugate vaccine given by the intravenous route. The patient has renal disease, so it is important to ensure that the dose they receive is effective. CDC recommends repeating the dose. A 2-month-old was mistakenly given PPSV23. What should be done? PPSV23 is not effective in children younger than 24 months of age. PPSV23 given at this age should not be considered to be part of the pneumococcal vaccination series. Pneumococcal conjugate vaccine should be administered as soon as the error is discovered. Any time the wrong vaccine is given, the parent/patient should be notified. We inadvertently gave both pneumococcal conjugate (PCV) and pneumococcal polysaccharide (PPSV) vaccines at the same visit. We are looking for guidance. Although PCV and PPSV23 should not be administered at the same visit, CDC does not recommend repeating either vaccine dose should this occur. You should inform the patient of the error and let them know that they will not need to repeat either dose. A 60-year-old patient was inadvertently given varicella vaccine instead of zoster vaccine. Should the patient still be given the zoster vaccine? If so, how long an interval should occur between the 2 doses? CDC recommends that if a provider mistakenly administers varicella vaccine to a person for whom zoster vaccine is indicated, no specific safety concerns exist, but the dose should not be considered valid. Recombinant zoster vaccine (RZV; Shingrix, GSK) should be administered at least 8 weeks after receipt of the varicella vaccine. However, if RZV is administered less than 8 weeks after the varicella vaccine, it does not need to be repeated. A second dose of RZV should be given 2–6 months after the first dose of RZV. Avoid such errors by checking the vial label 3 times to make sure you’re administering the product you intended. If RZV (Shingrix) is erroneously given to a child for prevention of varicella, the dose is invalid, but is there a waiting period before a valid dose of varicella vaccine can be given? Is it OK to give a dose of varicella vaccine as soon as the error is discovered? There is no waiting period. The varicella vaccine dose can be given at any time after the RZV dose. While giving a dose of RZV (Shingrix) the syringe came loose from the needle and part of the dose was lost. Will the patient be protected with this partial dose or does it need to be repeated? A dose less than the full 0.5 mL dose is not valid and should be repeated. If the patient is still in the office the dose can be repeated immediately. If the repeat dose cannot be given on the same day CDC recommends that it should be given 4 weeks after the invalid dose. My medical assistant inadvertently administered a 0.5 mL dose of the RZV (Shingrix) diluent only. The dose did not contain any antigen. When can we administer a properly reconstituted dose? The CDC zoster subject matter experts recommend that in this situation you should wait 4 weeks before giving a repeat dose. Several doses (antigen and diluent) of RZV (Shingrix) were mistakenly stored in our office freezer. One of these doses was administered to a patient. Is this dose valid and if not, when can it be repeated? Any RZV, either antigen or diluent, that is exposed to freezing temperature should not be used. If a dose exposed to freezing temperature is given to a patient the dose should be considered invalid and should be repeated 4 weeks after the invalid dose. Back to top

What are the benefits of bivalent COVID booster?

Bivalent COVID-19 boosters effectively protect against new omicron subvariants – UNC Gillings School of Global Public Health April 12, 2023 New research led by the UNC Gillings School of Global Public Health shows that bivalent COVID-19 boosters are still providing effective protection from hospitalization and death, even against the most recent omicron subvariants.

  1. Published this week in the New England Journal of Medicine (NEJM), researchers found that the bivalent boosters were 67% effective in preventing hospitalization and death in those who had been previously vaccinated or boosted.
  2. Effectiveness waned to 48% after four weeks, 44% after 10 weeks and 38% after 20 weeks.

Though the Pfizer and Moderna bivalent vaccines were initially designed to target the BA.4 and BA.5 strains of omicron, they also reduced the risk of infection, hospitalization and death against the currently circulating BQ.1/BQ.1.1 and XBB/XBB.1.5 strains. Dr. Danyu Lin “The effectiveness reported in our article pertains to the benefit of one additional dose, i.e., first booster compared to primary vaccination only, second booster compared to first booster or third booster compared to second booster. The effectiveness of bivalent boosters compared to being unvaccinated would be much higher,” says lead author, Dennis Gillings Distinguished Professor of Biostatistics.

The research team for this study also included and Yu Gu, doctoral students in biostatistics; and, professor of biostatistics at the Gillings School; as well as Shadia Khan Sunny, PhD, MPH, MBBS, senior epidemiologist; and Zack Moore, MD, MPH, state epidemiologist at the North Carolina Department of Health and Human Services. Contact the UNC Gillings School of Global Public Health communications team at,

: Bivalent COVID-19 boosters effectively protect against new omicron subvariants – UNC Gillings School of Global Public Health

What is the difference between Pfizer and Pfizer bivalent?

Novavax – The Novavax vaccine (brand names: Nuvaxovid and Covovax) was the fourth COVID-19 vaccine to be administered in the U.S. This vaccine, which is a protein adjuvant, had a 90% efficacy in its clinical trial, performing almost as well as the mRNA vaccines in their early trials.

It is simpler to make than some of the other vaccines and can be stored in a refrigerator, making it easier to distribute. Status: The vaccine was authorized in the U.S. in July 2022 and a booster was announced a few months later in October. The CDC says people should consider getting the Novavax vaccine if they are unable or choose not to get an updated Pfizer-BioNTech or Moderna COVID-19 vaccine.

Who can get it: People 12 and older. Dosage: 2 doses, 3-8 weeks apart. If you had COVID-19 recently, you might consider delaying your second primary dose or your booster by 3 months from when you started to experience symptoms or (if you had no symptoms) the date of your positive test result.

Who can get the booster: The Novavax booster protects against the original SARS CoV-2 virus and may not protect against recent Omicron subvariants. Adults who have not received a booster shot previously may choose to get it six months after completing their primary vaccination if they are unable to receive the bivalent booster for a medical or any other reason.

Alternatively, adults are eligible for a Pfizer-BioNTech or Moderna bivalent booster at least two months after their primary Novavax vaccination, and teenagers ages 12 through 17 must get a Pfizer-BioNTech bivalent booster. Possible side effects : Injection site tenderness, fatigue, headache, muscle pain.

There were rare cases of myocarditis and pericarditis (six cases in 40,000 participants) in the clinical trial. How it works: Unlike the mRNA and vector vaccines, this is a protein adjuvant (an adjuvant is an ingredient used to strengthen the immune response). While other vaccines trick the body’s cells into creating parts of the virus that can trigger the immune system, the Novavax vaccine takes a different approach.

It contains the spike protein of the coronavirus itself, but formulated as a nanoparticle, which cannot cause disease. When the vaccine is injected, this stimulates the immune system to produce antibodies and T-cell immune responses. How well it works : 90% effective overall against lab-confirmed, symptomatic infection and 100% effective against moderate and severe disease in Phase 3 trial results published in The New England Journal of Medicine  in December 2021.

While the efficacy was similar among participants from several demographic groups (the study looked at subgroups based on demographic characteristics, coexisting conditions, and those at high risk for COVID), efficacy was lower—at about 67%—in Hispanic or Latino participants, as compared to participants who were not Hispanic or Latino.

Notably there were few infections among people in the study who were Hispanic or Latino overall (just 8 in the Novavax group and 11 in the placebo group), making these results somewhat difficult to interpret. How well it works on virus variants: The data presented to the FDA was gathered before Omicron or its recent subvariants started to circulate, but the company says it expects to have a vaccine that will protect against the recent Omicron subvariants in 2023.

Note: None of the COVID-19 vaccines change—or interact with—a recipient’s DNA. Information provided in Yale Medicine articles is for general informational purposes only. No content in the articles should ever be used as a substitute for medical advice from your doctor or other qualified clinician. Always seek the individual advice of your health care provider with any questions you have regarding a medical condition.

This article was reviewed by Yale Medicine infectious diseases specialist Jaimie Meyer, MD, MS,

Should i get the bivalent vaccine booster?

High-risk populations are strongly recommended to receive their bivalent booster as soon as they are eligible after the minimum three-month interval since their last dose or following symptom onset or a positive COVID-19 infection to stay protected from the most serious effects of COVID-19 during this respiratory

How effective is the COVID bivalent booster?

Summary – What is already known about this topic? Bivalent mRNA COVID-19 vaccines help provide protection against medically attended COVID-19–associated illness. However, the durability of this protection is uncertain. What is added by this report? Among adults aged ≥18 years without immunocompromising conditions, bivalent booster vaccine effectiveness (VE) against COVID-19–associated hospitalization declined from 62% at 7–59 days postvaccination to 24% at 120–179 days compared with VE among unvaccinated adults.

Among immunocompromised adults, lower bivalent booster VE was observed. However, bivalent booster VE was sustained against critical COVID-19–associated outcomes, including intensive care unit admission or death. What are the implications for public health practice? Adults should stay up to date with recommended COVID-19 vaccines.

Optional additional bivalent vaccine doses are available for older adults and persons with immunocompromising conditions.