Ask the Experts: All Questions

Ask the Experts is one of our most popular destinations for healthcare professionals. Our experts provide clear, easy-to-understand answers to commonly asked questions about vaccines and their use.

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Results (1317)

The next dose should be given at 12 months of age. The child will also need another dose at least 28 days later. For the child to be fully vaccinated, they need to have 2 doses of MMR vaccine given when the child is 12 months of age and older. A dose given earlier than 4 days before the first birthday does not count as part of the MMR vaccine two-dose series.

Last reviewed: June 19, 2023

Yes, but only if the 9-year-old meets all of the criteria below:

  • they turned 9 years old during the current season, and
  • they received one dose during the current season before turning 9, and
  • they have no or unknown history of receiving any previous dose of influenza vaccine before July 1 of the current year.
Last reviewed: September 10, 2023

Absolutely not. Vaccines should never be mixed except when specifically approved by FDA and packaged for that specific purpose.

Last reviewed: July 15, 2023

Yes. Shingrix can be administered in this situation. Optimally, vaccination should occur when the disease is well-controlled and not during an acute disease flare.

Last reviewed: March 9, 2022

Yes. Any person who ever received 2 doses of any combination of HPV vaccines can be considered fully vaccinated if dose #1 was given before the 15th birthday and the 2 doses were separated by at least 5 months.

Last reviewed: March 2, 2024

Hepatitis A vaccine (HepA) should be administered intramuscularly (IM), using the appropriate injection site and needle size as determined by the patient’s age and body mass. See Immunize.org’s clinical resource, “How to Administer Intramuscular and Subcutaneous Vaccine Injections” for details, www.immunize.org/catg.d/p2020.pdf.

Last reviewed: June 25, 2023

In rare circumstances, nirsevimab may be considered for infants in their first RSV season who were born to RSV-vaccinated mothers. These situations may include:

  • infants born to mothers who have health conditions that might prevent an adequate maternal immune response to vaccination (an immunocompromising condition caused by disease or immunosuppressive treatment)
  • infants whose mothers have conditions associated with reduced transplacental antibody transfer (such as a mother living with HIV infection)
  • infants who might have lost maternal antibodies, such as those who have undergone cardiopulmonary bypass or extracorporeal membrane oxygenation (ECMO)
  • infants with substantially increased risk for severe RSV disease (such as hemodynamically significant congenital heart disease or intensive care admission requiring oxygen at hospital discharge).

Infants and children age 8–19 months who are at increased risk for severe RSV disease and are entering their second RSV season are recommended to receive nirsevimab regardless of history of maternal vaccination.

Last reviewed: January 22, 2024

For people with immunosuppression, ACIP recommends 1 dose of PCV20 alone or one dose of PCV15 followed by a dose of PPSV23 one year later (can consider a minimum 8-week interval between PCV15 and PPSV23 for immunocompromised adults like this woman). Meningococcal serogroup B vaccine (MenB) is not specifically recommended for immunosuppressed people. However, a patient who is age 16 through 23 years and immunosuppressed may receive routine MenB vaccination of either a 2-dose series of Bexsero (GSK) 4 weeks apart, or a 3-dose series of Trumenba (Pfizer) at 0, 1 month, and 6 months apart.

Last reviewed: April 5, 2024

A CDC study showed a small increased risk for febrile seizures during the 24 hours after a child receives the inactivated influenza vaccine at the same time as the PCV13 vaccine or DTaP vaccine. However, the risk of febrile seizure with any combination of these vaccines is small and ACIP recommends giving these vaccines at the same visit if indicated. The risk for febrile seizures in children who received PCV15 or PCV20 concurrently with an influenza vaccine has not been studied.

See www.cdc.gov/vaccinesafety/concerns/febrile-seizures.html for more information about febrile seizures after vaccination.

Last reviewed: April 5, 2024

In 2015, CDC revised the recommendation for the timing of hepatitis B serologic testing for infants born to an HBsAg-positive woman. Postvaccination testing (HBsAg and hepatitis B surface antibody [anti-HBs]) is now recommended 1 to 2 months after completion of at least three doses of the HepB vaccine series, but not before 9 months of age. For a child vaccinated on schedule, testing should be done at age 9 to 12 months. Testing should not be performed before age 9 months because hepatitis B immune globulin (HBIG) might still be present at age 6 to 8 months, nor should testing be performed within 1 month of the most recent HepB dose because a transient false positive HBsAg might occur. Antibody to hepatitis B core (anti-HBc) testing of infants or children is not recommended because passively acquired maternal anti-HBc might be detected up to age 24 months in children of HBV-infected mothers. Children who are HBsAg positive should receive medical evaluation and ongoing follow-up. For additional information, see www.cdc.gov/mmwr/pdf/wk/mm6439.pdf, pages 1118–20.

Last reviewed: July 21, 2023

According to CDC’s interim clinical considerations for the use of COVID-19 vaccines, whenever possible, COVID-19 vaccines should be administered at least 2 weeks before initiation or resumption of immunosuppressive therapies. For patients who receive B-cell-depleting therapies on a continuing basis, COVID-19 vaccines should be administered approximately 4 weeks before the next scheduled therapy.

CDC also notes that timing of COVID-19 vaccination should take into consideration current or planned immunosuppressive therapies, optimization of both the patient’s medical condition and response to vaccination, and individual benefits and risks. Review the CDC’s considerations for COVID-19 vaccination of those on immunosuppressive therapies here: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#considerations-timing-COVID-19-vaccination-immunosuppressive-therapies.

Last reviewed: March 19, 2024

No vaccine series needs to be restarted because of an interval that is longer than recommended (with the exception of oral typhoid vaccine in certain circumstances). You should resume the HPV vaccine series where it was interrupted.

Last reviewed: March 2, 2024

In 2005, ACIP recommended routine MenACWY vaccination for all preteens at age 11 or 12 years to protect them from meningococcal disease when its incidence rises in the late teens and early 20s. Subsequent studies indicated that the protection provided by MenACWY wanes within 5 years following vaccination. For this reason, in 2010, ACIP recommended a MenACWY booster dose at age 16 to provide continuing protection during the age of increased meningococcal incidence.

Last reviewed: March 24, 2024

ACIP recommends the following for the use of Tdap in healthcare personnel:

  • All healthcare personnel (HCP), regardless of age, should receive a single dose of Tdap as soon as feasible if they have not previously received Tdap and regardless of the time since last Td dose.
  • Tdap may be administered in any situations where Td only was previously recommended. After receipt of Tdap, HCP should receive routine booster immunization against tetanus and diphtheria with either Td or Tdap vaccine. Additionally, pregnant HCP should receive a dose of Tdap during each pregnancy.
  • Hospitals and ambulatory-care facilities should provide Tdap for HCP and use approaches that maximize vaccination rates (e.g., education about the benefits of vaccination, convenient access, and the provision of Tdap at no charge).

To view updated recommendations on the use of Td or Tdap in situations where only Td was previously recommended, go to www.cdc.gov/mmwr/volumes/69/wr/pdfs/mm6903a5-H.pdf. For details about Tdap and other recommendations for healthcare personnel, go to “Immunization of Health-Care Personnel” (MMWR 2011;60[SS-7]:4-46) at www.cdc.gov/mmwr/pdf/rr/rr6007.pdf.

Last reviewed: March 31, 2022

No. IG may contain antibodies to measles, mumps, and rubella that could reduce the effectiveness of MMR vaccine. For this reason, in February 2018 ACIP voted to recommend that hepatitis A vaccine should be administered to infants age 6 through 11 months traveling outside the United States when protection against hepatitis A is recommended. MMR and hepatitis A vaccines may be safely co-administered to children in this age group. Neither vaccine is counted as part of the child’s routine vaccination series. For details of this recommendation, see the CDC ACIP recommendations for the prevention and control of hepatitis A at www.cdc.gov/mmwr/volumes/69/rr/pdfs/rr6905a1-H.pdf, page 18.

Last reviewed: June 19, 2023

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 www.hrsa.gov/vaccinecompensation/index.html.

Last reviewed: December 28, 2022

Twelve weeks. The spacing between doses of a combination vaccine depends on the longest minimum interval of a component. The minimum interval between doses of MMR is 4 weeks; the minimum interval between doses of varicella vaccine is 12 weeks for a child this age. So, you should wait 12 weeks between the doses of MMRV for the two doses to be valid.

Last reviewed: July 15, 2023

For patients receiving anti-B cell therapies (e.g., rituximab), CDC recommends administering a dose of RZV approximately 4 weeks prior to the next scheduled therapy.

Last reviewed: March 9, 2022

A booster dose should be given to first-year college students, regardless of age, who are or will be living in a residence hall if the previous dose was given before the age of 16 years or if their most recent dose (given after the 16th birthday) was not given within the past 5 years.

Last reviewed: March 24, 2024

Nirsevimab dosing is based upon weight and/or age. It is available in 50-mg or 100-mg manufacturer-filled syringes (MFS). Infants younger than 8 months and weighing less than 5 kgs (11 lbs.) should receive a 50-mg dose, given as a 50-mg MFS. Infants younger than 8 months and weighing 5 kg (11 lb.), or more, should receive a single 100-mg dose, given as a 100-mg MFS. Infants and toddlers age 8 months through 19 months who need nirsevimab should receive a 200-mg dose, given as two 100-mg MFS.

Do not administer two 50-mg MFS to an infant who needs a 100-mg MFS. The supply of 50-mg MFS is intended for the smallest infants. The cost of the 50-mg and 100-mg MFS are equivalent, despite the difference in dose; insurance plans may not cover the cost of two doses given to an infant not recommended to receive two doses. Only high-risk children age 8 through 19 months are recommended to receive two (100-mg) MFS doses at the same visit.

See the Immunize.org standing order template for details: www.immunize.org/wp-content/uploads/catg.d/p3097.pdf.

Last reviewed: January 22, 2024

Mesalamine (mesalazine) is a non-steroidal anti-inflammatory drug. It is not immunosuppressive, so its use would not place a person at increased risk of invasive pneumococcal disease.

Last reviewed: April 5, 2024

Yes. It is especially important to vaccinate during pregnancy because of the increased risk for influenza-related complications during pregnancy and the baby’s increased risk of influenza-related illness and hospitalizations during the first 6 months of life.

Influenza vaccination during pregnancy reduces mothers’ risk of influenza illness, preterm labor, and their infants’ risk of influenza and influenza-related hospitalization in the first 6 months of life.

Vaccination can occur in any trimester, including the first. Only inactivated or recombinant influenza vaccines may be given during pregnancy. FluMist, a live vaccine, should not be given during pregnancy.

Last reviewed: September 10, 2023

There is no minimum period to wait to correct your error. If you had immediately realized that you had mistakenly given the father-to-be Td instead of Tdap, you could have given him the needed Tdap dose at the same visit at which you gave him the erroneous Td dose.

Last reviewed: March 31, 2022

The IDSA guidelines indicate that persons receiving rituximab should be considered to have high-level immunosuppression. Both inactivated and live vaccines should be withheld at least 6 months following treatment with lymphocyte depleting medications such as rituximab. As for the IG, the interval to live vaccination depends on the dose. For guidance, please refer to the Timing and Spacing of Immunobiologics section of CDC’s “General Best Practices Guidelines for Immunization”, table 3–6: “Recommended intervals between administration of antibody-containing products and measles- or varicella-containing vaccine, by product and indication for vaccination” at www.cdc.gov/vaccines/hcp/acip-recs/general-recs/timing.html. This interval could be as long as 11 months, depending on the dose he receives.

Last reviewed: May 16, 2023

Yes. The second dose of MMR may be scheduled a minimum of 28 days after the first dose, if necessary.

Last reviewed: June 19, 2023

HPV vaccine is not recommended for use during pregnancy. HPV vaccines have not been associated causally with adverse outcomes of pregnancy or adverse events in the developing fetus. However, if a person is found to be pregnant after initiating the vaccination series, the remainder of the series should be delayed until completion of pregnancy. Pregnancy testing is not needed before vaccination.

If a vaccine dose has been administered during pregnancy, no intervention is needed.

Last reviewed: March 2, 2024

Yes. Other inactivated and/or live virus vaccines can be administered at the same time as HepA vaccine, but should be given at a different anatomical site, if possible. If given in the same muscle, separate the injections by a minimum distance of 1 inch.

Last reviewed: June 25, 2023

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 www.cdc.gov/vaccines/hcp/acip-recs/general-recs/administration.html.

Last reviewed: December 28, 2022

CDC states that no additional medical documentation is required before vaccination. People may simply affirm that they are moderately or severely immunocompromised and receive COVID-19 vaccine doses wherever vaccines are offered. Vaccinators should not deny COVID-19 vaccination to a person due to lack of documentation.

Last reviewed: March 19, 2024

HBsAg-negative infants with anti-HBs levels 10 mIU/mL or higher are protected and need no further medical management. HBsAg-negative infants with anti-HBs less than 10 mIU/mL should be revaccinated with a single dose of hepatitis B vaccine and receive postvaccination serologic testing 1–2 months later. Infants whose anti-HBs remains less than 10 mIU/mL following single dose revaccination should receive 2 additional doses of HepB to complete the second series, followed by postvaccination serologic testing 1–2 months after the final dose.

Based on clinical circumstances or family preference, HBsAg-negative infants with anti-HBs less than 10 mIU/mL may instead be revaccinated with a second, complete 3-dose series, followed by postvaccination serologic testing performed 1–2 months after the final dose of vaccine.

Last reviewed: July 21, 2023

Shingrix has not been evaluated for, and is not recommended for, the prevention of primary infection with varicella virus (chickenpox).

In this case, the patient is not yet immunocompromised and has no evidence of immunity to varicella. The simplest next step is to vaccinate the patient with two doses of varicella vaccine, spaced at least 4 weeks apart, before initiating immunosuppressing medication.

If you wish, you may order a commercial serologic assay to look for evidence of past varicella virus exposure. However, remember that the sensitivity and specificity of these tests vary, and while such commercial tests can detect evidence of past varicella infection, they are not sensitive enough to reliably detect evidence of past vaccination with varicella vaccine.

For patients who lack evidence of past infection or vaccination and who are immunocompromised already, CDC has provided additional detailed clinical considerations here: www.cdc.gov/shingles/vaccination/immunocompromised-adults.html#special-populations.

Last reviewed: March 9, 2022

Yes. Doses of any quadrivalent meningococcal vaccine (MenACWY) given before 10 years of age should not be counted as part of the series. If a child received a dose of either MPSV4 (Menomune, a meningococcal polysaccharide vaccine not available in the United States since 2017) or MenACWY before age 10 years, they should receive a dose of MenACWY at 11 or 12 years and a booster dose at age 16 years. A dose of MenACWY administered at age 10 may count as the first adolescent dose normally given at 11 or 12.

Last reviewed: March 24, 2024

The supply of 50-mg manufacturer-filled syringes (MFS) should be reserved for infants weighing less than 5 kilograms (less than 11 pounds). In addition, insurers may not cover the cost of two 50-mg MFS doses administered to one infant. The cost of a single MFS is the same, whether it is a 50-mg MFS or a 100-mg MFS. Only high-risk children age 8 through 19 months are recommended to receive two (100-mg) MFS doses at the same visit.

Last reviewed: January 22, 2024

Multiple sclerosis is not a contraindication to any vaccine, including pneumococcal vaccines.

People with multiple sclerosis may be on immunosuppressive medication and immunosuppressed people should receive either PCV20 alone or PCV15 followed by PPSV23 a minimum of 8 weeks later.

For additional details, see www.cdc.gov/vaccines/vpd/pneumo/hcp/who-when-to-vaccinate.html#adults-19-64.

Last reviewed: April 5, 2024

ACIP has recommended vaccinating during pregnancy with inactivated influenza vaccine since 1997. Studies have shown that pregnant people are at increased risk for complications, hospitalization, and even death from influenza because of the increased physiologic strain of pregnancy on their heart, lungs, and immune system. Vaccination can occur in any trimester, including the first.

Infants younger than 6 months old are at high risk of influenza-related complications, but influenza vaccine is not recommended for them because the immune response to influenza vaccination is limited before 6 months of age. Vaccinating during pregnancy provides maternal antibodies to the fetus which  helps protect infants against influenza during the first 6 months of life until they can get vaccinated at age 6 months. Vaccinating pregnant people protects them, their unborn babies, and their babies after birth.

Last reviewed: September 10, 2023

Immunocompromised people who require an initial series of 3 doses of mRNA COVID-19 vaccine or two doses of Novavax COVID-19 vaccine should receive the initial series using the same brand, unless it is not feasible. If the same brand (referred to as a homologous dose) cannot be used for all primary series doses (e.g., the brand is unavailable at the time of the vaccination visit, the previous brand is unknown, or the patient would not be vaccinated with the previous brand due to a contraindication or other reason), then administer another appropriate brand. CDC recommends homologous doses for all doses administered to children younger than age 5 years. If the immunocompromised recipient is age 5 years or older, once the initial series is complete, any appropriate brand may be used for subsequent doses. CDC provides additional information at: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#Interchangeability.

Last reviewed: March 19, 2024

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.

Immunize.org has two pertinent educational pieces for healthcare professionals: “Medical Management of Vaccine Reactions in Children and Teens” at www.immunize.org/catg.d/p3082a.pdf and “Medical Management of Vaccine Reactions in Adult Patients” at www.immunize.org/catg.d/p3082.pdf.

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 General Best Practices Guidance for Immunization (see www.cdc.gov/vaccines/hcp/acip-recs/general-recs/administration.html). This is particularly important when vaccinating adolescents and young adults. CDC has posted additional information on this topic at www.cdc.gov/vaccinesafety/concerns/fainting.html.

Last reviewed: December 28, 2022

The ACIP’s varicella vaccine recommendations state that no adverse events associated with the use of salicylates after varicella vaccination have been reported, however, the vaccine manufacturer recommends that vaccine recipients avoid using salicylates for 6 weeks after receiving varicella vaccines because of the association between aspirin use and Reye syndrome after varicella disease (chickenpox). Vaccination with subsequent close monitoring should be considered for children who have rheumatoid arthritis or other conditions requiring therapeutic aspirin. The risk for serious complications associated with aspirin is likely to be greater in children in whom natural varicella develops than it is in children who receive the vaccine containing attenuated varicella zoster virus. In other words, the benefit of varicella vaccine likely outweighs the theoretical risk of Reye syndrome. See the ACIP varicella recommendations at www.cdc.gov/mmwr/PDF/rr/rr5604.pdf, page 29.

Last reviewed: May 16, 2023

You should withhold further HPV vaccine until she is no longer pregnant. After the pregnancy is completed, administer the remaining doses of the series using the usual 2- or 3-dose schedule (depending on the age at initiation of the series).

Last reviewed: March 2, 2024

Yes. ACIP recommends a dose of Tdap be given to all adults, including those age 65 years or older.

Last reviewed: March 31, 2022

Yes, VFC-supported HepA vaccine is available for children 12 months through 18 years who are VFC-eligible. In addition, combination HepA and HepB vaccine (Twinrix; GSK) is also available for people who are age 18 years who are VFC-eligible.

Last reviewed: June 25, 2023

No. A measles-containing vaccine administered more than 4 days before the first birthday should not be counted as part of the series. MMR should be repeated when the child is age 12 through 15 months (12 months if the child remains in an area where disease risk is high). The second dose should be administered at least 28 days after the first dose.

Last reviewed: June 19, 2023

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.

Last reviewed: July 15, 2023

Available data do not suggest a benefit from administering additional HepB vaccine doses to infants who have not attained anti-HBs of mIU/mL or higher following receipt of two complete HepB series. HBsAg-positive infants should be referred for appropriate follow-up with a physician who specializes in evaluating infants with liver disease.

Last reviewed: July 21, 2023

No. Antiretroviral treatment for HIV may improve immune response to vaccination; however, vaccination for shingles does not have to be delayed in order to achieve viral suppression, especially if this will significantly delay vaccine administration. Patients with advanced HIV should receive RZV, because the risk of shingles is further increased in the setting of such immune compromise.

Last reviewed: March 9, 2022

Studies done in children showed possible interference with the response to PCV7 when PCV7 and the Menactra brand of MenACWY-D (by Sanofi) were given simultaneously. For this reason, Menactra was recommended not to be given at the same time as PCV. However, Menactra is no longer available, so this is no longer a consideration.

Available brands of MenACWY, including MenACWY-CRM (Menveo, GSK), MenACWY-TT (MenQuadfi, Sanofi), as well as the pentavalent MenABCWY (Penbraya, Pfizer), may be administered at the same time or any time before or after any pneumococcal vaccine.

Last reviewed: April 5, 2024

Yes, nirsevimab may be coadministered with all other recommended age-appropriate vaccines. Nirsevimab should not interfere with the immune response to routine childhood vaccines when given together or at any time before or after them. Likewise, vaccination does not interfere with the effectiveness of nirsevimab.

When giving several injections at a single visit, separate intramuscular vaccines by at least 1 inch in the body of the muscle, if possible, to reduce the likelihood of overlapping local injection site reactions.

Last reviewed: January 22, 2024

Primary vaccination with the Janssen COVID-19 Vaccine requires only a single dose. People who received the Janssen COVID-19 Vaccine primary dose require only one updated (2023–2024 Formula) dose by Moderna, Pfizer-BioNTech, or Novavax to be up to date. People who are moderately or severely immunocompromised have the option to receive 1 additional updated 2023–2024 Formula COVID-19 vaccine dose at least 2 months later. Further additional dose(s) may be administered, informed by the clinical judgment of a healthcare provider and personal preference and circumstances. Any further additional doses should be administered at least 2 months after the last 2023–2024 Formula COVID-19 vaccine dose.

To evaluate an immunocompromised individual’s COVID-19 vaccine needs based upon the person’s age and COVID-19 vaccination history, use this infographic from CDC: www.cdc.gov/vaccines/covid-19/downloads/COVID19-vaccination-recommendations-immunocompromised.pdf.

Last reviewed: March 19, 2024

ACIP recommends routine booster doses of MenACWY for people two months old or older at ongoing high risk for meningococcal infection (see www.cdc.gov/mmwr/volumes/69/rr/pdfs/rr6909a1-H.pdf, Table 3). This group includes people (1) with persistent complement component deficiency (an immune system disorder) or who take a complement inhibitor (examples include eculizumab [Soliris] or ravulizumab [Ultomiris]), (2) with anatomic or functional asplenia, (3) with HIV infection, (4) who have higher risk of exposure (including microbiologists who handle Neisseria meningitidis isolates and travelers to or residents of areas with epidemic or hyperendemic meningococcal disease [such as the meningitis belt of sub-Saharan Africa]).

Children at continued high risk who received the last dose of the primary series of MenACWY before age 7 years should receive the next dose 3 years after the most recent dose, then every 5 years as long as risk remains. People at continued high risk who received the last dose of the primary series at age 7 years or older should receive the next dose 5 years after the most recent dose then every 5 years as long as risk remains. Menveo (MenACWY-CRM) is licensed through age 55 years; however, if MenQuadfi (MenACWY-TT, licensed for use at age 2 years and older) is unavailable for an adult age 56 years or older, you may use Menveo.

Last reviewed: March 24, 2024

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.

Immunize.org has produced a printable document with details about vaccines that require diluents and how to use them: www.immunize.org/catg.d/p3040.pdf.

Last reviewed: December 28, 2022

This is not necessary unless the person who was vaccinated develops a rash.

Last reviewed: May 16, 2023

ACIP recommends the following:

  • All adults age 19 years and older who have not yet received a dose of Tdap should receive a dose.
  • All pregnant people should receive a dose of Tdap during each pregnancy, preferably between 27 and 36 weeks’ gestation. Mothers who have never received Tdap and who do not receive it during pregnancy should receive it immediately postpartum.
  • A person who has not yet received a dose of Tdap can be given a dose of Tdap regardless of the interval since the person last received a tetanus or diphtheria toxoid-containing vaccine.
  • Providers should not miss an opportunity to vaccinate adults age 65 years and older with Tdap. When feasible, give Boostrix to adults age 65 and older. However, either vaccine product (Adacel or Boostrix) provides protection and is considered valid for use in people in this age group.
  • For adults not previously vaccinated with Tdap who need wound management care to prevent tetanus, Tdap is preferred over Td.
  • For adults who have received an initial dose of Tdap, Tdap may be administered in any situations where Td only was previously recommended, including as the decennial (every 10-years) booster dose.
Last reviewed: March 31, 2022

You do not need to start the series over again. The immunogenicity of 1 dose of HepA vaccine is 94% to 100%; studies have shown persistent protection from a single dose lasting more than 10 years. To ensure optimal long-term protection it is important to administer the second dose.

Last reviewed: June 25, 2023

Yes. A TST can be applied before or on the same day that MMR vaccine is given. However, if MMR vaccine is given on the previous day or earlier, the TST should be delayed for at least 28 days. Live measles vaccine given prior to the application of a TST can reduce the reactivity of the skin test because of mild suppression of the immune system.

Last reviewed: June 19, 2023

Pregnant people may receive any inactivated or recombinant influenza vaccine. They should not be given FluMist Quadrivalent because it is a live-virus vaccine.

Last reviewed: September 10, 2023

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.

Last reviewed: July 15, 2023

Yes. An HBsAg-positive mother who wishes to breastfeed should be encouraged to do so, including immediately following delivery. However, the infant should receive HBIG and HepB vaccine within 12 hours of birth. Although HBsAg can be detected in breast milk, studies done before HepB was available showed that breastfed infants born to HBsAg-positive mothers did not demonstrate an increased rate of perinatal or early childhood HBV infection. More recent studies have shown that, among infants receiving post-exposure prophylaxis to prevent perinatal HBV infection, there is no increased risk of infection among breastfed infants.

Last reviewed: July 21, 2023

Yes, administration of a different inactivated or live vaccine, either at the same visit or at any time before or after HPV vaccine, is acceptable because HPV is not a live vaccine.

Last reviewed: March 2, 2024

In pre-licensure clinical trials of Shingrix in immunocompetent adults age 50 years or older, the most common adverse reactions were pain at the injection site (78%), myalgia (45%), and fatigue (45%). Any grade 3 adverse event (reactions related to vaccination which were severe enough to prevent normal activities) was reported in 17% of vaccine recipients compared with 3% of placebo recipients. Grade 3 injection-site reactions (pain, redness, and swelling) were reported by 9% of vaccine recipients, compared with 0.3% of placebo recipients. Grade 3 solicited systemic events (myalgia, fatigue, headache, shivering, fever, and gastrointestinal symptoms) were reported by 11% of vaccine recipients and 2.4% of placebo recipients. The occurrence of local grade 3 reactions did not differ by vaccine dose. However systemic grade 3 reactions were reported more frequently after dose 2.

Rates of serious adverse events (an undesirable experience associated with the vaccine that results in death, hospitalization, disability or requires medical or surgical intervention to prevent a serious outcome) were similar in vaccine and placebo groups.

Among immunocompromised recipients of RZV, local grade 3 reactions occurred in 10.7% to 14.2% of RZV recipients, and systemic grade 3 reactions occurred in 9.9% to 22.3% of RZV recipients, compared with 0% to 0.3% and 6.0% to 15.5%, respectively, among placebo recipients. Limited studies have found no evidence of an increased risk of immune-mediated diseases, graft-versus-host-disease, or transplant rejection among certain categories of immunocompromised RZV recipients.

Last reviewed: March 9, 2022

Yes, people should receive additional booster doses (every 5 years) if they continue to be at increased risk for meningococcal ACWY infection.

Last reviewed: March 24, 2024

No, these two antibody preparations should not interfere with each other. Administer nirsevimab as recommended.

Last reviewed: January 22, 2024

In the absence of immunosuppressive treatment, a recent history of prostate cancer surgery alone is not an indication for pneumococcal vaccination among people younger than 65 years.

Last reviewed: April 5, 2024

The patient should receive an updated 2023–2024 COVID-19 mRNA dose now, if feasible, of the same brand as the initial two doses, in order to complete the 3-dose primary mRNA vaccine series recommended for people with moderate or severe immunocompromise. Advise the patient that he has the option to receive additional 2023–2024 Formula COVID-19 doses of any brand (at least 2 months apart) as needed, based on his clinical circumstances.

To evaluate an immunocompromised individual’s COVID-19 vaccine needs based upon the person’s age and COVID-19 vaccination history, use this infographic from CDC: www.cdc.gov/vaccines/covid-19/downloads/COVID19-vaccination-recommendations-immunocompromised.pdf.

Last reviewed: March 19, 2024

Before vaccination, providers should counsel Shingrix recipients about common expected systemic and local adverse reactions (see related question). Reactions to the first dose do not strongly predict reactions to the second dose.

If a patient experiences side effects, any local (e.g., redness, pain, swelling at the injection site) or systemic (e.g., fever, chills, headache, body aches) reactions typically go away within 72 hours after vaccination. It is generally not recommended to take medication for pain or fever (e.g., acetaminophen or ibuprofen) before vaccination; however, such medications may be taken to alleviate local or systemic symptoms after vaccination, if needed. Shingrix recipients should be encouraged to complete the series even if they experienced a grade 3 reaction to the first dose.

Last reviewed: March 9, 2022

Yes. No data exist on the efficacy or safety of HPV vaccine given by the Subcut route. All data on efficacy and duration of protection are based on a vaccine series administered by the IM route. In the absence of data on Subcut administration, CDC and the manufacturer recommend that a dose of HPV vaccine given by any route other than IM should be repeated. There is no minimum interval between the invalid (Subcut) dose and the repeat IM dose.

Last reviewed: March 2, 2024

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