Ask the Experts: All Questions

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Results (1317)

Use of DTaP-IPV solution as the diluent for the Hib component is specifically written both on the Pentacel box AND on the DTaP-IPV vial label. The DTaP-IPV component will count as valid doses of DTaP and IPV vaccines, but take measures to prevent this error in the future. You cannot mix the Hib component with sterile water. ActHib must ONLY be reconstituted with either the DTaP-IPV solution supplied with Pentacel, or with a specific ActHib saline diluent. If you have a vial of lyophilized ActHib but neither diluent, you must contact the manufacturer (Sanofi) and obtain ActHib diluent.

Last reviewed: July 15, 2023

Immunity is not considered lifetime, however, CDC does not currently have any recommendation related to revaccination with oral cholera vaccine. The duration of immunity beyond the 3-month period of clinical trial evaluation in people age 18 through 45 years following one dose is unknown. As more information becomes available, CDC will update its recommendations accordingly.

Last reviewed: June 6, 2023

Due to the variety of causes and consequences of altered immunocompetence, and limited studies of vaccination with these conditions, vaccination recommendations for primary and secondary immunodeficiencies are generally based upon expert opinion.

CDC’s “General Best Practice Guidelines for Immunization” outline vaccine recommendations for people with various types of altered immunocompetence here: www.cdc.gov/vaccines/hcp/acip-recs/general-recs/immunocompetence.html. For a summary of specific vaccine recommendations for people with different types of primary and secondary immunodeficiencies, refer to Table 8-1 at that site. Additional information is available in the 2013 Infectious Diseases Society of America (IDSA) expert guideline on vaccination of the immunocompromised host, which informed CDC’s recommendations: www.idsociety.org/practice-guideline/vaccination-of-the-immunocompromised-host/.

Last reviewed: August 22, 2020

Yes. Any occurrence of medical significance warrants a VAERS report. VAERS looks for trends, so such information is helpful. You can obtain more information about VAERS at vaers.hhs.gov or by calling (800) 822-7967.

Last reviewed: August 31, 2022

The rabies vaccine is not recommended for routine use in the general population. Anyone for whom the pre-exposure vaccine is recommended should not receive a dose when they are moderately or severely ill.

Last reviewed: May 14, 2023

No. The 3-dose series (at 0, 1–2 and 6 months) is intended to rapidly induce immunity to serogroup B meningococcal bacteria. If a microbiologist or other person at increased risk has received 2 doses of Trumenba separated by 6 months their vaccine series can be considered to be complete.

Last reviewed: March 24, 2024

There are no severe reactions known to occur following IPV.

Last reviewed: July 23, 2023

No. There are no acceptable serologic titers that can be used as evidence of protection against meningococcal A, C, W, and Y disease. In addition, the immunologic studies used for licensing purposes (serum bactericidal assay, SBA) are likely different from the serologic titers obtained at a doctor’s office (IgG antibody, for example). It is not clear what sort of testing is shown in the results you sent. However, even if SBA results are available, they cannot be used to assess whether there is a level of protection at the individual level.

Last reviewed: March 24, 2024

CDC recommends that you use only a temperature monitoring device (TMD) with a Certificate of Calibration Testing (also known as a Report of Calibration). This certificate provides the TMD’s level of accuracy compared to a recognized standard. This certificate comes with the TMD when it is purchased, and it is different than the manufacturer’s warranty. While all TMDs are calibrated during manufacturing, certified calibrated TMDs undergo a second individual calibration against a reference standard from an accredited testing laboratory. Calibration testing should be done every 2 to 3 years or according to the manufacturer’s suggested timeline to ensure the accuracy of the device continues to conform to nationally accepted standards. Additional information on this topic is available on page 11 of CDC’s Vaccine Storage and Handling Toolkit, available at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf.

Last reviewed: July 26, 2023

The following conditions and factors place some older adults at the highest risk for severe RSV infection:

  • chronic medical conditions such as lung diseases (including chronic obstructive pulmonary disease and asthma)
  • cardiovascular diseases (such as congestive heart failure and coronary artery disease)
  • moderate or severe immune compromise (either due to an immunocompromising disease or treatment with an immunosuppressing treatment)
  • diabetes mellitus
  • neurologic or neuromuscular conditions
  • kidney disorders
  • liver disorders
  • hematologic disorders

Other factors associated with increased risk include:

  • overall frailty
  • advanced age
  • residence in a nursing home or other long-term care facility
  • other underlying factors that a health care provider determines might increase the risk for severe respiratory disease
Last reviewed: January 22, 2024

NCVIA requirements apply to diphtheria, tetanus, pertussis, measles, mumps, rubella, polio, hepatitis A, hepatitis B, Haemophilus influenzae type b (Hib), varicella, seasonal influenza (inactivated and live attenuated), pneumococcal conjugate, meningococcal, rotavirus, and human papillomavirus (HPV) vaccine.

Last reviewed: June 6, 2023

In 2000, the first pneumococcal conjugate vaccine (PCV) was licensed in the U.S. This vaccine contained seven serotypes (4, 6B, 9V, 14, 18C, 19F, and 23F) of Streptococcus pneumoniae and became known as PCV7 (Prevnar by Wyeth, now Pfizer). Ten years later in February 2010, a new 13-valent product was licensed — PCV13 (Prevnar 13, Pfizer) — which added 6 new serotypes (1, 3, 5, 6A, 7F, and 19A). Together, these 13 serotypes accounted for the majority of invasive pneumococcal disease (IPD) in the U.S. at the time, including serotype 19A, which is the most common IPD-causing serotype in young children. In February 2010 ACIP recommended that healthcare providers transition from use of PCV7 to use of PCV13 for routine vaccination of children.

PCV7 was initially recommended for routine use in infants and children ages 2 through 59 months. The recommendations were expanded with the licensure of PCV13 to include vaccination of children age 60 through 71 months with underlying medical conditions, and also vaccination of older children, ages 6 through 18 years, with medical conditions placing them at increased risk of invasive pneumococcal disease.

PCVs were further updated with licensure for use in children of PCV15 in 2022 and PCV20 in 2023.

Last reviewed: April 5, 2024

There are two circumstances when a third dose of MMR is recommended. ACIP recommends that women of childbearing age who have received 2 doses of rubella-containing vaccine and have rubella serum IgG levels that are not clearly positive should receive 1 additional dose of MMR vaccine (maximum of 3 doses). Further testing for serologic evidence of rubella immunity is not recommended. MMR should not be administered to a pregnant woman.

In 2018, ACIP published guidance for MMR vaccination of people at increased risk for acquiring mumps during an outbreak. People previously vaccinated with 2 doses of a mumps virus–containing vaccine who are identified by public health authorities as being part of a group or population at increased risk for acquiring mumps because of an outbreak should receive a third dose of a mumps virus–containing vaccine (MMR or MMRV) to improve protection against mumps disease and related complications. More information about this recommendation is available at www.cdc.gov/mmwr/volumes/67/wr/pdfs/mm6701a7-H.pdf.

Last reviewed: June 19, 2023

The routinely recommended minimum age for Shingrix among immunocompetent adults is 50 years. However, if a dose is inadvertently administered to an immunocompetent adult 18 through 49 years of age CDC does not recommend repeating the dose. The second Shingrix dose should not be administered until the 50th birthday. This guidance does not appear in the most recent zoster ACIP statement but is in the General Best Practices Guidance (Table 3-1 in the Timing and Spacing of Immunobiologics section at www.cdc.gov/vaccines/hcp/acip-recs/general-recs/timing.html) and is based on guidance from CDC’s zoster subject matter experts.

Among people who are or will be immunosuppressed or immunodeficient due to disease or therapy, the minimum age for vaccination is 19 years.

Last reviewed: March 9, 2022

ACIP does not recommend routine Hib vaccination of healthy children 60 months of age or older, even if they have no prior history of Hib vaccination.

Last reviewed: February 5, 2024

Because HPV acquisition generally occurs soon after first sexual activity, vaccine effectiveness will be lower in older age groups as a result of prior infections. In general, exposure to HPV also decreases among individuals in older age groups. Evidence suggests that although HPV vaccination is safe for adults 27 through 45 years, population benefit would be minimal; nevertheless, some adults who are unvaccinated or incompletely vaccinated might be at risk for new HPV infection and might benefit from vaccination in this age range.

Last reviewed: March 2, 2024

Infants for whom the first dose of rotavirus vaccine was inadvertently administered at age 15 weeks or older should receive the remaining doses of the series at the routinely recommended intervals. Timing of the first dose should not affect the safety and efficacy of the remaining doses. Rotavirus vaccine should not be given after age 8 months 0 days even if the series is incomplete.

Last reviewed: June 7, 2023

Dengvaxia is a live-attenuated vaccine. Live virus vaccines are generally not recommended during pregnancy; however, people infected with DENV during pregnancy are at increased risk of severe dengue. Perinatal transmission may occur with peripartum maternal infection increasing the risk of symptomatic illness in the newborn. The ACIP recommendations classify pregnancy as a precaution to vaccination with Dengvaxia.

Pregnant people were not explicitly enrolled and studied in the Dengvaxia vaccine trials. A minimal number of pregnant women in the trial inadvertently received Dengvaxia. There was no increased frequency of adverse pregnancy outcomes (e.g., spontaneous abortion, intrauterine death, stillbirth) noted compared to the control group. However, due to the small sample size, no conclusions can be made on the possible effect of Dengvaxia on pregnancy.

Providers should consider the pregnant person’s risk of DENV infection and its complications when deciding whether or not to recommend Dengvaxia during pregnancy or to defer until after pregnancy.

Last reviewed: February 16, 2022

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.

Last reviewed: December 28, 2022

If the first dose of a tetanus toxoid-containing vaccine is administered before the first birthday, 4 doses are necessary before beginning the 10-year cycle of booster doses. If the first dose is administered after the first birthday, 3 doses are necessary. The final dose should be spaced 6 months from the previous dose.

Last reviewed: March 31, 2022

Most likely this person has a resolved HBV infection and is immune. However, it would be preferable to test her again for all these serologic markers, and also quantify the anti-HBs result. If the results are still positive for anti-HBc, and anti-HBs is less than the immune level of 10 mIU/mL, you can give her one dose of HepB vaccine and test again in 1–2 months. If the anti-HBs is positive (10 mIU/mL or higher), she is immune. No further action is needed other than to document the results. If the anti-HBs is still negative, complete the vaccine series and test again 1–2 months after the last dose of vaccine.

Last reviewed: July 21, 2023

In the ten years following vaccine licensure in 1995, there was a significant decline in varicella disease, as well as varicella-related hospitalizations and deaths. Although a 1-dose regimen was estimated to be 80% to 85% effective, breakthrough disease was still occurring in highly vaccinated populations. A 2-dose regimen was adopted in 2006 to further reduce the risk of disease among vaccinated people whose numbers would accumulate over time, which could lead to varicella disease later in life when it can be more severe.

Last reviewed: May 16, 2023

Children age 6 months through 8 years should receive a second dose 4 weeks or more after the first dose 1) if they are receiving influenza vaccine for the first time, 2) if they have not received a total of at least two doses of any seasonal influenza vaccine before July 1 of the current year, or 3) if their vaccination history is unknown. The two previous doses need not have been received during the same season or consecutive seasons.

Children who are 8 years old and are recommended to receive two doses during the current season but who have a 9th birthday during the current season before receiving dose 2 should still receive dose 2.

Immunize.org’s handout titled “Guide for Determining the Number of Doses of Influenza Vaccine to Give to Children Age 6 Months Through 8 Years” provides additional guidance on this issue; it is available at www.immunize.org/catg.d/p3093.pdf.

Last reviewed: September 10, 2023

In experimentally infected nonhuman primates, HAV has been detected in saliva during the incubation period; however, transmission by human saliva has not been reported.

Last reviewed: June 25, 2023

While administration of Pentacel to a 5-year-old would be considered off-label and a vaccine administration error, the doses of DTaP and IPV can be counted as valid and do not need to be repeated. Hib vaccine is not routinely administered after a child has reached the age of 5 years so it is also a vaccine administration error. You should explain this error to the parents and assure them that the extra Hib dose will cause no harm.

Last reviewed: July 15, 2023

Having a pregnant person in a household, including the child’s mother, is not a contraindication to administration of any routinely recommended vaccine. Pregnant people should not have close contact with anyone who has recently (within the last 28 days) received the live, replication-competent smallpox vaccine (ACAM2000, Emergent Biosolutions).

Last reviewed: August 29, 2022

Whether these doses count as part of the child’s series depends on the intervals between these doses and the ones that preceded them. If the second MMR was separated from the previous one by at least 4 weeks, it can be counted as the second MMR. No additional doses are indicated. The 4th dose of IPV is recommended after the 4th birthday. In this case, the child would need a fifth dose of IPV on or after her fourth birthday. The fifth dose of DTaP should not be given earlier than age 4 years. Assuming this dose of DTaP was the fifth the child received, it was given too early and should not be counted. The DTaP should be repeated on or after the child’s fourth birthday.

Last reviewed: June 6, 2023

All significant health events that may have been related to a dose of vaccine, particularly those that lead to hospitalization, disability, or death, should be reported to VAERS. The healthcare provider doesn’t need to be certain the event was vaccine related in order to report it. It is not necessary to report minor adverse reactions, such as local reactions or low-grade fever.

Last reviewed: August 31, 2022

Unless rabies can be ruled out by diagnostic testing of the bat, rabies postexposure prophylaxis (PEP) is recommended. Because the details of these recommendations are fairly complex and depend on various factors, consultation with state and local health departments should be sought.

Last reviewed: May 14, 2023

The National Childhood Vaccine Injury Act requires that a VIS must be given to parents, legal representatives, or adult patients before administering the vaccine. A VIS must be provided prior to each dose, not just the first dose. Providers should be sure they are using the most current version of each VIS. Current VISs and their dates are available from on the CDC’s website at www.cdc.gov/vaccines/hcp/vis/index.html and from Immunize.org’s website at www.immunize.org/vis.

Last reviewed: June 6, 2023

The only way to meet the school entry deadline for a complete series by September would be to restart a primary series with Bexsero (MenB-4C), which requires two doses spaced at least 4 weeks apart. You must wait a minimum of 4 weeks after the Trumenba dose to initiate the Bexsero series.

Last reviewed: March 24, 2024

A buffered temperature probe is designed to prevent misleading and rapidly fluctuating readings by protecting the TMD from sudden changes in air temperature that can occur when opening a refrigerator door. A probe is “buffered” by immersing it in a vial filled with liquid (e.g., glycol, ethanol, glycerin), loose media (e.g., sand, glass beads), or a solid block of material such as Teflon or aluminum. Vaccine packaging is more thermostable than air because the temperature of solids and fluids change more slowly than air. Standard probes that measure air temperature can fluctuate with the defrost cycles of the unit, frequent opening and closing the door on busy workdays, air circulation patterns, etc. This could lead someone to inaccurately interpret changes in air temperature to mean that the vaccine temperature was out of range.

Last reviewed: July 26, 2023

All vaccines except the live, replication-competent smallpox vaccine (ACAM2000, Emergent Biosolutions) and yellow fever vaccine may be given to people who are breastfeeding.

ACAM2000 is contraindicated due to the theoretical risk of contact transmission of the vaccine virus from mother to child.

The only yellow fever (YF) vaccine licensed in the United States (YF-Vax, Sanofi) is contraindicated in people who are breastfeeding infants younger than 9 months of age. There have been three case reports of YF vaccine-associated encephalitis in infants under one month of age who were being exclusively breastfed at the time the mother received YF vaccine. ACIP currently recommends that people who are breastfeeding should be advised to postpone travel to YF endemic or epidemic regions; however, if travel cannot be avoided or postponed, the breastfeeding parent should receive YF vaccine. Although there are no data, some experts recommend that breastfeeding people who receive YF vaccine should temporarily suspend breastfeeding, pump, and discard pumped milk for at least 2 weeks after vaccination before resuming breastfeeding.

Last reviewed: August 29, 2022

A shared clinical decision-making (SCDM) recommendation is different from routine vaccine recommendations based simply on a person’s age or risk for disease. With routine vaccine recommendations the default decision is to vaccinate all persons in a specified age group or risk group. With SCDM recommendations, vaccination is not the default decision based on age or risk group alone: desirability will vary from person to person.

In the case of RSV vaccine, SCDM recommendations are informed by:

  • whether the patient has any risk factors for severe RSV disease,
  • the safety profile of the RSV vaccine products and the patient’s risk tolerance,
  • a patient’s preferences for prevention of RSV, and
  • the clinical discretion of the health care provider

In the judgment of ACIP members, both vaccines were well tolerated, and the safety profiles were generally acceptable. Six cases of inflammatory neurologic events were reported (including Guillain Barré syndrome and others) after RSV vaccination during clinical trials of the two licensed vaccines, but evidence was insufficient to determine whether these were due to chance or possibly caused by vaccine. Investigations continue into these findings and safety monitoring is ongoing to clarify whether or not there is any increased risk of these conditions associated with RSV vaccination. The ACIP SCDM recommendation is intended to provide flexibility for providers and vaccine recipients to take into account an individual’s risks for severe RSV disease and patient preference. Some will choose to defer vaccination until more is known about the vaccine’s performance or until their personal risk for severe RSV is greater.

CDC has a one-page resource for healthcare providers to assist in these SCDM conversations with patients: www.cdc.gov/vaccines/vpd/rsv/downloads/provider-job-aid-for-older-adults-508.pdf.

Last reviewed: January 22, 2024

All infants should be given a primary series of either PCV15 or PCV20, at ages 2, 4, and 6 months with a booster at age 12 to 15 months. Otherwise healthy children who fall behind should be given catch-up vaccination through age 59 months; if they have certain underlying medical conditions they should be given catch-up vaccination through age 71 months.

For pneumococcal vaccination of children ages 2 through 5 years, see the CDC summary here: www.cdc.gov/vaccines/vpd/pneumo/hcp/who-when-to-vaccinate.html#children-2-5.

Immunize.org offers a print-ready clinical resource that addresses pneumococcal vaccination recommendations for all children, including those with any relevant health condition or incomplete vaccination history, entitled Recommendations for Pneumococcal Vaccines Use in Children and Teens: www.immunize.org/wp-content/uploads/catg.d/p2016.pdf.

Last reviewed: April 5, 2024

People who do not have a functioning spleen or who have had a splenectomy are at increased risk for infection with encapsulated bacteria, especially Pneumococcus, Neisseria meningitidis, and Haemophilus influenzae type b (Hib).

In addition to receiving routine vaccinations, children and adults without a functioning spleen who are age 2 years and older need additional pneumococcal vaccinations, with specific recommendations dependent on an individual’s age and specific pneumococcal vaccination history. Refer to current immunization schedules, Immunize.org’s standing orders templates for pneumococcal vaccination, or CDC’s PneumoRecs VaxAdvisor Mobile App.

All asplenic people should receive a primary series of at least 2 doses of meningococcal ACWY vaccine (MenACWY) with a booster dose every 5 years. See the MenACWY recommendation table at www.immunize.org/catg.d/p2018.pdf for details. Asplenic people age 10 years and older should also receive a series (either 2 or 3 doses depending on the vaccine brand) of meningococcal serogroup B vaccine (MenB) with an initial booster dose one year after completion of the primary series and subsequent booster doses every 2–3 years thereafter. A pentavalent MenABCWY vaccine (Penbraya, Pfizer) is also an option in certain circumstances.

Two doses of Hib vaccine should be given to unimmunized children 12–59 months of age (defined as a child who received zero or 1 dose before 12 months of age). A single dose of Hib vaccine should be administered to unimmunized people age 5 years or older (defined as those who have not received at least 1 dose of Hib vaccine after 14 months of age).

Last reviewed: April 10, 2024

MMR vaccine given within 72 hours of initial measles exposure can reduce the risk of getting sick or reduce the severity of symptoms. Another option for exposed, measles-susceptible individuals at high risk of complications who cannot be vaccinated is to give immunoglobulin (IG) within six days of exposure. Do not administer MMR vaccine and IG simultaneously, as the IG invalidates the vaccine.

Information on post-exposure prophylaxis for measles can be found in the 2013 ACIP guidance at www.cdc.gov/mmwr/pdf/rr/rr6204.pdf, page 24.

Last reviewed: June 19, 2023

No. The vaccine series need not be restarted if more than 6 months have elapsed since the first dose.

Last reviewed: March 9, 2022

For most people who need only 1 dose of influenza vaccine, vaccination should ideally be offered in September and October. For people not vaccinated by the end of October, vaccination efforts should continue as long as influenza viruses are circulating and unexpired vaccine is available.

Vaccination in July and August should be avoided for most groups unless there is concern that vaccination later in the season might not be possible. Early vaccination has been associated with waning of vaccine-induced immunity and decreased vaccine effectiveness before the end of the influenza season, particularly among older adults.

Vaccination in July and August may be considered for people in their third trimester of pregnancy, to allow time for protective maternal antibodies to transfer to the fetus, providing protection during early infancy. Children younger than age 9 years who need two doses of vaccine this season should receive their first dose as soon as possible so that they can get their second dose before the end of October. Children who need only one dose can be considered for vaccination in July or August.

Last reviewed: September 10, 2023

For the general public, only one HepB series is routinely recommended in a lifetime, with specific exceptions described below.

As of April 2022, CDC recommends HepB vaccination of the following:

  • Routine HepB vaccination of all infants, beginning with a birth dose.
  • Routine HepB vaccination of all children and adults through age 59 years.
  • Vaccination of all adults age 60 years and older with risk factors for hepatitis B:
    • People at risk for infection by sexual exposure
      • Sex partners of people testing positive for HBsAg
      • Sexually active people who are not in a long-term, mutually monogamous relationship (e.g., those with more than one sex partner during the previous 6 months)
      • People seeking evaluation or treatment for a sexually transmitted infection
      • Men who have sex with men
    • People at risk for infection by percutaneous or mucosal exposure to blood
      • People with current or recent injection drug use
      • Household contacts of people testing positive for HBsAg
      • Residents and staff members of facilities for people with developmental disabilities
      • Health care and public safety personnel with reasonably anticipated risk for exposure to blood or blood-contaminated body fluids
      • People on maintenance dialysis, including in-center or home hemodialysis and peritoneal dialysis, and people who are predialysis
      • People with diabetes, at the discretion of the treating clinician
    • Others
      • International travelers to countries with high or intermediate levels of endemic HBV infection (HBsAg prevalence of 2% or higher)
      • People with hepatitis C virus infection
      • People with chronic liver disease (including, but not limited to, people with cirrhosis, fatty liver disease, alcoholic liver disease, autoimmune hepatitis, and an alanine aminotransferase or aspartate aminotransferase level greater than twice the upper limit of normal)
      • People with HIV infection
      • People who are incarcerated
  • Adults age 60 or older years without known risk factors for hepatitis B infection may receive HepB.

People with documentation of complete vaccination or documentation of previous HBV infection generally do not need to be vaccinated; however, there is no evidence that administration of additional doses of HepB to someone who is already immune or infected is harmful. Serologic testing is not required before vaccination and should not pose a barrier to access to vaccination. If testing is done, it may be done at the same visit when the first dose of vaccine is administered.

Revaccination is recommended only for individuals for whom post-vaccination serologic testing (PVST) is recommended and evidence of nonresponse is found. Annual serologic testing of people undergoing dialysis is recommended, with booster doses administered when detectable antibodies drop below 10 mIU/mL. Annual testing and revaccination may be indicated for other immunocompromised people. See CDC 2018 ACIP recommendations for a detailed discussion of these issues: www.cdc.gov/mmwr/volumes/67/rr/pdfs/rr6701-H.pdf (pages 21-24).

Last reviewed: July 21, 2023

Moderna COVID-19 Vaccine has two updated (2023–2024 Formula) presentations. CDC has summarized basic information about the different presentations and their storage, preparation, and administration in its Moderna COVID-19 vaccine at-a-glance document available here: www.cdc.gov/vaccines/covid-19/info-by-product/moderna/downloads/vaccine-at-a-glance.pdf.

Vaccinators who stock multiple presentations should check three times to confirm that they are administering the proper product with the proper dose and dose volume for each patient.

Last reviewed: March 19, 2024

Try to follow general guidelines for oral administration of liquid vaccines. First, give this vaccine at the beginning of the office visit, while the baby is still happy, and before you administer injections or perform other procedures. Second, make every effort to aim the dropper containing the vaccine down one side and toward the back of the child’s mouth. Don’t put the dropper so far back that you gag the child. You may find the following information from the RotaTeq manufacturer helpful: www.merckvaccines.com/Products/RotaTeq/Pages/dosageandadministration. You can also find a pictorial description of both reconstitution and administration of the lyophilized formulation of Rotarix at www.rotarixhcp.com/dosage/administration/.

Last reviewed: June 7, 2023

Immunize.org has prepared a document that provides a summary of the ACIP recommendations for use of MenACWY for people of all ages. The document is available at www.immunize.org/catg.d/p2018.pdf.

Last reviewed: March 24, 2024

No. There is no screening laboratory test that can determine whether a person is already immune or still susceptible to any given HPV type. Most sexually active adults have been exposed to one or more HPV types, although not necessarily all of the HPV types targeted by vaccination. HPV vaccine works to prevent infection with vaccine types to which a person is still susceptible.

Last reviewed: March 2, 2024

Limited data suggest that Hib vaccine given before 6 weeks of age may induce immunologic tolerance to Hib antigen and reduce the response to subsequent doses. As a result, Hib vaccine should not be given earlier than 6 weeks of age. However, if a dose was administered before 6 weeks of age, it should not be counted as part of the Hib series. A full series of 3 or 4 doses, depending on the product used, should be started at 2 months of age as usual. No special protocol or testing is recommended for children who received a dose of Hib vaccine before 6 weeks of age.

Last reviewed: July 31, 2022

CDC recommends that Dengvaxia should be used with precaution in breastfeeding individuals. There are no data in humans to evaluate the safety of Dengvaxia in infants who are breastfed. Providers and breastfeeding parents should weigh the benefits of breastfeeding and the risk of DENV infection in the mother and the infant.

Last reviewed: February 16, 2022

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.

Last reviewed: December 28, 2022

As of January 2020, ACIP recommends that Td or Tdap may be administered in any situation when only Td vaccine was previously recommended. Someone who received a dose of Tdap at age 11 or 12 years should receive a booster dose of Td or Tdap vaccine ten years later, unless tetanus prophylaxis is required sooner due to an injury or if Tdap vaccination is needed during pregnancy.

Last reviewed: March 31, 2022

If the child had confirmed varicella disease or laboratory evidence of prior disease, it is not necessary to vaccinate regardless of age at infection. If there is any doubt that the illness was actually varicella, the child should be vaccinated.

Last reviewed: May 16, 2023

Hospital-acquired HAV infection is rare. In the past, outbreaks were observed in neonatal intensive care units when infants acquired infection from HAV-infected transfused blood and subsequently transmitted HAV to other infants and staff. Outbreaks of hepatitis A caused by transmission from adult patients to healthcare personnel (HCP) are typically associated with fecal incontinence and inadequate hand hygiene, although the majority of hospitalized patients who have hepatitis A are admitted after onset of jaundice, when they are beyond the point of peak infectivity. Transmission in healthcare settings also has resulted from breakdowns in standard infection control practices and transmission from one healthcare provider to another.

Last reviewed: June 25, 2023

No. CDC recommends that every vaccine storage unit must have its own TMD. An accurate temperature history that reflects actual vaccine temperatures is critical for protecting your vaccines. It is also recommended to have at least one backup TMD on site in case a primary device breaks or malfunctions.

Last reviewed: July 26, 2023

Influenza vaccine and Td (or Tdap) may be given at the same time or at any time before or after a dose of pneumococcal polysaccharide vaccine. The only time you have to wait is when two LIVE vaccines are not given at the same visit; then you need to wait at least 4 weeks to give the second live vaccine.

Last reviewed: June 6, 2023

The National Vaccine Injury Compensation Program (NVICP) includes payment only for injuries determined to have occurred following vaccination with a vaccine routinely recommended for children or pregnant women in the United States. The recipient can be of any age, but the vaccine must be routinely recommended for children through age 18 years or pregnant women. The vaccine must be subject to an excise tax to be included in the program. Shingrix and PPSV23 vaccines are not routinely recommended for children or pregnant women; Shingrix is only recommended for adults. COVID-19 vaccines will transition from injury compensation coverage under the Countermeasure Injury Compensation Program to NVICP once criteria are met for inclusion in NVICP. More information about the program and the covered vaccines is at www.hrsa.gov/vaccine-compensation/covered-vaccines/index.html.

Last reviewed: August 31, 2022

Instructions on the use of VISs and many additional items are available on the CDC website at www.cdc.gov/vaccines/hcp/vis/index.html or from your state immunization program. You can also visit Immunize.org’s website at www.immunize.org/vis for links to many important documents about the use of VISs.

Last reviewed: June 6, 2023

The patient can complete the series with either vaccine. If Bexsero (MenB-4C) is chosen, the second and final dose should be administered at least 1 month after yesterday’s dose. If Trumenba (MenB-FHbp) is chosen and the patient is healthy (i.e., does not have a high-risk condition for meningococcal B disease such as asplenia), the second and final dose of Trumenba should be administered at least 4 months after yesterday’s Bexsero dose (6 months after the first Trumenba dose). If the person is at increased risk for meningococcal B disease and Trumenba is being used, a second Trumenba dose should be administered 1 month after yesterday’s Bexsero dose and a third dose should be administered 4 months after the second Trumenba dose.

Last reviewed: March 24, 2024

It may take 2 to 7 days to stabilize the temperature in a newly installed or repaired refrigerator or 2 to 3 days for a freezer. Before using a unit for vaccine storage, check and record the minimum and maximum temperatures each workday for two to seven days. If temperatures cannot be recorded using a continuous digital data logger, check and record temperatures a minimum of two times each workday. Once you have two consecutive days of temperatures recorded within the recommended range, your unit is stable and ready for use. Recommended temperatures are between 2°C and 8°C (36°F and 46°F) for the refrigerator and between -50°C and -15°C (-58°F and +5°F) for the freezer.

Last reviewed: July 26, 2023

Document the discussion and reason for deferral in the medical record. Because the risk of severe disease increases with age, plan to revisit the decision periodically to vaccinate once the patient’s risk-benefit assessment shifts in favor of vaccination.

Last reviewed: January 22, 2024

The conditions that increase the risk of pneumococcal disease and are indications for additional pneumococcal vaccine doses beyond the routine schedule are broken down into two categories: non-immunocompromising (non-IC) and immunocompromising (IC). Recommendations differ slightly under certain circumstances by IC or non-IC category.

Non-IC conditions include:

  • Cerebrospinal fluid (CSF) leak
  • Chronic heart disease (especially cyanotic congenital heart disease and heart failure)
  • Chronic kidney disease (except as specified in the IC list below)
  • Chronic liver disease
  • Chronic lung disease (including moderate persistent or severe persistent asthma)
  • Diabetes mellitus
  • Cochlear implant

Immunocompromising (IC) conditions include:

  • Kidney disease and on maintenance dialysis
  • Kidney disease with nephrotic syndrome
  • Asplenia or splenic dysfunction
  • Congenital or acquired immunodeficiency, including B-(humoral) or T-lymphocyte deficiency; complement deficiencies, particularly C1, C2, C3, and C4 deficiency; and phagocytic disorders (excluding chronic granulomatous disease)
  • Treatment with immunosuppressive drugs or radiation therapy (including treatment for Hodgkin disease, leukemias, lymphomas, malignant neoplasm, and solid organ transplant)
  • HIV infection
  • Sickle cell disease or other hemoglobinopathies

An older child through age 18 years with any high-risk condition who completed a pneumococcal conjugate series before age 6 years that included any dose of PCV20, is not recommended to receive any additional PCV doses.

Children with IC or non-IC conditions who completed a PCV series before age 6 years with PCV13 or PCV15 (but who have not received PCV20 or pneumococcal polysaccharide vaccine [PPSV23]) should receive additional pneumococcal vaccination with a single dose of PCV20 at least 8 weeks after the most recent PCV dose. If PCV20 is not available, a non-IC or IC child in this circumstance may, alternatively, receive a single dose of PPSV23 at least 8 weeks after the most recent PCV dose. An IC child given PPSV23 in this circumstance would also be due for a dose of either PCV20 or a second dose of PPSV23 at least 5 years after the first PPSV23.

Doses of the 7-valent PCV (the original Prevnar, PCV7) do not count toward PCV vaccination when determining the current pneumococcal vaccination needs of a child or teen with a qualifying non-IC or IC condition.

When feasible, administer any needed pneumococcal vaccination at least two weeks before initiating planned interventions that place a child at high risk (such as a cochlear implant or spleen removal).

Immunize.org details all recommendations and options for children with high-risk conditions in its standing order template for pneumococcal vaccination of children and teens (www.immunize.org/wp-content/uploads/catg.d/p3086.pdf) and its shorter resource, Recommendations for Pneumococcal Vaccines use in Children and Teens (www.immunize.org/wp-content/uploads/catg.d/p2016.pdf).

For a complete explanation of pneumococcal vaccination recommendations for ages 6 through 18 years, CDC has summarized the recommendations here: www.cdc.gov/vaccines/vpd/pneumo/hcp/who-when-to-vaccinate.html#children-6-18.

Last reviewed: April 5, 2024

No. Adults with evidence of immunity do not need any further vaccines. No “booster” doses of MMR vaccine are recommended for either adults or children. They are considered to have life-long immunity once they have received the recommended number of MMR vaccine doses or have other evidence of immunity.

Last reviewed: June 19, 2023

Complete the series based on shared clinical decision-making involving the patient’s risk and desire for protection.

Last reviewed: March 2, 2024

No.

Last reviewed: March 9, 2022

CDC and ACIP make no recommendation for revaccination later in the season of people who have been fully vaccinated for the season, regardless of when the current season vaccine was received.

Last reviewed: September 10, 2023

All current and recent past ACIP recommendations concerning hepatitis B vaccination are available at: www.cdc.gov/vaccines/hcp/acip-recs/vacc-specific/hepb.html.

The most recent recommendations for adult HepB vaccination were published in MMWR on April 1, 2022. This publication details the routine catch-up recommendation for HepB vaccination of all adults age 19 through 59 years. The document is available at www.cdc.gov/mmwr/volumes/71/wr/pdfs/mm7113a1-H.pdf.

The 2018 comprehensive ACIP HepB recommendations publication contains detailed guidance on pediatric vaccination, post-vaccination serologic testing of healthcare professionals and other select high risk individuals, as well as the prevention of mother-to-child transmission of hepatitis B. It is available at www.cdc.gov/mmwr/volumes/67/rr/pdfs/rr6701-H.pdf.

In addition to the published recommendations, CDC has produced a frequently asked questions page for HBV infection and HepB vaccination: www.cdc.gov/hepatitis/hbv/hbvfaq.htm.

Last reviewed: August 19, 2023

Both the Pfizer-BioNTech COVID-19 Vaccine and the Moderna COVID-19 Vaccine are lipid nanoparticle-formulated, nucleoside-modified mRNA vaccines encoding the prefusion spike glycoprotein of SARS-CoV-2, the virus that causes COVID-19. The 2023–2024 formula targets the Omicron XBB.1.5 sublineage of the spike protein. Visit this CDC website for more details about how mRNA vaccines work: https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/how-they-work.html.

Last reviewed: March 19, 2024

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