Ask the Experts: All Questions

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Results (1317)

All immunocompetent people age 50 years or older-whether they have a history of chickenpox or shingles or not-should be given Shingrix unless they have a medical contraindication to vaccination. Among this population it is not necessary to ask about a history of chickenpox or to test for varicella antibody prior to or after giving the vaccine.

Among immunocompromised people age 19 years or older, evidence of a history of varicella illness or varicella vaccination (confirming the need for Shingrix as a result of a history of exposure to a live varicella virus, whether the wild or live-attenuated vaccine strain) IS recommended. Shingrix may be administered to an immunocompromised person who has had chickenpox or shingles or has previously been vaccinated with varicella vaccine or zoster vaccine live. See the Immunocompromised Adults section for additional information about partially-vaccinated immunocompromised adults with no history of chickenpox.

Last reviewed: March 9, 2022

Heplisav-B (Dynavax) was approved by the Food and Drug Administration (FDA) in November 2017 for people 18 years of age and older. Heplisav-B contains a novel adjuvant (CpG 1018) that binds to Toll-like receptor 9 to stimulate the immune response to HBsAg. It is provided in a single dose 0.5 mL vial and given as a 2-dose series with doses separated by 1 month (4 weeks).

Heplisav-B was approved based on clinical trials that compared seroprotection rates (SPR, defined as anti-HBs of 10 mIU or higher, and indicative of protection against hepatitis B infection) following 2 doses of Heplisav-B to rates following 3 doses of Engerix-B (GSK). Among people 18 through 70 years of age, SPRs were 90%–95% following 2 doses of Heplisav-B and 65%–81% following 3 doses of Engerix-B. Local reactions were most commonly reported (injection site pain, redness, and swelling) and were similar in frequency to those following Engerix-B.

The package insert for Heplisav-B is available here: www.fda.gov/media/108745/download.

Last reviewed: July 21, 2023

In the 2013 revision of its MMR vaccine recommendations ACIP includes laboratory confirmation of disease as evidence of immunity for measles, mumps, and rubella. ACIP removed physician diagnosis of disease as evidence of immunity for measles and mumps. Physician diagnosis of disease had not previously been accepted as evidence of immunity for rubella. With the decrease in measles and mumps cases over the last 30 years, the validity of physician-diagnosed disease has become questionable. In addition, documenting history from physician records is not a practical option for most adults. The 2013 MMR ACIP recommendations are available at www.cdc.gov/mmwr/pdf/rr/rr6204.pdf.

Last reviewed: June 19, 2023

No. The last U.S. doses of Janssen COVID-19 Vaccine expired May 7, 2023.

Last reviewed: March 19, 2024

In 2018, FDA licensed Vaxelis for use in children age 6 weeks through 4 years: it is indicated as a 3-dose series for infants at ages 2, 4, and 6 months. ACIP voted to add Vaxelis to the Vaccines for Children (VFC) Program in 2019.

The MSP Vaccine Company was created as a joint venture between Merck and Sanofi Pasteur to produce Vaxelis. Vaxelis contains the same DTaP components as Pentacel (Sanofi Pasteur). The IPV component is the same as IPOL (Sanofi Pasteur). The Hib component is the same as PedvaxHIB (Merck), but in a decreased amount. The HepB component is the same as the pediatric formulation of Recombivax HB (Merck), but in an increased amount. Vaxelis is a liquid vaccine that does not require reconstitution.

The complete recommendations for the use of Vaxelis are available at: www.cdc.gov/mmwr/volumes/69/wr/pdfs/mm6905a5-H.pdf.

Last reviewed: July 15, 2023

Yellow fever is contraindicated for people who have a history of a severe (anaphylactic) allergy to eggs.

ACIP and CDC no longer consider egg allergy of any severity to be a contraindication or precaution to egg-based influenza vaccines. A person with egg allergy of any severity may receive any influenza vaccine that is appropriate for the person’s age and health status. When administering an egg-based influenza vaccine to a person with egg allergy of any severity, no additional safety precautions are needed, beyond those recommended when administering any vaccine to any recipient.

For more details about giving influenza vaccine to people with a history of egg allergy, go to www.cdc.gov/vaccines/hcp/acip-recs/vacc-specific/flu.html for a link to the current ACIP recommendations for influenza vaccination.

Last reviewed: September 19, 2022

Pregnant people between 32 and 36 weeks and 6 days’ gestation during the months of September through January in the United States should get one dose of the Pfizer RSVpreF vaccine (Abrysvo) to protect their babies during their first RSV season after birth. Only Abrysvo is FDA-approved and recommended for pregnant people. Arexvy (by GSK) is not approved and should not be given during pregnancy.

In most of the continental United States, maternal RSV vaccine is recommended only September through January. Those who provide health care to pregnant people who live in areas with different patterns of RSV seasonality, such as Alaska, Hawaii, parts of Florida, or other jurisdictions outside the continental United States, should follow guidance from local or regional public health authorities about the timing of RSV vaccination during pregnancy in their regions.

Last reviewed: January 22, 2024

Yes. Rotavirus vaccine virus is shed during the first weeks after administration of rotavirus vaccine. Handwashing after diaper changing is always recommended.

Last reviewed: June 7, 2023

Yes. If different brands of Hib vaccine are given at 2 and 4 months of age then the child should receive a third primary dose of either vaccine at 6 months of age. A 2-dose primary schedule (that is, doses at age 2 and 4 months) is only appropriate when both doses are PedvaxHIB.

Last reviewed: July 31, 2022

ACIP does not address the use of this method for vaccination in its “Best Practices Guidelines for Immunization” (www.cdc.gov/vaccines/hcp/acip-recs/general-recs/administration.html). If you choose to use this method, you should still adhere to the ACIP’s recommendations regarding needle length and anatomical site.

Last reviewed: December 28, 2022

Your solution will meet the spirit of the federal law, as long as you make sure to encourage the patient (or parent) to take home a paper copy of the VIS and to refer to it if needed (e.g., if they need to know what to do if there is an adverse event or how to contact VAERS).

Last reviewed: June 6, 2023

Yes. In its 2018 recommendations for the prevention of herpes zoster, ACIP states that Shingrix may be used in adults age 50 years or older irrespective of prior receipt of varicella vaccine or live zoster vaccine (Zostavax, Merck). Shingrix is also recommended for adults age 19 and older who are immunocompromised due to disease or treatment if they have a history of varicella illness or vaccination.

Last reviewed: May 16, 2023
Recommended dosages and schedules of hepatitis A vaccines
Vaccine Age group Dose Volume # Doses Schedule
Havrix
(GSK)		 1–18 years 720 El.U.* 0.5 ml 2 0, 6–12 mos.
19 years and older 1440 El.U.* 1.0 ml 2 0, 6–12 mos.
Vaqta
(Merck & Co.)		 1–18 years 25 U** 0.5 ml 2 0, 6–18 mos.
19 years and older 50 U** 1.0 ml 2 0, 6–18 mos.

*El.U. = Elisa Units **U = Units

 

Combination vaccine using hepatitis A and hepatitis B vaccines
Vaccine Age group Antigens used Volume # Doses Schedule
Twinrix
(GSK)		 18 years and older Havrix (720 El.U.)
combined with
Engerix-B (20 mcg)		 1.0 ml 3 0, 1, 6 mos.
4 0, 7, 21-30 days, 12 months**

** Accelerated schedule may be used for rapid protection prior to travel or for rapid protection of an unexposed but at-risk person who also would benefit from hepatitis B protection. Twinrix is not recommended for use as post-exposure prophylaxis.

Last reviewed: June 25, 2023

Healthcare providers should vaccinate any person who failed to get vaccinated in the previous vaccination season and who wants to reduce their risk of getting influenza during their upcoming travel, particularly if they are at high risk for influenza-related complications. This includes people who are traveling to the tropics, traveling with organized tourist groups at any time of year, or traveling to the Southern Hemisphere during April–September.

Last reviewed: September 10, 2023

No. IgM tests for acute DENV infection are not sufficiently accurate to be acceptable evidence for the purposes of vaccination. These tests may be falsely positive as a result of other flavivirus infections that may cause similar symptoms (such as Zika).

Acceptable evidence of acute infection with DENV is either a positive dengue RT-PCR test result, or a positive dengue NS1 antigen test result.

Visit CDC’s website on laboratory testing requirements for vaccination with Dengvaxia for additional information: www.cdc.gov/dengue/vaccine/hcp/testing.html.

Last reviewed: February 16, 2022

If the first dose is given at age 13 through 15 years, you can give the booster dose as early as age 16 years, with a minimum interval of 8 weeks from the previous dose. So even if the patient was vaccinated at age 15 years 11 months, you could wait at least 8 weeks and then give the booster at age 16 years 1 month (or later).

Last reviewed: March 24, 2024

Allergy to egg is not a contraindication for MMR vaccine. Although measles and mumps vaccines are grown in chick embryo tissue culture, several studies have documented the safety of these vaccines in children with severe egg allergy.

Last reviewed: August 29, 2022

Vaccines from your supply should not be routinely transported. In instances where the transport of vaccine from your supply is necessary, take appropriate precautions to protect your supply. Vaccines should only be transported using appropriate packing and temperature monitoring materials that provide the maximum protection. CDC provides detailed guidance on the transport of vaccines in the Storage and Handling Toolkit, pages 23–26 at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf. See the addendum of the Toolkit for additional instructions concerning COVID-19 and mpox vaccines.

Last reviewed: July 26, 2023

No. Only the Pfizer (Abrysvo) RSV vaccine is recommended for pregnant people. The GSK RSV vaccine (Arexvy) is not licensed or recommended for use in pregnancy.

If Arexvy is inadvertently administered during pregnancy, do NOT administer a dose of Abrysvo. Instead, CDC recommends that the infant (if younger than 8 months) should receive nirsevimab during RSV season (October through March in most of the continental United States). Treat the infant in the same manner as an infant born to a mother who did not receive RSV vaccination during pregnancy.

CDC strongly urges that this type of administration error be reported to the Vaccine Adverse Event Reporting System, VAERS (https://vaers.hhs.gov). Prevent administration errors with health care provider training on the different indications for each RSV prevention product (both vaccines and the nirsevimab preventive antibody for infants), and always check product labels at least three times before administration to verify that the correct product is being administered to the patient. Consider implementing other feasible safeguards in your system (e.g., electronic alerts) to prevent such errors.

For additional information about this type of error, see the CDC Clinician Outreach and Communication Activity (COCA) Now update from January 22, 2024:  https://emergency.cdc.gov/newsletters/coca/2024/012224.html

Last reviewed: January 22, 2024

VISs are required to be given and documented when any vaccine covered by the National Childhood Vaccine Injury Act (NCVIA) is given to a person of any age in any setting, including influenza vaccine. CDC recommends that VISs should be given and documented any time any vaccine is administered, regardless of the recipient’s age and setting.

Current VISs are available from the CDC’s website at www.cdc.gov/vaccines/hcp/vis/index.html and from the Immunize.org website at www.immunize.org/vaccines/vis-translations/spanish/, where you will also find many VIS translations in other languages.

Last reviewed: April 10, 2024

Measles vaccine, given as MMR, may be effective if given within the first 3 days (72 hours) after exposure to measles. Immune globulin may be effective for as long as 6 days after exposure. Postexposure prophylaxis with MMR vaccine does not prevent or alter the clinical severity of mumps or rubella. However, if the exposed person does not have evidence of mumps or rubella immunity they should be vaccinated since not all exposures result in infection.

Last reviewed: June 19, 2023

No. Currently no data exist to indicate that people younger than 19 who smoke are at increased risk of pneumococcal disease.

Last reviewed: April 5, 2024

A person who has never been exposed to varicella virus through infection or vaccination with varicella vaccine or zoster vaccine live is not at risk for shingles. Shingrix has not been evaluated for the prevention of primary infection with varicella virus. People who have never had chickenpox are recommended to receive 2 doses of varicella vaccine.

Serologic studies indicate that about 99% of people born before 1980 worldwide have had chickenpox even though many cannot recall having had chickenpox (www.cdc.gov/mmwr/preview/mmwrhtml/rr5705a1.htm). As a result, there is no need to ask immunocompetent people age 50 years and older for their varicella disease history or to perform a laboratory test for serologic evidence of prior varicella disease.

Immunocompromised adults age 19 years and older without evidence of exposure to live varicella virus through a history of chickenpox, zoster, or documentation of vaccination with live varicella vaccine (Varivax or ProQuad, Merck) or zoster vaccine live (Zostavax, Merck) should be evaluated further. Birth before 1980 is not sufficient proof of immunity for immunocompromised adults. For immunocompromised adults, evidence of immunity to varicella (confirming need for RZV) includes:

  • Documentation of two doses of varicella vaccine, or
  • Laboratory evidence of immunity or laboratory confirmation of disease, or
  • Diagnosis or verification of a history of varicella or herpes zoster by a healthcare provider.

For any adult who is clinically determined to be susceptible to primary varicella infection, refer to the ACIP varicella vaccine recommendations for further guidance, including post-exposure prophylaxis guidance for immunocompromised adults: www.cdc.gov/mmwr/preview/mmwrhtml/rr5604a1.htm.

CDC has published clinical considerations for shingles vaccination of immunocompromised patients who lack evidence of immunity to chickenpox: www.cdc.gov/shingles/vaccination/immunocompromised-adults.html#special-populations.

Last reviewed: March 9, 2022

PreHevbrio (VBI) was approved by the FDA in November 2021 for people age 18 years and older. It is a triple-antigen (containing S, Pre-S1, and Pre-S2 HBV surface proteins) recombinant vaccine produced in mammalian cells (Chinese hamster ovary cells), and containing an alum adjuvant. It is given intramuscularly in a 3-dose series of 1.0 mL (10 mcg) doses administered on a 0-, 1-, and 6-month schedule. The most common side effects of vaccination are injection site pain and tenderness, as well as fatigue, muscle aches, and headache.

PreHevbrio was approved based on clinical trials conducted in adults age 18 years and older that compared seroprotection rates (SPR, defined as anti-HBs of 10 mIU or higher, and indicative of protection against HBV infection) following 3 doses of PreHevbrio to rates following 3 doses of Engerix-B (GSK). The SPR for PreHevbrio among adults age 18 years or older ranged from 83.6% to 99.2% (overall, 91.2% for all adults) compared to Engerix-B, which ranged from 64.7% to 91.1% (overall, 76.5% for all adults).

PreHevbrio was included as an option for HepB vaccination of adults age 18 years or older in the current ACIP recommendations published on April 1, 2022: www.cdc.gov/mmwr/volumes/71/wr/pdfs/mm7113a1-H.pdf.

The package insert for PreHevbrio is available here: www.fda.gov/media/154561/download.

Last reviewed: July 21, 2023

Yes. The 2020 ACIP recommendations for MenB include a booster dose schedule for MenB vaccination of people at high risk for meningococcal serogroup B disease. The first booster dose is recommended one year after completion of the primary series, with a subsequent booster dose administered every 2–3 years thereafter, as long as risk remains. Because MenB vaccine brands are not interchangeable, all doses, including booster doses, should be of the same MenB brand. If the brand of the primary series is not known or not available, CDC recommends restarting the primary series with the available product.

Penbraya (MenABCWY, Pfizer) contains MenB-Fhbp (Trumenba) and is given as two doses, 6 months apart, when vaccination against all 5 serogroups is needed. For this 11-year-old child at increased risk of meningococcal disease, Penbraya may be used for MenACWY and MenB (Trumenba) doses (including booster doses) if both vaccines would be given on the same clinic day and at least 6 months have elapsed since the most recent Penbraya dose.

Last reviewed: March 24, 2024

Do not give rotavirus vaccine to an infant who has a history of a severe allergic reaction (for example, anaphylaxis) after a previous dose of rotavirus vaccine or to a vaccine component. The oral applicator for Rotarix contains natural latex rubber so infants with a severe (anaphylactic) allergy to latex should not be given Rotarix; the RotaTeq (Merck) dosing tube is latex-free. Rotavirus vaccine is contraindicated in infants with the rare disorder severe combined immunodeficiency (SCID) and in infants with a history of intussusception.

Practitioners should consider the potential risks and benefits of administering rotavirus vaccine to infants with known or suspected altered immunocompetence, including those whose mothers received immunosuppressive biologics (such as infliximab) during pregnancy. Consultation with an immunologist or infectious diseases specialist is advised.

Children and adults who are immunocompromised because of congenital immunodeficiency, hematopoietic stem cell transplantation, or solid organ transplantation sometimes experience severe or prolonged rotavirus gastroenteritis. However, few safety or efficacy data are available for the administration of rotavirus vaccine to infants who are immunocompromised or potentially immunocompromised, including 1) infants with primary and acquired immunodeficiency, cellular immunodeficiency, and hypogammaglobulinemia and dysgammaglobulinemia; 2) infants with blood dyscrasias, leukemia, lymphomas, or other malignant neoplasms affecting the bone marrow or lymphatic system; 3) infants on immunosuppressive therapy (including high-dose systemic corticosteroids); and 4) infants who are HIV-exposed or infected.

Last reviewed: June 7, 2023

Hib invasive disease does not always result in development of protective antibody levels. Children younger than 24 months of age who develop invasive Hib disease should be considered susceptible and should receive Hib vaccine. Vaccination of these children should start as soon as possible during the convalescent phase of the illness. A complete series as recommended for the child’s age should be administered.

Last reviewed: July 31, 2022

Both IM and SC vaccines may be given through a tattoo.

Last reviewed: December 28, 2022

There are two basic products that can be used in children younger than age 7 years (DTaP and DT) and two that can be used in older children and adults (Td and Tdap). Some people get confused between DTaP and Tdap and others get confused between DT and Td. Here’s a hint to help you remember. The pediatric formulations usually have 3–5 times as much of the diphtheria component than what is in the adult formulation. This is indicated by an upper-case “D” for the pediatric formulation (i.e., DTaP, DT) and a lower case “d” for the adult formulation (Tdap, Td). The amount of tetanus toxoid in each of the products is equivalent, so it remains an upper-case “T.”

Last reviewed: March 31, 2022

A mild case of chickenpox produces immunity to varicella as does a moderate or severe case. A child with a reliable history of chickenpox does not need to receive varicella vaccine. However, if there is any doubt that the mild illness really was chickenpox, it is best to vaccinate the child. There is no harm in vaccinating a child who is already immune.

Last reviewed: May 16, 2023

Yes, a number of studies indicate that the two brands of HepA, Havrix (GSK) and Vaqta (Merck), are interchangeable.

Last reviewed: June 25, 2023

There should be a minimum of 4 weeks between the doses in such situations.

Last reviewed: September 10, 2023

Yes. Vaxelis may be used for children younger than age 5 years requiring a catch-up primary series, using appropriate minimum intervals. It is not approved as the booster dose of DTaP [dose 4 or 5] or IPV [dose 4] or Hib [dose 4]. If Vaxelis is inadvertently given as a booster dose, it may count as valid and does not need to be repeated.

Last reviewed: July 15, 2023

Patients with a negative test should be re-tested every 1 or 2 years (while remaining between the ages of 9 through 16 years) or based on the clinical judgment of the health care provider.

CDC recommends that children and adolescents who are acutely ill with dengue virus infection should wait at least 6 months after the date dengue virus infection is confirmed to begin the vaccine series. https://www.cdc.gov/dengue/hcp/vaccine/schedule-dosing.html.

Last reviewed: February 16, 2022

Menveo is approved for adults through age 55 years. MenQuadfi was approved in 2020 for ages 2 years and older. If MenACWY is indicated for a person older than age 55 and you do not have MenQuadfi, use Menveo. If meningococcal B vaccination with MenB-FHbp (Trumenba) is needed at the same visit, Penbraya (MenABCWY, Pfizer) is also an option, as long as it has been at least 6 months since the most recent dose of Penbraya.

Last reviewed: March 24, 2024

The “two-vial” formulation of Menveo (MenACWY-CRM, GSK) requires reconstitution of a lyophilized powder with a diluent: it is FDA-licensed for administration to individuals age 2 months through 55 years. The “one-vial” liquid formulation of Menveo licensed in 2022 is essentially the same vaccine, but does not require reconstitution before administration; however, this formulation is currently licensed only for administration to people age 10 through 55 years.

If the “one-vial” formulation is inadvertently administered to a child younger than age 10 years, this incident should be reported to the Vaccine Adverse Event Reporting System (VAERS, https://vaers.hhs.gov) as a vaccine administration error; however, the dose may be counted as valid and should not be repeated. If your facility stocks both one-vial and two-vial Menveo formulations, review practices and protocols and ensure clear labeling of vaccines in storage units to minimize the risk of administering the one-vial formulation to a child younger than age 10 years.

Note that administration of a dose of either Menveo formulation to a patient who is older than the FDA-licensed upper age limit of 55 years should not be reported to VAERS and is not considered an error. This is because ACIP recommendations state that Menveo may be administered to adults age 56 or older when MenACWY vaccination is indicated and MenQuadfi (MenACWY-TT, Sanofi, licensed with no upper age limit) is not available.

Last reviewed: March 24, 2024

CDC has included in the Vaccine Storage and Handling Toolkit an addendum that contains additional details concerning special considerations for COVID-19 and mpox vaccines. This is available at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf.

Last reviewed: July 26, 2023

Eculizumab (Soliris) and related long-acting compounds, such as ravulizumab (Ultomiris), inhibit the terminal complement pathway. People with persistent complement component deficiency due to an immune system disorder or use of a complement inhibitor are at increased risk for meningococcal disease even if fully vaccinated. This patient should be given a 2-dose primary series of MenACWY vaccine (2 doses separated by at least 8 weeks) and a 2- or 3-dose series (depending on brand) of MenB vaccine. The patient should receive regular booster doses of MenACWY and MenB as long as he remains at risk: a booster dose of MenACWY every 5 years and a booster dose of MenB one year after completion of the primary series, followed by a booster dose of MenB every 2–3 years thereafter.

Penbraya (MenABCWY, Pfizer) contains MenB-Fhbp (Trumenba) and is given as two doses, 6 months apart, when vaccination against all 5 serogroups is needed. For people age 10 years or older at increased risk of meningococcal disease, like this patient, Penbraya may be used for MenACWY and MenB (Trumenba) doses (including booster doses) if both vaccines would be given on the same clinic day and at least 6 months have elapsed since most recent Penbraya dose.

Because patients treated with complement inhibitors can develop invasive meningococcal disease despite vaccination, clinicians using these products also may consider antimicrobial prophylaxis for the duration of complement inhibitor therapy.

Last reviewed: March 24, 2024

As of 2024, there are two options for MenACWY vaccination. In 2020, MenQuadfi (Sanofi) was approved for use in all people ages 2 years and older. If MenQuadfi is not available and vaccination is needed, you may administer Menveo.

Last reviewed: March 24, 2024

Historically, AI/AN infants were more likely than other U.S.-born infants to develop Hib meningitis before being old enough to complete a primary series of Hib-containing vaccine. ACIP prefers that AI/AN infants be vaccinated with PedvaxHIB because it can stimulate protective levels of antibodies after the first dose.

Vaxelis contains the same Hib vaccine components as PedvaxHIB, but in smaller quantities. At the time ACIP approved Vaxelis, no data were available on the immune response to the Hib component of Vaxelis after the first dose, so ACIP did not make a preferential recommendation for Vaxelis in AI/AN infants. ACIP stated it would re-evaluate its decision if new information becomes available.

Last reviewed: July 15, 2023

Congratulations on your hard work! You would be surprised at the number of people who, just like you, do a careful job of recording temperatures, but then they fail to act on them when the temperatures go out of range. Always take immediate action when you notice an out-of-range temperature. You may need to move the vaccines temporarily to a more reliable storage unit and determine the source of the problem. It may be something quite fixable (e.g., excessive lint or dust on the coils), and you will be back in business after you determine that the temperature is back in range after a few hours.

Above all, don’t chart an out-of-range temperature and not act on it! Immunize.org has created temperature recording logs and a troubleshooting record to document unacceptable vaccine storage events. The CDC Storage and Handling Toolkit contains detailed guidance on the management of a temperature excursion. See pages 15–17 at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf. Refer to the addendum to the toolkit for specific guidance on COVID-19 and mpox vaccines.

Last reviewed: July 26, 2023

No. RSV vaccination during pregnancy is only recommended for pregnant people who are at the recommended stage of pregnancy (32 weeks through 36 weeks 6 days’ gestation) during the recommended time of year (typically September through January). In regions with seasonal patterns of RSV that differ from the continental United States, such as Alaska, Hawaii, or subtropical parts of Florida, follow local public health or health care guidance on timing, which may differ.

Last reviewed: January 22, 2024

PPSV23 is not effective in children less than 24 months of age. PPSV23 given to children younger than 2 years old should not be considered part of the pneumococcal vaccination series. PCV15 or PCV20 should be administered as soon as the error is discovered. Any time the wrong vaccine is given, the parent/patient should be notified. The facility staff should review their vaccination training and clinical procedures to prevent future vaccine administration errors.

Last reviewed: April 5, 2024

Yes. Adults with a history of herpes zoster should receive Shingrix. If a person is experiencing an episode of zoster, vaccination should be delayed until the acute phase of the illness is over and symptoms abate.

Last reviewed: March 9, 2022

The schedule for HepB vaccination depends on the brand in use. Heplisav-B is administered intramuscularly on a 2-dose schedule with doses separated by 1 month (4 weeks). Routine primary vaccination with PreHevbrio, Engerix-B, Recombivax HB, or Twinrix consists of three intramuscular doses administered on a 0-, 1-, and 6-month schedule.

Alternative vaccination schedules for Engerix-B and Recombivax HB (for example, 0, 1, and 4 months or 0, 2, and 4 months) have been demonstrated to elicit dose-specific and final rates of seroprotection similar to those obtained on a 0-, 1-, and 6-month schedule. Increasing the interval between the first 2 doses has little effect on immunogenicity or the final antibody concentration. The third dose confers the maximum level of seroprotection and provides long-term protection.

Recombivax HB may be administered in a 2-dose schedule at 0 and 4–6 months for adolescents age 11 through 15 years using the adult formulation (1.0 mL). Pediarix (GSK) and Vaxelis (MCM) combination vaccines are administered at age 2, 4, and 6 months; they are not used for the birth dose. Twinrix may be administered on an accelerated 4-dose schedule at 0, 7, and 21–30 days, followed by a dose at 12 months.

HepB vaccination of adult (age 20 years and older) hemodialysis patients consists of high-dose (40 µg) Recombivax HB administered on a 0-, 1-, and 6-month schedule or high-dose (2 mL) Engerix-B administered on a 0-, 1-, 2-, and 6-month schedule. Heplisav-B and PreHevbrio have not been studied in patients on hemodialysis.

Last reviewed: July 21, 2023

No. There is no federal requirement for signed consent for any dose of a vaccine licensed for use by the FDA. The federal requirement is to provide all adult patients or parents/legal representatives of minor children with the appropriate VIS for each dose of vaccine administered. Some clinics, agencies, and/or state immunization programs may have requirements for signatures. Contact information for your state health department is available at www.immunize.org/coordinators.

Last reviewed: June 6, 2023

In the 2013 revision of its MMR vaccine recommendations ACIP expanded the use of post-exposure IG prophylaxis for measles. Intramuscular IG (IGIM) should be administered to all infants younger than 12 months who have been exposed to measles. The dose of IGIM is 0.5 mL/kg of body weight; the maximum dose is 15 mL. Alternatively, MMR vaccine can be given instead of IGIM to infants age 6 through 11 months, if it can be given within 72 hours of exposure.

In addition to infants under the age of 12 months, immune globulin may be used as measles post-exposure prophylaxis for susceptible pregnant people or susceptible people who are severely immunocompromised. For details on the dosage and use of immune globulin, please refer to the measles control section in Chapter 7 of the CDC Manual for the Surveillance of Vaccine-Preventable Diseases:  www.cdc.gov/vaccines/pubs/surv-manual/chpt07-measles.html#control.

IG is not indicated for people who have received 1 dose of measles-containing vaccine at age 12 months or older unless they are severely immunocompromised. IG should not be used to control measles outbreaks. IG has not been shown to prevent mumps or rubella infection after exposure and is not recommended for that purpose.

Last reviewed: June 19, 2023

There is no ACIP recommendation for additional doses of 9vHPV for people who started the series with 2vHPV or 4vHPV and completed the series with 9vHPV.

Last reviewed: March 2, 2024

Novavax COVID-19 Vaccine, Adjuvanted contains the Omicron XBB.1.5 subvariant SARS-CoV-2 spike protein and Matrix-M adjuvant. The saponin-based adjuvant is made from extracts of the bark of the Soapbark tree native to Chile. It is added to enhance the immune response of the vaccine recipient. The spike protein is produced in insect cells.

It is authorized for emergency use in people age 12 years or older as a two-dose primary series for previously unvaccinated individuals (whether or not they are immunocompromised), with the doses given at least 3 to 8 weeks apart. Individuals who have had one or more doses of any previous authorized or approved COVID-19 vaccine formulation are recommended to receive only one dose of the current formulation. An additional dose of Novavax or any other COVID-19 vaccine is recommended for adults age 65 years or older at least 4 months after their first dose of the 2023-2024 Formula COVID-19 vaccine. Individuals with moderate or severe immunocompromise may receive additional doses as determined by their healthcare team, based on their specific circumstances.

Last reviewed: March 19, 2024

Recommendations to separate MenACWY and PCV only applied to MenACWY-D (Menactra, Sanofi), which is no longer available in the United States. You may administer PCV vaccines and MenQuadfi, Menveo, or Penbraya (if this MenABCWY is indicated) at the same time. A 10-year-old with persistent complement component deficiency also should be vaccinated against MenB with an appropriate vaccine.

As long as the child remains at high risk of meningococcal disease due to complement inhibitor use, booster doses of both MenACWY and MenB are recommended. A MenACWY booster dose should be given every 5 years and a MenB booster dose should be given one year after the completion of the primary series, followed by a booster dose every 2–3 years thereafter.

Because patients treated with complement inhibitors can develop invasive meningococcal disease despite vaccination, clinicians using Ultomiris or other complement inhibitors also may consider antimicrobial prophylaxis for the duration of complement inhibitor therapy.

Last reviewed: March 24, 2024

Infliximab is an IgG monoclonal antibody that neutralizes the biological activity of tumor necrosis factor-alpha. Like other IgG antibodies infliximab crosses the placenta. Infliximab has been detected in the blood of infants up to 6 months following birth. Consequently, these infants may be at increased risk of serious infection.

Neither ACIP nor CDC provides specific guidance on this issue because there are few data on safety or efficacy in children exposed to potentially immunosuppressive biologics during pregnancy. As noted above, practitioners should consider the potential risks and benefits of administering rotavirus vaccine to infants with known or suspected altered immunocompetence. Consultation with an immunologist or infectious diseases specialist is advised.

The manufacturer recommends that live vaccines (rotavirus and BCG) be deferred for at least six months after birth for infants whose mothers received infliximab during pregnancy. Hence, if a practitioner follows the manufacturer’s recommendation the child would not be eligible to receive rotavirus vaccine because according to ACIP guidelines the rotavirus vaccine series should not to be started after age 15 weeks 0 days.

Inactivated vaccines should be given on schedule.

Last reviewed: June 7, 2023

Hib meningitis incidence historically peaked at a younger age (4–6 months) among AI/AN infants than among other U.S. infant populations (6–7 months). Vaccination with a primary series of PedvaxHib (PRP-OMP, Merck) is preferred for AI/AN infants because this vaccine can produce a protective antibody response after the first dose.

At the current time, it is unknown whether Vaxelis (DTaP-IPV-Hib-HepB), which contains a smaller quantity of PRP-OMP than PedvaxHib, produces a similar protective antibody response after the first dose. Therefore, Vaxelis is not preferred for AI/AN infants at this time.

Last reviewed: July 31, 2022

ACIP recommends a 3-dose Dengvaxia vaccine schedule, with doses administered at 0, 6 months, and 12 months.

Last reviewed: February 16, 2022

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.

Last reviewed: December 28, 2022

Varicella vaccine is most effective in preventing chickenpox or reducing the severity of the disease if used within 72 hours (3 days), and may still be helpful up to 5 days after exposure. However, not every exposure to varicella leads to infection, so for future immunity, varicella vaccine should be given to a person age 12 months or older who does not have a contraindication to vaccination, even if more than 5 days have passed since an exposure.

Last reviewed: May 16, 2023

There are two different DTaP products currently used in the U.S. for the primary series for children ages 2 months through 6 years (Daptacel [Sanofi] and Infanrix [GSK]). ACIP has recommended that, whenever feasible, healthcare providers should use the same brand of DTaP vaccine for all doses in the vaccination series. If vaccination providers do not know or have available the type of DTaP vaccine previously administered to a child, any DTaP vaccine may be used to continue or complete the series. For vaccines in general, vaccination should not be deferred because the brand used for previous doses is not available or is unknown (see the ACIP’s General Best Practices Guidance for Immunization at www.cdc.gov/vaccines/hcp/acip-recs/general-recs/timing.html).

Last reviewed: March 31, 2022

Because more than one type or subtype of influenza virus can circulate in any given influenza season, providers should offer influenza vaccination to unvaccinated people throughout the influenza season, including people who may have had an influenza illness already in the season.

Last reviewed: September 10, 2023

Begin by asking a general question about whether the person has an allergy to any food, medication, or vaccine. If they report an allergy to gelatin or foods that contain gelatin, you could follow up by asking if they can eat Jell-O™ and gelatin-type products. Gelatin allergies are extremely rare. Only severe, life-threatening (anaphylactic) allergy is a contraindication to vaccination.

Last reviewed: August 29, 2022

In general, vaccination series should be completed with the same product. However, CDC guidance states that you may complete a hepatitis B vaccination series with any available, age-appropriate hepatitis B product if the brand of the previous dose is unknown or unavailable.

One hepatitis B vaccine (Heplisav-B, Dynavax) is recommended as a 2-dose series, with doses administered at least 4 weeks apart. All other hepatitis B vaccine product options for adults (Engerix-B, GSK; PreHevbrio, VBI; Recombivax HB, Merck; Twinrix [HepA-HepB], GSK) are routinely recommended on a 3-dose schedule: 0, 1-2 months, and 6 months; dose 2 may be given a minimum of 4 weeks after dose 1 and dose 3 may be given a minimum of 8 weeks after dose 2 and 16 weeks after dose 1. The table below does not address the accelerated, 4-dose Twinrix (combination HepA-HepB) schedule option (doses given on days 0, 7, 21, and 12 months), nor does it address completion of the hepatitis A component of Twinrix.

The table below displays the options and timing for hepatitis B vaccination with a mixed-product series. All mixed-product options require 3 doses because the only 2-dose option is two doses of Heplisav-B.

Timing of completion of a routine adult hepatitis B vaccination schedule with a single product or mixed product series:

Dose 1 Dose 2
(at least 4 weeks after dose 1)		 Dose 3
(at least 8 weeks after dose 2 and 16 weeks after dose 1)
Routine, single product schedule H* H —
E, P, R, or T* Same product as dose 1 Same product as dose 2
If different products are used E, P, R, or T E, P, R, or T E, P, R, or T
H E, P, R, or T E, P, R, or T
E, P, R, or T H E, P, R, or T
E, P, R, or T E, P, R, or T H
H E, P, R, or T H
E, P, R, or T H H**

* H = Heplisav-B; E = Engerix-B; P = PreHevbrio; R = Recombivax HB; T = Twinrix
** If two doses of H are used to complete a series started with E, P, R, or T, the final dose may be administered 4 weeks after dose 2 (for a complete H series)

Last reviewed: June 17, 2024

CDC currently has no plans to develop VISs for Pediarix, Twinrix, Kinrix, Quadracel, or Pentacel. When administering these combination vaccines, use the VISs for all component vaccines. For certain combination vaccines given to children, you can use the multi-vaccine VIS (which includes DTaP, Hib, HepB, polio, and PCV) and check the appropriate box(es), just as you would if you were administering the individual vaccines. If the multi-vaccine VIS is unavailable, you should use the individual vaccine VISs. A VIS was developed for MMRV (ProQuad, by Merck) because of its unique adverse reaction profile.

Last reviewed: June 6, 2023

No. You should not use it until you know more. If you find that a vaccine has been exposed to an inappropriate temperature, try to determine the reason for the temperature excursion, mark the vaccine “Do Not Use,” and contact the manufacturer or the state or local health department to determine if the vaccine may be used without concern that its effectiveness has been diminished.

Do not leave vaccines in a storage unit that does not maintain temperatures within the recommended range. If you are unable to stabilize the temperature in your unit within the required range, or temperatures in the unit are consistently at the extreme high or low end of the range, identify an alternative unit with appropriate temperatures and sufficient storage space until the primary unit can be repaired or replaced.

Last reviewed: July 26, 2023

Only the Menveo two-vial formulation requiring reconstitution (MenACWY-CRM) should be used for children age 2 through 23 months. MenQuadfi (MenACWY-TT) is approved for people age 24 months or older. The one-vial formulation of Menveo that does not require reconstitution is approved for children and adults age 10 through 55 years. Penbraya (MenABCWY), may be an option for people age 10 years or older when both MenACWY and MenB (Trumenba) vaccination is needed at the same visit. Unlike MenB vaccines, when more than one brand of MenACWY vaccine is age-appropriate, they are interchangeable.

Last reviewed: March 24, 2024

Yes. Studies from the United States, South Africa, and the United Kingdom have shown that people with HIV infection have a risk of invasive meningococcal disease that is 11–24 times higher than the general population. In the United States, this excess risk is specifically for serogroups C, W, and Y. ACIP recommends routine MenACWY vaccination of all HIV-infected people 2 months of age and older. Children younger than age 2 years should be vaccinated using a multidose schedule based upon age (see the Immunize.org document “Meningococcal ACWY Vaccine Recommendations by Age and Risk Factor,” available at www.immunize.org/catg.d/p2018.pdf for details).

People age 2 years and older with HIV infection who have not been previously vaccinated should receive a 2-dose primary series of MenACWY (doses separated by at least 8 weeks). People with HIV infection who have previously received one dose of MenACWY should receive a second dose at the earliest opportunity (at least 8 weeks after the previous dose) and then receive booster doses at the appropriate intervals. ACIP does not recommend routine meningococcal serogroup B vaccination of people with HIV infection: MenB may be given based upon shared clinical decision-making to people with HIV who are age 16 through 23 years old, preferably between ages 16 and 18 years.

Last reviewed: March 24, 2024

The Advisory Committee on Immunization Practices (ACIP) recommends routine HepA vaccination for the following groups:

  • All children at age 1 year (12–23 months)
  • All children and adolescents age 2 through 18 years who have not previously received HepA should be vaccinated (i.e., routine catch-up vaccination)
  • People living with HIV infection
  • Travelers age 12 months and older to areas of the world with intermediate or high hepatitis A virus (HAV) endemicity. Low endemicity regions include the United States, Canada, Western Europe, Japan, New Zealand, and Australia. For more information, see the CDC travel health website for current information about specific countries at https://wwwnc.cdc.gov/travel or the CDC Yellow Book. (wwwnc.cdc.gov/travel/yellowbook/2020/travel-related-infectious-diseases/hepatitis-a). When in doubt, vaccinate.
  • Infants age 6 through 11 months traveling outside the United States should receive 1 dose when protection against HAV infection is recommended. The travel dose does not count toward the routine HepA series which should be initiated at age 1 year with the appropriate dose and schedule. In these instances, the child will receive a total of 3 doses of HepA vaccine.
  • Men who have sex with men
  • Users of illegal drugs, injectable or noninjectable
  • People who are homeless or in unstable living arrangements, including shelters
  • Previously unvaccinated people who anticipate having close personal contact with an international adoptee from a country of high or intermediate endemicity during the first 60 days following the adoptee’s arrival in the U.S.
  • People who work with HAV-infected nonhuman primates or with HAV in a research laboratory setting
  • People with chronic liver disease (including but not limited to people with hepatitis B infection, hepatitis C infection, cirrhosis, fatty liver disease, alcoholic liver disease, autoimmune hepatitis, or an ALT or AST level persistently greater than twice the upper limit of normal)
  • People identified during pregnancy to be at risk for HAV infection due to presence of a specific risk factor for exposure or at risk for severe outcome from HAV infection (for example, those with chronic liver disease or with HIV infection).
  • During an outbreak, any unvaccinated person who is identified as at risk for HAV infection or at risk for severe disease from HAV
  • Any person who wishes to be immune to hepatitis A

HepA vaccination is not routinely recommended for healthcare personnel, food handlers, sewage workers, or day care providers because there is no evidence that their occupational risks of HAV exposure are significantly higher than the general population. However, any person who desires protection from HAV infection may be vaccinated.

For details about CDC recommendations for the prevention of hepatitis A, see the 2020 recommendations of the Advisory Committee on Immunization Practices (ACIP): www.cdc.gov/mmwr/volumes/69/rr/pdfs/rr6905a1-H.pdf.

Last reviewed: June 25, 2023

This page was updated on .

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