Ask the Experts: All Questions

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Results (1361)

IIV should be administered in the anterolateral thigh muscle of an infant or young child. IIV and RIV (approved for people age 18 years and older) should be administered in the deltoid muscle of an older child, adolescent, or adult. The anterolateral thigh muscle can also be used for an older child, adolescent, or adult if necessary. It is critical that intramuscular influenza vaccine be injected into a muscle. Influenza vaccination season is an opportune time to review proper intramuscular injection techniques with your staff. Immunize.org has prepared a printable document on how to administer intramuscular vaccine injections (available at www.immunize.org/catg.d/p2020.pdf) that can be used as a staff training tool.

Last reviewed: August 11, 2024

For immunocompetent HCP, periodic testing or periodic boosting is not needed. Postvaccination testing (anti-HBs) should be done 1–2 months after the last dose of the HepB series. If adequate anti-HBs (at least 10 mIU/mL) is present, nothing more needs to be done. This information should be made available to the employee and recorded in the employee’s health record.

Last reviewed: July 21, 2023

An infant who experiences an afebrile seizure following a dose of DTaP requires further evaluation. An infant with a recent seizure or an evolving neurologic condition should not receive further doses of DTaP or DT until the condition has been evaluated and stabilized. Other indicated vaccines may be administered on schedule. To assure that the child is at least protected against tetanus and diphtheria, the decision to give either DTaP or DT should be made no later than the first birthday.

Last reviewed: March 31, 2022

Vaccine safety monitoring in the United States indicated an increased risk of GBS within 42 days of vaccination with the Janssen COVID-19 Vaccine, with the highest risk among people ages 40 through 64. Most reports were in males. Janssen COVID-19 Vaccine is no longer available in the United States.

Any FDA-authorized or FDA-licensed COVID-19 vaccine may be given to individuals with a history of GBS.

Last reviewed: November 16, 2024

All children with risk factors for pneumococcal disease or its complications should be vaccinated on time with either PCV15 or PCV20. High-risk children who complete the pneumococcal vaccination schedule without a dose of PCV20 will require additional pneumococcal vaccination. The vaccination needed after completion of the routine series (with PCV13, PCV15, or PCV20) depends on the pneumococcal vaccine product available, the child’s age, specific type of risk factor, and past pneumococcal vaccination history.

There are four resources that can help you determine what pneumococcal vaccinations are recommended for a specific high-risk child:

Last reviewed: November 13, 2024

No. Immunocompetent people known to have responded to HepB vaccination in the past do not require additional passive or active immunization. Postvaccination testing should be done 1–2 months after the original vaccine series is completed. In this scenario, the initial postvaccination testing showed that the healthcare professional was protected. Substantial evidence suggests that adults who respond to a HepB series (anti-HBs of at least 10 mIU/mL) are protected from chronic HBV infection for at least 30 years, even if there is no detectable anti-HBs currently. Only immunocompromised people (for example, dialysis patients, some people living with HIV) need to have anti-HBs testing performed periodically. Booster doses of vaccine to maintain their protective anti-HBs concentrations to at least 10 mIU/mL are recommended for dialysis patients and may be given to some people living with HIV.

Table 3: Postexposure management of healthcare personnel after occupational percutaneous and mucosal exposure to blood and body fluids, by healthcare personnel HepB vaccination and response status

Healthcare personnel status Postexposure testing Postexposure prophylaxis Postvaccination
serologic
testing†
Source patient
(HBsAg)		 HCP testing
(anti-HBs)		 HBIG* Vaccination
Documented responder§ after
complete series		 No action needed
Documented nonresponder
after 2 complete series		 Positive/unknown Not indicated HBIG x2 separated
by 1 month		 — No
Negative No action needed
Response unknown after
complete series		 Positive/unknown <10mIU/mL** HBIG x1 Initiate
revaccination		 Yes
Negative <10mIU/mL None
Any result >10mIU/mL No action needed
Unvaccinated/incompletely
vaccinated or vaccine refusers		 Positive/unknown —** HBIG x1 Complete
vaccination		 Yes
Negative — None Complete
vaccination		 Yes

Abbreviations: HCP = health-care personnel; HBsAg = hepatitis B surface antigen; anti-HBs = antibody to hepatitis B surface antigen; HBIG = hepatitis B immune globulin.

* HBIG should be administered intramuscularly as soon as possible after exposure when indicated. The effectiveness of HBIG when administered >7 days after percutaneous, mucosal, or nonintact skin exposures is unknown. HBIG dosage is 0.06 mL/kg.

† Should be performed 1–2 months after the last dose of the HepB vaccine series (and 6 months after administration of HBIG to avoid detection of passively administered anti-HBs) using a quantitative method that allows detection of the protective concentration of anti-HBs (>10 mIU/mL).

§ A responder is defined as a person with anti-HBs >10 mIU/mL after 1 or more complete series of HepB vaccine.

¶ A nonresponder is defined as a person with anti-HBs <10 mIU/mL after 2 complete series of HepB vaccine.

** HCP who have anti-HBs <10mIU/mL, or who are unvaccinated or incompletely vaccinated, and sustain an exposure to a source patient who is HBsAg-positive or has unknown HBsAg status, should undergo baseline testing for HBV infection as soon as possible after exposure, and follow-up testing approximately 6 months later. Initial baseline tests consist of total anti-HBc; testing at approximately 6 months consists of HBsAg and total anti-HBc.

Source: This table from Prevention of Hepatitis B Virus Infection in the United States: Recommendations of the Advisory Committee on Immunization Practices. MMWR 2018;67(RR-1): 18 www.cdc.gov/mmwr/volumes/67/rr/pdfs/rr6701-H.pdf

Last reviewed: July 21, 2023

There is no evidence that any of the COVID-19 vaccines affect current or future fertility.

Last reviewed: November 16, 2024

Usually, an “allergy” to tetanus toxoid is anecdotal and not a true anaphylactic reaction to modern tetanus toxoid. Patients often claim to be allergic to tetanus toxoid because of (1) an exaggerated local reaction (which is not an allergy) or (2) a reaction to a tetanus vaccine received many years ago (probably serum sickness from equine tetanus antitoxin). A history of one of these events is not a contraindication to modern tetanus toxoid, Td, or Tdap.

Only an allergist-confirmed severe allergy (e.g., anaphylaxis) to tetanus toxoid should be accepted as a valid contraindication to a modern tetanus-toxoid containing product. A person who has an allergist-confirmed anaphylactic allergy to tetanus toxoid has no recourse for pertussis vaccination because no single-antigen pertussis vaccine is licensed for use in the United States.

Last reviewed: March 31, 2022

This is not an acceptable practice. Doses of influenza vaccine (or any other vaccine) should never be split into “half doses.” If a “half dose” is administered, it should not be accepted as a valid dose. The second half of the dose may be administered if the error is caught and corrected on the same day; if not, repeat the vaccination on a different day as soon as possible with a full age-appropriate dose.

Last reviewed: August 11, 2024

No. PPSV23 was never recommended to be given every 5 years. If you see a patient age 65 years or older who, as a result of this practice of repeating doses of PPSV23, has had multiple doses of PPSV23, evaluate their history of pneumococcal conjugate vaccination. If they have no or unknown history of any doses of PCV, administer a single dose of PCV15, PCV20, or PCV21 at least 1 year after their most recent dose of PPSV23. 

If they have also received a dose of PCV13 in the past, they may receive a dose of PCV20 or PCV21 at least 5 years after their most recent pneumococcal vaccination based on shared clinical decision-making.

Last reviewed: November 13, 2024


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Last reviewed: May 26, 2023

Tetanus toxoid has never contained horse serum or protein. Equine tetanus antitoxin (horse derived) was the only product available for the prevention of tetanus prior to the development of tetanus toxoid in the 1940s. Equine antitoxin was also used for passive post-exposure prophylaxis of tetanus (e.g., after a tetanus-prone wound) until the development of human tetanus immune globulin in the late 1950s. Equine tetanus antitoxin has not been available in the U.S. for at least 40 years.

Last reviewed: March 31, 2022

In general, no, but the type of testing (pre-exposure or post-exposure) depends on the healthcare worker’s profession and work setting. The risk for hepatitis B virus (HBV) infection for vaccinated healthcare personnel (HCP) can vary widely by setting and profession. The risk might be low enough in certain settings that assessment of hepatitis B surface antibody (anti-HBs) status and appropriate follow-up can be done at the time of exposure to potentially infectious blood or body fluids. This approach relies on HCP recognizing and reporting blood and body fluid exposures and might be applied on the basis of documented low risk, implementation, and cost considerations. Trainees, some occupations (such as those with frequent exposure to sharp instruments and blood), and HCP practicing in certain populations are at greater risk of exposure to blood or body fluid exposure from an HBsAg-positive patient. Vaccinated HCP in these settings/occupations would benefit from a pre-exposure approach.

Because CDC recommends, as of March 2023, that all adults receive a triple panel screening test for HBV once in their lifetime, it may be practical to conduct the routine triple panel test on any HCP who needs testing and has not had a triple panel screening test.

Last reviewed: July 21, 2023

Yes. The two available quadrivalent meningococcal conjugate vaccines, Menveo (MenACWY-CRM, GSK) and MenQuadfi (MenACWY-TT, Sanofi), may be administered at the same time as PCV13 or at any interval before or after receipt of PCV13.

Last reviewed: November 13, 2024

Yes. Syncope may occur following any vaccination. It is prudent for all people to be observed for syncope for at least 15 minutes after any vaccination. Immunize.org has a 1-page resource for healthcare professionals that summarizes ways to reduce the risk of post-vaccination syncope: www.immunize.org/wp-content/uploads/catg.d/p4260.pdf.

Last reviewed: August 11, 2024

ACIP recommends that healthcare personnel with written documentation of having received a properly spaced series of HepB in the past (such as in infancy or adolescence) but who now test negative for anti-HBs should receive a single “booster” or “challenge” dose of HepB and be retested 1–2 months later. Those who test positive following the “booster” dose are immune and require no further vaccination or testing. Those who test negative should complete a second 2- or 3-dose series of HepB on the usual schedule and be tested again 1–2 months after the last dose. The “booster” dose counts as the first dose in this series. Heplisav-B or PreHevbrio may be used to revaccinate new healthcare personnel (including the challenge dose) initially vaccinated with a vaccine from a different manufacturer in the distant past who have anti-HBs less than 10 mIU/mL upon hire or matriculation. For more information see www.cdc.gov/mmwr/volumes/67/rr/pdfs/rr6701-H.PDF, pages 21–22.

Last reviewed: July 21, 2023

Certain vaccine syringes have small hubs where a volume of the vaccine that is withdrawn from the vial collects and is not available to be injected. Syringes without a hub are available; their use results in less vaccine wastage.

Last reviewed: August 11, 2024

ACIP recommends a single dose of tetanus immune globulin (TIG) for treatment of persons with tetanus. Although the optimal therapeutic dose has not been established, experts recommend 500 international units (IU), which appears to be as effective as higher doses ranging from 3,000 to 6,000 IU and causes less discomfort. Available preparations must be administered intramuscularly; TIG preparations available in the United States are not licensed or formulated for intrathecal or intravenous use. Infiltration of part of the dose locally around the wound is usually recommended if feasible, although the efficacy of this approach has not been proven. If TIG is not available, intravenous immune globulin (IGIV) can be used at a dose of 200 to 400 milligrams per kilogram (mg/kg). However, the Food and Drug Administration (FDA) has not approved IGIV for this use. In addition, anti-tetanus antibody content varies from lot to lot. See www.cdc.gov/tetanus/hcp/clinical-overview/index.html for more information on this issue.

Last reviewed: March 31, 2022

No, but the PPSV23 will render the PCV15 dose less immunogenic. In this scenario, the best schedule is to give a MenACWY vaccination (any brand) simultaneously with either PCV15 or PCV20. If PCV20 is given, no additional pneumococcal vaccine doses are recommended. If PCV15 is given, then PPSV23 should be given at least eight weeks later. ACIP recommends giving PCV before PPSV23 in order to maximize the immune response to PCV. PPSV23 may blunt the immune response to the serotypes contained in PCV if PCV is given after PPSV23, although in children there is a smaller effect than in adults. PCV21 (Capvaxive, Merck) is not an option because it is not licensed or recommended for use in children. Note that a 10-year-old child with persistent complement component deficiency should also be vaccinated against meningococcal B disease.

Last reviewed: November 13, 2024

There is a rare risk of myocarditis (inflammation of the heart muscle) and/or pericarditis (inflammation of the tissue surrounding the heart) following receipt of any COVID-19 vaccine. This rare risk is greatest in biological males age 12 through 39 years. Despite this risk, evaluation demonstrates that the benefits of vaccination clearly outweigh the risks in all age groups.

This risk appears related to age, biological sex, and the short (3- to 4-week) interval between primary series doses, where applicable. For individuals who are recommended to receive a primary series of more than one dose, extending the interval between doses to 8 weeks may reduce the rare risk of myocarditis following the second dose.

Most patients diagnosed with myocarditis after mRNA COVID-19 vaccination have been hospitalized for short periods, with most completely recovering from their acute symptoms. Post-vaccination myocarditis is milder than myocarditis following viral infection. CDC continues to assess long-term outcomes in people with myocarditis after mRNA COVID-19 vaccination.

People receiving COVID-19 vaccines, especially males age 12 through 39, should be counseled about the risk of myocarditis or pericarditis and advised to seek medical attention promptly if they develop chest pain, shortness of breath, or feelings of a fast, fluttering, or pounding heartbeat.

Cases of myocarditis and pericarditis were identified in clinical trials of Novavax COVID-19 Vaccine and have also been reported during post-authorization use outside the United States. These findings suggest that an increased risk for these conditions may be present after receiving Novavax COVID-19 vaccine.

Current recommendations are for a single dose of any FDA-licensed or FDA-authorized 2024–2025 Formula COVID-19 vaccine for most people age 5 years and older, even if the individual is previously unvaccinated. Previously unvaccinated individuals who receive Novavax vaccine are recommended to receive two doses, given 3 to 8 weeks apart.

CDC’s complete interim clinical considerations for COVID-19 vaccination and myocarditis or pericarditis are available here: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#myocarditis-pericarditis.

CDC also has published additional clinical considerations for the evaluation and care of patients with myocarditis or pericarditis following mRNA vaccination: www.cdc.gov/vaccines/covid-19/clinical-considerations/myocarditis.html.

Last reviewed: November 16, 2024

Anti-HBs testing for HCP who receive both hepatitis B immune globulin (HBIG) and hepatitis B vaccine can be conducted as soon as 6 months after receipt of the HBIG.

Last reviewed: July 21, 2023

Children age 7–10 years should receive Tdap if they are not fully vaccinated for prevention of pertussis. Otherwise they may receive Td or Tdap. If additional doses are necessary for full tetanus protection, they may be administered as Td or Tdap. Adolescents, and adults age 11 years and older should receive a single dose of Tdap, if they have not received a dose of Tdap after the 11th birthday, otherwise they may receive Td or Tdap. If additional doses are necessary for full tetanus protection, they may be administered as Td or Tdap.

Last reviewed: March 31, 2022

Yes. Pneumococcal vaccines are all inactivated vaccines, which means you can give all other recommended vaccines at the same visit (using separate syringes) or at any later time with no waiting period following the vaccination. All currently available meningococcal vaccines in the United States may be administered without regard to the timing of pneumococcal vaccination.

Last reviewed: November 13, 2024

No. Only the number of doses indicated in the manufacturer’s package insert should be withdrawn from the vial. For a 5.0 mL vial of Fluzone this is 10 doses. For Afluria  5.0 mL multidose vial, the package insert states that the stopper can be punctured up to 20 times, allowing up to 20 doses of 0.25 mL dose for children age 6–35 months old. After the maximum number of doses has been withdrawn or number of punctures of the stopper has met the FDA-recommended limit, the vial should be discarded, even if there is vaccine remaining in the vial and the expiration date has not been reached.

Last reviewed: August 11, 2024

Serious allergic reactions, such as anaphylaxis, in the minutes following vaccination are rare but are possible with any vaccine. Every vaccination site should have staff available who are trained and equipped to recognize and respond to signs of anaphylaxis in a vaccine recipient. See this CDC website for additional information about preparing for the management of anaphylaxis following COVID-19 vaccination: www.cdc.gov/vaccines/covid-19/clinical-considerations/managing-anaphylaxis.html?anaphylaxis-management.html.

Anaphylaxis following vaccination with mRNA COVID-19 vaccines is reported at a rate of approximately 5 cases per million doses administered.

An immediate severe allergic reaction to any component or previous dose of any mRNA COVID-19 vaccine is a contraindication to vaccination with both the Pfizer-BioNTech and Moderna vaccines (all formulations); however, such a reaction is generally a precaution to the use of the Novavax vaccine; see the CDC’s COVID-19 interim clinical considerations section on contraindications and precautions for details: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#contraindications.

CDC also provides specific COVID-19 vaccination guidance for people with a history of allergies or allergic reactions: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#history-allergies-reactions.

Last reviewed: November 16, 2024

No. HCP with written documentation of receipt of a complete, properly spaced HepB series AND a positive anti-HBs can be considered immune to HBV and require no further testing or vaccination. Testing unvaccinated or incompletely vaccinated HCP (including those without written documentation of vaccination) is not necessary and is potentially misleading because anti-HBs of 10 mIU/mL or higher as a correlate of vaccine-induced protection has only been determined for persons who have completed a HepB vaccination series. Persons who cannot provide written documentation of a complete HepB vaccination series should complete the series, then be tested for anti-HBs 1 to 2 months after the final dose.

Last reviewed: July 21, 2023

ACIP has not addressed this issue specifically. Puncture wounds, however, should be attended to as soon as possible. The decision to delay a booster dose of tetanus toxoid-containing vaccine following an injury should be based on the nature of the injury and likelihood that the injured person is susceptible to tetanus. The more likely the person is to be susceptible, the more quickly that tetanus prophylaxis should be administered. A person with a tetanus-prone wound (e.g., punctures, wounds contaminated with soil or fecal material) and who has no history of tetanus immunization must be vaccinated and given tetanus immune globulin (TIG) as soon as possible. A person with a documented series of at least three tetanus toxoid-containing products, with a booster dose within the previous 10 years ago is less likely to be susceptible to tetanus, and the need for a booster dose is not as urgent, particularly if the wound can be thoroughly cleaned. The more likely a person is to be completely susceptible to tetanus (i.e., unvaccinated or incompletely vaccinated), the sooner that TIG and Td/Tdap should be administered, even if it means a trip to the emergency department.

Last reviewed: March 31, 2022

No. The available data have been interpreted that any changes in antibody response to either vaccine’s components were clinically insignificant. If PCV20 and influenza vaccine are both indicated and recommended, they may be administered at the same visit.

Last reviewed: November 13, 2024

The dose does not need to be repeated. However, this is a vaccine administration error. Clinicians should carefully select an influenza vaccine and vaccine dose that is licensed for the age group of the person being vaccinated. The error should be conveyed to the child’s parent or guardian and reported to Vaccine Adverse Events Reporting System (VAERS) at www.vaers.hhs.gov. Actions should be taken to limit vaccine administration errors at the clinic where the error occurred. Immunize.org’s educational piece “Influenza Vaccine Products for the 2024-2025 Influenza Season” (available at www.immunize.org/catg.d/p4072.pdf) provides helpful information on the wide variety of influenza vaccines in use this season.

Last reviewed: August 11, 2024

In accordance with general best practices for vaccination, all people should be observed for at least 15 minutes after vaccination for signs of an immediate allergic reaction.

If you vaccinate a person who has a precaution to COVID-19 vaccination, you should consider a 30-minute observation period following vaccination. See CDC’s detailed considerations for people with a history of allergies or allergic reactions: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#history-allergies-reactions.

Last reviewed: November 16, 2024

No. HCP who have documentation of receiving a complete HepB series and who tested positive for anti-HBs (defined as anti-HBs of 10 mIU/mL or higher) are considered to be immune to hepatitis B. Immunocompetent persons have long-term protection against HBV and do not need further testing or vaccine doses. Some immunodeficient persons (including those on hemodialysis) may need periodic booster doses of hepatitis B vaccine.

Last reviewed: July 21, 2023

One dose of tetanus toxoid-containing vaccine (Tdap or Td) provides little or no protection. That is why tetanus immune globulin (TIG) is also recommended in this situation. See the Tetanus Prophylaxis for Wound Management section of the current ACIP statement, available at www.cdc.gov/mmwr/volumes/67/rr/pdfs/rr6702a1-H.pdf, pages 27–28. As far as timing, the toxoid and TIG should be given as soon as possible.

Last reviewed: March 31, 2022

No. There are no data on the effectiveness of pneumococcal conjugate vaccine given by the intravenous route. The patient has renal disease, so it is important to ensure that the dose they receive is effective. CDC recommends repeating the dose using the correct route of administration (intramuscular).

Last reviewed: November 13, 2024

RIV is not licensed for people younger than 18 years of age, so there are no data regarding safety and efficacy in this age group. However, no serious side effects would be expected. The dose does not need to be repeated and should be considered valid. Even if no adverse reaction occurs, vaccine administration errors like this should be reported to the Vaccine Adverse Events Reporting System (VAERS) at www.vaers.hhs.gov.

Last reviewed: August 11, 2024

Pneumococcal vaccination recommendations are complex, especially as newer conjugate vaccines are licensed and added to recommended options. Assessing what is needed for an individual patient of any age requires their age, pneumococcal vaccination history, and knowledge of any relevant high-risk conditions. There are several resources available from CDC and Immunize.org that can help:

CDC Resources:

  • PneumoRecs VaxAdvisor  Mobile App for Vaccine Providers (webpage): The app for your mobile device allows you to answer basic questions about the age, health conditions, and pneumococcal vaccination history for an individual patient. It then provides CDC’s recommended options for pneumococcal vaccination today. See more information and download the app at  www.cdc.gov/pneumococcal/hcp/vaccine-recommendations/app.html.  

Immunize.org Resources:

Last reviewed: November 13, 2024

CDC maintains a website for information for the public about COVID-19 vaccine safety: www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/allergic-reaction.html. 

For information about how to evaluate and manage people with a history of allergy who present for COVID-19 vaccination, see CDC’s additional considerations for people with a history of allergies or allergic reactions: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#history-allergies-reactions.

Last reviewed: November 16, 2024

No. The series should not be restarted. Continue the series from where you left off.

Last reviewed: July 21, 2023

The following guidance is taken directly from the CDC: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#adverse-events.

For licensed COVID-19 vaccines (Moderna and Pfizer-BioNTech in people ages 12 years and older), healthcare providers are strongly encouraged to report to VAERS:

  • Any adverse event that occurs after the administration of a vaccine licensed in the United States, whether or not it is clear that a vaccine caused the adverse event
  • Vaccine administration errors, whether or not associated with an adverse event

For COVID-19 vaccines given under an EUA, vaccination providers are required to report to VAERS:

  • Vaccine administration errors, whether or not associated with an adverse event
  • Serious adverse events regardless of causality. Serious adverse events per FDA are defined as:
    • Death
    • A life-threatening adverse event
    • Inpatient hospitalization or prolongation of existing hospitalization
    • A persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions
    • A congenital anomaly/birth defect
    • An important medical event that based on appropriate medical judgement may jeopardize the individual and may require medical or surgical intervention to prevent one of the outcomes listed above
  • Cases of Multisystem Inflammatory Syndrome (MIS) in children and adults
  • Cases of myocarditis
  • Cases of pericarditis
  • Cases of COVID-19 that result in hospitalization or death

Reporting is also encouraged for any other clinically significant adverse event, even if it is uncertain whether the vaccine caused the event. Information on how to submit a report to VAERS is available at https://vaers.hhs.gov or by calling 1-800-822-7967.

Last reviewed: November 16, 2024

PPSV23 may be administered by intramuscular (IM) or subcutaneous (Subcut) routes. Pneumococcal conjugate vaccines are administered IM. Immunize.org has produced a simple handout that summarizes the dose, route, site, and needle length for administration of all recommended vaccines to adults and children: www.immunize.org/catg.d/p3085.pdf.

Last reviewed: November 13, 2024

TIG is recommended for any wound other than a clean minor wound if the person’s vaccination history is either unknown, or the person has not had a full series of 3 doses of tetanus-containing vaccine. People with HIV infection or severe immunodeficiency who have contaminated wounds (including minor wounds) should also receive TIG, regardless of their history of tetanus immunizations. TIG should be given as soon as possible after the injury. The dose is 250 IU administered intramuscularly. See CDC’s web page for details: www.cdc.gov/tetanus/hcp/clinical-guidance/index.html.

Last reviewed: March 31, 2022

Because there is no documentation of vaccination, a vaccination series should be administered and postvaccination testing should be performed 1–2 months after the final dose of vaccine. There is no harm in receiving extra doses of vaccine. Postvaccination anti-HBs testing results should also be documented, including the date testing was performed. All healthcare settings should develop policies or guidelines to assure valid hepatitis B immunization.

Last reviewed: July 21, 2023

The incubation period of tetanus ranges from 3 to 21 days, averaging about 10 days. In general, the further the injury site is from the central nervous system, the longer the incubation period. In the opinion of the tetanus experts at the CDC, for a person who has been vaccinated but is not up to date, there is probably little benefit in giving TIG more than a week or so after the injury. For a person believed to be completely unvaccinated, it is suggested to increase this interval to 3 weeks (i.e., up to day 21 post injury). Td or Tdap should be given concurrently with TIG.

Last reviewed: March 31, 2022

All pneumococcal vaccines should be refrigerated at temperatures between 2°C (36°F) and 8°C (46°F). Do not freeze these vaccines. Vaccine exposed to freezing temperature should not be administered. For details of vaccine storage and handling, see the CDC Vaccine Storage and Handling Toolkit: www.cdc.gov/vaccines/hcp/downloads/storage-handling-toolkit.pdf.

Last reviewed: November 13, 2024

If the error is discovered on the same clinic day you can administer the other “half” of the FluLaval dose on the same day. If the error cannot be corrected on the same day, the partial dose should not be counted. The child should be recalled to the office as soon as possible and given a full age-appropriate repeat dose, either a 0.5 mL dose of FluLaval , a 0.5 mL dose of Fluarix , a 0.25 or 0.5 mL dose of Fluzone , a 0.25 mL dose of Afluria , or a 0.5 mL dose of Flucelvax.

Last reviewed: August 11, 2024

Multiple national surveillance systems are used to monitor the safety of COVID-19 vaccines in different ways. CDC provides information about vaccine safety surveillance systems, with links to information about the safety of each licensed and recommended vaccine, including COVID-19 vaccines, here: www.cdc.gov/vaccine-safety/index.html.

Last reviewed: November 16, 2024

No. A positive anti-HBs indicates that the vaccinated person is immune at the time the person was tested but does not assure that the person has long-term immunity. Long-term immunity has been demonstrated only for people attaining an adequate anti-HBs result of at least 10 mIU/mL after completing a full vaccination series. The most direct way to deal with this is to vaccinate the employee with a series of hepatitis B vaccine; test for anti-HBs in 1–2 months and document the result in the employee’s health record. An adequate anti-HBs result from a documented vaccine series would assure not only seroprotection, but long-term protection.

Last reviewed: July 21, 2023

All influenza vaccines (inactivated, recombinant, and live attenuated vaccines) should be stored at refrigerator temperature of 2° through 8°C (36° through 46°F). No influenza vaccine should be frozen. Influenza vaccine exposed to freezing temperature should not be used.

Last reviewed: August 11, 2024

Each of these products must be stored at 2° to 8°C (36° to 46°F). They should not be frozen or exposed to freezing temperatures.

Last reviewed: March 31, 2022

V-safe is a safety monitoring system that vaccine recipients can use to share with CDC how they feel after vaccination. It was created initially for COVID-19 vaccines. Currently, recipients of protein-based RSV vaccines (Arexvy, GSK; Abrysvo, Pfizer) also may register for V-safe. To learn more about the program and how to guide vaccine recipients who wish to participate, visit CDC’s website: www.cdc.gov/vaccine-safety-systems/v-safe/index.html.

Last reviewed: November 16, 2024

No. The COVID-19 vaccines are not currently part of the VICP, although a transition to the VICP is anticipated in the future. The COVID-19 vaccines are currently part of a similar program called the Countermeasures Injury Compensation Program (CICP). For more information, visit this web page: www.hrsa.gov/cicp.

Last reviewed: November 16, 2024

Do nothing. Data show that vaccine-induced anti-HBs levels might decline over time; however, immune memory (anamnestic anti-HBs response) remains intact following immunization. People with anti-HBs concentrations that decline to less than 10 mIU/mL are still protected against HBV infection. For healthcare professionals with normal immune status who have demonstrated adequate anti-HBs (at least 10 mIU/ mL) following full vaccination, booster doses of vaccine or periodic anti-HBs testing are not recommended.

Last reviewed: July 21, 2023


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Last reviewed: December 7, 2023

For details, refer to the specific vaccine’s package insert or Emergency Use Authorization Fact Sheet for Healthcare Providers.

Immunize.org has assembled links to key COVID-19 vaccine storage and handling resources, including fact sheets and package inserts, in the Checklist of Current Versions of U.S. COVID-19 Vaccination Guidance and Clinic Support Tools: www.immunize.org/catg.d/p3130.pdf.

Last reviewed: November 16, 2024

No. There are no regulations that require removal from job situations where exposure to bloodborne pathogens could occur; this is an individual policy decision within the organization. OSHA regulations require that employees in jobs where there is a reasonable risk of exposure to blood be offered HepB vaccine. In addition, the regulation states that adequate personal protective equipment be provided and that standard precautions be followed. Check your state OSHA regulations regarding additional requirements. If there are no state OSHA regulations, federal OSHA regulations should be followed. Adequate documentation should be placed in the employee record regarding non-response to vaccination. HCP who do not respond to vaccination should be tested for HBsAg and total anti-HBc to determine if they have chronic HBV infection. If the HBsAg and total anti-HBc tests are positive, HCP should receive appropriate counseling for preventing transmission to others as well as referral for ongoing care to a specialist experienced in the medical management of chronic HBV infection. People who are HBsAg-positive and who perform exposure-prone procedures should seek counsel from a review panel comprised of experts with a balanced perspective (for example, infectious disease specialists and their personal physician[s]) regarding the procedures that they can perform safely. They should not be excluded from work. People who test negative for HBsAg should be considered susceptible to HBV infection and should be counseled about precautions to prevent HBV infection and the need to obtain HBIG prophylaxis for any known or likely exposure to HBsAg-positive blood (see Table).

Last reviewed: July 21, 2023

Yes. HCP should not be discriminated against because of their hepatitis B status. All HCP should practice standard precautions, which are designed to prevent HBV transmission, both from patients to HCP and from HCP to patient. There is, however, one caveat concerning HBV-infected HCP. Those who have HBV levels 1000 IU/mL or 5000 genomic equivalents/mL or higher should not perform exposure-prone procedures (for example, gynecologic, cardiothoracic surgery) unless they have sought counsel from an expert review panel and been advised under what circumstances, if any, they may continue to perform these procedures. For more information on this issue, see “Updated CDC Recommendations for the Management of Hepatitis B Virus–Infected Health-Care Providers and Students,” MMWR, 2012; 61(RR03):1–12. This document is available at www.cdc.gov/mmwr/pdf/rr/rr6103.pdf.

Last reviewed: July 21, 2023

Although routine transportation of vaccines to different facilities is not generally recommended, there are times when this is necessary. CDC recommends transporting COVID-19 vaccine in unopened vials or manufacturer-filled syringes (MFS) and always with a continuous temperature monitoring device to ensure adherence to authorized storage times and temperatures. See the product package insert or EUA Fact Sheet for Healthcare Providers for details on permissible conditions for transport.

Last reviewed: November 16, 2024

Yes. HepB vaccines have been demonstrated to be safe when administered to infants, children, adolescents, and adults. Since 1982, well over 100 million people, including infants, children, and adults living in the United States have received at least one dose of HepB vaccine; more than a billion doses of HepB vaccine have been given worldwide. Vaccination causes a sore arm occasionally, but serious reactions are very rare.

Last reviewed: July 21, 2023

Many years of experience with Engerix-B and Recombivax HB vaccines indicate no apparent risk for adverse events to a developing fetus. Current vaccines contain noninfectious HBsAg and pose no risk to the fetus. If the mother is being vaccinated because of a risk factor for HBV infection (for example, a healthcare worker, a person with a sexually transmitted disease, an injection drug user, a person with multiple sex partners), vaccination should be initiated as soon as the risk factor is identified during the pregnancy. HBV infection during pregnancy might result in severe disease for the mother and chronic infection for the newborn.

There are no clinical studies of Heplisav-B or PreHevbrio during pregnancy. Available human data on these products administered during pregnancy are insufficient to assess vaccine-associated risks in pregnancy. Until safety data are available for Heplisav-B or PreHevbrio, providers should continue to use Engerix-B, Recombivax HB, or Twinrix for individuals needing hepatitis B vaccination during pregnancy.

Last reviewed: July 21, 2023

No. Administration of HepB soon after birth has not been associated with an increased rate of elevated temperatures or subsequent evaluations for possible sepsis in the first 21 days of life.

Last reviewed: July 21, 2023

A serious allergic reaction to a prior dose of HepB or a vaccine component is a contraindication to further doses of HepB. Engerix-B, Recombivax HB, Twinrix, and Heplisav-B are synthesized in yeast cells into which a plasmid containing the gene for HBsAg has been inserted. People with a severe allergic reaction to yeast should not be vaccinated with vaccines produced in yeast cells. PreHevbrio is produced in mammalian cells and may be used (in the absence of other contraindications) in an adult with a severe allergic reaction to yeast.

As with other vaccines, vaccination of people with moderate or severe acute illness, with or without fever, should be deferred until the illness improves. Vaccination is not contraindicated in people with a history of multiple sclerosis, Guillain-Barré syndrome, or autoimmune diseases such as systemic lupus erythematosus or rheumatoid arthritis.

Last reviewed: July 21, 2023

All hepatitis B-containing vaccines should be stored at refrigerator temperature at 2°C to 8°C (36°F to 46°F). The vaccines must not be frozen. Any vaccine exposed to freezing temperature should not be used. Do not use these or any other vaccines after the expiration date shown on the packaging. Any vaccine administered after its expiration date should be repeated.

Last reviewed: July 21, 2023

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