Ask the Experts: All Questions

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

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Results (1316)

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

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

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: September 10, 2023

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

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 RSV vaccines 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/vaccinesafety/ensuringsafety/monitoring/v-safe/index.html.

Last reviewed: March 19, 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: March 19, 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

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

You may find guidance on the storage and handling of each COVID-19 vaccine in the CDC’s Vaccine Storage and Handling Toolkit addendum on COVID-19 and mpox vaccines: www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf.

CDC has produced “At-A-Glance” summaries for each COVID-19 vaccine, including storage and handling conditions.

Immunize.org has assembled links to key COVID-19 vaccine storage and handling resources 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: March 19, 2024

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.

Details are provided in the CDC Vaccine Storage and Handling Toolkit addendum on COVID-19 and mpox vaccines: www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf.

There may be instances when the only option is to transport vaccine in a predrawn syringe. CDC refers to the U.S. Pharmacopeia (USP) guidance for transporting predrawn vaccine in syringes in the USP COVID-19 Vaccine Toolkit: Operational Considerations for Healthcare Practitioners. The complete document provides detailed guidance on COVID-19 vaccine transport and is available for download at no charge from this site: www.usp.org/covid-19/vaccine-handling-toolkit.

Last reviewed: March 19, 2024

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

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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