What Is the Hepatitis B Vaccine and Who Needs It?

What is hepatitis B, and why does the vaccine matter?

Hepatitis B is caused by the hepatitis B virus (HBV), which infects the liver. In some people the infection clears on its own within a few months (acute hepatitis B). In others — especially those infected as infants or young children — it becomes a lifelong chronic infection 1Ref 1Wodi AP, Issa AN, Moser CA, Cineas S (2025).Advisory Committee on Immunization Practices Recommended Immunization Schedule for Adults Aged 19 Years or Older — United States, 2025.Hepatitis B vaccination recommended for all adults through age 59 regardless of risk factors; risk-based groups for adults ≥60; birth dose recommendation. Chronic hepatitis B can damage the liver slowly over many years, eventually causing cirrhosis (scarring) or liver cancer.

Hepatitis B spreads through blood and body fluids — including during birth, through sexual contact, and through sharing equipment that contacts blood. It is not spread through casual contact like hugging, coughing, or sharing food.

How does the hepatitis B vaccine work?

The hepatitis B vaccine contains a protein from the surface of the virus — not live virus. This protein teaches the immune system to recognize and fight HBV without exposure to the actual infection.

The vaccine is given as a two- or three-dose series, depending on the formulation, spaced over several months 2Ref 2Weng MK, Doshani M, Khan MA, et al. (2022).Universal Hepatitis B Vaccination in Adults Aged 19–59 Years: Updated Recommendations of the Advisory Committee on Immunization Practices — United States, 2022.Universal hep B vaccination for adults 19–59 regardless of risk; Heplisav-B two-dose option at 0 and 1 month; Heplisav-B not recommended in pregnancy or hemodialysis; anti-HBs test for immunity check. A two-dose formulation (Heplisav-B) approved by the FDA in 2017 and recommended by ACIP in 2018 is available for adults 18 and older; it is given at 0 and 1 month and does not require a third dose 2Ref 2Weng MK, Doshani M, Khan MA, et al. (2022).Universal Hepatitis B Vaccination in Adults Aged 19–59 Years: Updated Recommendations of the Advisory Committee on Immunization Practices — United States, 2022.Universal hep B vaccination for adults 19–59 regardless of risk; Heplisav-B two-dose option at 0 and 1 month; Heplisav-B not recommended in pregnancy or hemodialysis; anti-HBs test for immunity check. After completing the series, protective antibody levels develop in the vast majority of people, and protection appears to be long-lasting. Routine boosters are not recommended for healthy individuals who completed the series.

Who should get the hepatitis B vaccine — children?

The first dose is recommended at birth, ideally within 24 hours of delivery 3Ref 3Issa AN, Wodi AP, Moser CA, Cineas S (2025).Advisory Committee on Immunization Practices Recommended Immunization Schedule for Children and Adolescents Aged 18 Years or Younger — United States, 2025.Hepatitis B birth dose recommendation within 24 hours of delivery; infant series schedule. A newborn can be infected during delivery if the mother carries the hepatitis B virus — and newborns are far more likely than adults to develop chronic infection. The two- or three-dose series is completed during the first six months of life as part of the routine childhood schedule. Universal infant hepatitis B vaccination became routine in the United States in the early 1990s.

Who should get the hepatitis B vaccine — adults?

In 2022, ACIP updated its guidance to recommend hepatitis B vaccination for all adults aged 19 through 59 who were not previously vaccinated — regardless of risk factors 2Ref 2Weng MK, Doshani M, Khan MA, et al. (2022).Universal Hepatitis B Vaccination in Adults Aged 19–59 Years: Updated Recommendations of the Advisory Committee on Immunization Practices — United States, 2022.Universal hep B vaccination for adults 19–59 regardless of risk; Heplisav-B two-dose option at 0 and 1 month; Heplisav-B not recommended in pregnancy or hemodialysis; anti-HBs test for immunity check. This universal approach eliminates the need for clinicians to identify and ask about stigmatizing behaviors and makes catch-up vaccination straightforward. Adults 60 and older may also be vaccinated based on their preferences and any risk factors 1Ref 1Wodi AP, Issa AN, Moser CA, Cineas S (2025).Advisory Committee on Immunization Practices Recommended Immunization Schedule for Adults Aged 19 Years or Older — United States, 2025.Hepatitis B vaccination recommended for all adults through age 59 regardless of risk factors; risk-based groups for adults ≥60; birth dose recommendation2Ref 2Weng MK, Doshani M, Khan MA, et al. (2022).Universal Hepatitis B Vaccination in Adults Aged 19–59 Years: Updated Recommendations of the Advisory Committee on Immunization Practices — United States, 2022.Universal hep B vaccination for adults 19–59 regardless of risk; Heplisav-B two-dose option at 0 and 1 month; Heplisav-B not recommended in pregnancy or hemodialysis; anti-HBs test for immunity check.

Adults born before routine infant vaccination was introduced in the early 1990s are the group most likely to have missed the series.

Which adults have especially strong reasons to be vaccinated?

Certain groups face a higher likelihood of exposure and should prioritize vaccination if not already immune 1Ref 1Wodi AP, Issa AN, Moser CA, Cineas S (2025).Advisory Committee on Immunization Practices Recommended Immunization Schedule for Adults Aged 19 Years or Older — United States, 2025.Hepatitis B vaccination recommended for all adults through age 59 regardless of risk factors; risk-based groups for adults ≥60; birth dose recommendation2Ref 2Weng MK, Doshani M, Khan MA, et al. (2022).Universal Hepatitis B Vaccination in Adults Aged 19–59 Years: Updated Recommendations of the Advisory Committee on Immunization Practices — United States, 2022.Universal hep B vaccination for adults 19–59 regardless of risk; Heplisav-B two-dose option at 0 and 1 month; Heplisav-B not recommended in pregnancy or hemodialysis; anti-HBs test for immunity check:

• People with multiple sexual partners
• People who inject drugs
• People living with someone who has hepatitis B
• Healthcare workers and first responders
• People who travel to regions with high hepatitis B prevalence
• People with chronic liver disease or HIV
• People who receive hemodialysis

People with existing liver conditions — including fatty liver disease or hepatitis C — have a strong reason to be protected against hepatitis B, as co-infection can accelerate liver damage.

What if you are not sure whether you were vaccinated?

Two reasonable options exist:

1. Check your records — state immunization registry, old vaccination cards, or a childhood provider. 2. Start the series or check immunity — re-vaccination is safe and does not cause harm. Alternatively, a hepatitis B surface antibody (anti-HBs) blood test can confirm whether you already have protective immunity 2Ref 2Weng MK, Doshani M, Khan MA, et al. (2022).Universal Hepatitis B Vaccination in Adults Aged 19–59 Years: Updated Recommendations of the Advisory Committee on Immunization Practices — United States, 2022.Universal hep B vaccination for adults 19–59 regardless of risk; Heplisav-B two-dose option at 0 and 1 month; Heplisav-B not recommended in pregnancy or hemodialysis; anti-HBs test for immunity check.

Many adults simply choose to complete the series; it is a common and efficient approach. Your clinician can also check whether you have an active infection (hepatitis B surface antigen test) before vaccinating.

How does pregnancy affect hepatitis B vaccination?

Hepatitis B vaccination is safe during pregnancy and recommended if the pregnant person has not been vaccinated 1Ref 1Wodi AP, Issa AN, Moser CA, Cineas S (2025).Advisory Committee on Immunization Practices Recommended Immunization Schedule for Adults Aged 19 Years or Older — United States, 2025.Hepatitis B vaccination recommended for all adults through age 59 regardless of risk factors; risk-based groups for adults ≥60; birth dose recommendation. Infants born to people with hepatitis B need a specific preventive protocol at birth — both the vaccine and hepatitis B immune globulin (HBIG). The Heplisav-B two-dose formulation is not currently recommended during pregnancy due to insufficient safety data in that population 2Ref 2Weng MK, Doshani M, Khan MA, et al. (2022).Universal Hepatitis B Vaccination in Adults Aged 19–59 Years: Updated Recommendations of the Advisory Committee on Immunization Practices — United States, 2022.Universal hep B vaccination for adults 19–59 regardless of risk; Heplisav-B two-dose option at 0 and 1 month; Heplisav-B not recommended in pregnancy or hemodialysis; anti-HBs test for immunity check. Your obstetric provider manages this.