Hepatitis B is a serious liver infection caused by the Hepatitis B virus (HBV). It can cause acute or chronic illness, leading to severe complications like cirrhosis and liver cancer. The virus spreads through contact with infected bodily fluids (blood, semen, vaginal fluids), commonly via sexual contact, sharing needles, or from mother to child during birth. Vaccination is a highly effective and safe method to prevent Hepatitis B infection.
Vaccination in Infancy
Universal infant vaccination is a primary approach to preventing Hepatitis B. Newborns typically receive a three-dose vaccine series, with the first dose administered promptly after birth, ideally within 24 hours. This initial dose is important for preventing transmission from an infected mother to her baby. Subsequent doses are given at 1-2 months and 6-18 months of age to complete the series.
Infants born to mothers who test positive for Hepatitis B Surface Antigen (HBsAg) require additional protection. Along with the first vaccine dose, these infants receive Hepatitis B Immune Globulin (HBIG) shortly after birth, preferably within 12 hours. HBIG provides immediate, temporary antibodies, while the vaccine stimulates the baby’s own immune system for long-term protection. This early intervention is important because about 90% of infants infected at birth can develop chronic Hepatitis B, increasing their risk for liver disease later in life.
Adolescent and Adult Vaccination
For adolescents and adults not vaccinated in infancy or whose vaccination history is uncertain, vaccination is a recommended preventive measure. The standard adult schedule consists of three doses administered over six months, typically at 0, 1, and 6 months. This series helps establish long-term immunity against the virus.
An alternative two-dose schedule is available for adults aged 18 and older using a specific vaccine called Heplisav-B. This vaccine involves two doses given one month apart, offering faster completion of the series. Catch-up vaccination is important for unvaccinated individuals to protect against infection and associated health issues.
Specific Risk Factors for Vaccination
Certain individuals face a higher risk of Hepatitis B infection or severe outcomes, making vaccination important regardless of age. These groups include:
- People with multiple sex partners or those seeking treatment for sexually transmitted infections.
- Individuals who inject drugs.
- Healthcare and public safety workers, due to potential exposure to blood and bodily fluids.
- Individuals with chronic liver disease (e.g., cirrhosis, Hepatitis C) or end-stage renal disease (including hemodialysis patients).
- Household contacts and sexual partners of individuals with chronic HBV infection.
- Travelers to countries where Hepatitis B is common, and individuals with HIV infection.
Navigating Missed Doses and Immunity
If a dose in the Hepatitis B vaccine series is missed, there is no need to restart the entire series. The remaining doses should be administered as soon as possible to complete the schedule. For instance, if the second dose is missed, it should be given as soon as possible, with the third dose following at least eight weeks later.
For most healthy individuals who complete the full vaccine series, immunity against Hepatitis B is long-lasting, often lifelong. Routine booster doses are not recommended because the immune system retains memory of the virus, allowing a rapid protective response if exposed. However, post-vaccination serologic testing (antibody testing) may be recommended for certain high-risk individuals, such as healthcare workers or immunocompromised persons, to confirm adequate immunity. This testing occurs 1-2 months after the final dose.