Hepatitis B is one of the most important vaccine-preventable infectious diseases worldwide. Unlike hepatitis A, hepatitis B has the potential to become a lifelong infection, leading to serious liver complications such as cirrhosis and liver cancer. Fortunately, highly effective vaccines and post-exposure treatments have dramatically reduced the burden of disease.
Understanding how hepatitis B spreads, who is at risk, and when vaccination is recommended is essential for preventing infection and protecting long-term liver health.
Hepatitis B is caused by the Hepatitis B virus (HBV), a small double-stranded DNA virus that infects liver cells. Diagnostic testing relies on two key viral markers:
Unlike hepatitis A, HBV is not spread through the fecal-oral route. Transmission occurs through parenteral or mucosal exposure to infected blood and body fluids (semen, vaginal secretions, saliva) via sexual contact, shared injection equipment, or percutaneous injuries.
The incubation period averages 90 days (typical range: 60 to 150 days), allowing asymptomatic individuals to unknowingly transmit the virus.
While most healthy adults clear acute HBV infection, approximately 5% to 10% progress to chronic hepatitis B. Chronic carriers remain infectious and are at high risk for severe long-term sequelae, including liver cirrhosis, chronic liver failure, and primary hepatocellular carcinoma. Acute infection can also precipitate severe liver failure in patients with pre-existing liver disease.
Transmission from mother to child during pregnancy or delivery represents a critical infection pathway. Without preventive intervention, 40% of infants born to infected mothers develop chronic hepatitis B, and 25% of affected children ultimately die from liver complications. Consequently, all pregnant women must undergo HBsAg screening during their first prenatal visit.
The hepatitis B vaccine is a non-infectious recombinant vaccine that achieves protective immunity in 90–95% of healthy adults and ~98% of full-term infants.
| Clinical Parameter | Recommendations & Protocols |
|---|---|
| Primary Contraindication | Severe anaphylactic reaction to baker’s yeast. |
| Post-Vaccination Testing (Anti-HBs) | Indicated for high-risk groups (healthcare workers, infants of HBsAg+ mothers, dialysis patients, HIV/immunocompromised). Target protective level is ≥10 mIU/mL. |
| Booster Requirements | Not routinely needed for immunocompetent individuals. Hemodialysis patients require annual anti-HBs testing with a booster if levels drop below 10 mIU/mL. |
| Vaccination Status | Recommended Action Plan |
|---|---|
| Unvaccinated | Administer Hepatitis B Immune Globulin (HBIG) and initiate vaccine series, ideally within 24 hours. |
| Fully Vaccinated (Untested Anti-HBs) | Administer a single vaccine booster following exposure to an HBsAg-positive source. |
| Partially Vaccinated | Administer HBIG if indicated and complete remaining vaccine doses. |
Significant bloodborne exposures also warrant concurrent evaluation for HIV, Hepatitis A, and Hepatitis C.
Hepatitis B is a major bloodborne pathogen requiring proactive management. Universal prenatal screening, routine immunization, antibody verification for high-risk workers, and rapid post-exposure HBIG plus vaccination are essential strategies to prevent chronic liver disease and primary liver cancer.
