What is the recommended post‑exposure prophylaxis for hepatitis B?

Post-Exposure Prophylaxis for Hepatitis B

For unvaccinated persons or vaccine non-responders exposed to HBsAg-positive blood, administer both HBIG (0.06 mL/kg) and hepatitis B vaccine simultaneously at separate anatomic sites as soon as possible, preferably within 24 hours. 1

Immediate Actions Based on Vaccination Status

Unvaccinated or Incompletely Vaccinated Persons

• Administer HBIG (0.06 mL/kg intramuscularly) plus hepatitis B vaccine first dose immediately when the source is HBsAg-positive or unknown, ideally within 24 hours but up to 7 days for percutaneous exposures. 1, 2

• Give the vaccine and HBIG at separate anatomic sites to ensure optimal immune response. 1

• Complete the remaining vaccine doses on schedule (at 1 month and 6 months after the first dose). 1

Fully Vaccinated with Documented Response (anti-HBs ≥10 mIU/mL)

• No treatment is necessary for persons with documented protective antibody levels. 2

Fully Vaccinated Without Documented Response

• Administer a single vaccine booster dose immediately if the source is HBsAg-positive. 1

• Measure anti-HBs levels 1–2 months after the booster to confirm protective response (≥10 mIU/mL). 2

• If anti-HBs remains <10 mIU/mL after the booster, administer HBIG and consider the person a non-responder requiring HBIG with future exposures. 2

Healthcare Workers with Unknown Immune Status

• Measure anti-HBs immediately upon exposure and give one booster dose if anti-HBs <10 mIU/mL, then retest 1–2 months later. 2

Timing Considerations

The effectiveness of prophylaxis diminishes significantly with delayed administration, though efficacy may extend up to 7 days post-exposure for needlestick injuries. 1 Recent evidence from Korea suggests that HBIG administered between 24 hours and 7 days postexposure may be as effective as administration within 24 hours in preventing occupational HBV infection. 3

Do not delay HBIG administration while waiting for source testing—start prophylaxis immediately if high suspicion exists. 1

Special Exposure Types

Sexual Exposure

• Administer a single dose of HBIG (0.06 mL/kg) within 14 days of last sexual contact with an HBsAg-positive person. 1

• Initiate the hepatitis B vaccine series if the exposed person is unvaccinated. 1

Perinatal Exposure

• Infants born to HBsAg-positive mothers should receive HBIG 0.5 mL intramuscularly within 12 hours of birth and hepatitis B vaccine 0.5 mL within 7 days of birth. 1

Unknown Source Exposures

• Unvaccinated persons should receive the hepatitis B vaccine series initiated within 24 hours. 1

• HBIG may be considered if the exposure setting suggests high risk (e.g., visibly blood-stained needle in a high-prevalence area). 2

Baseline and Follow-Up Testing

Immediate Baseline Testing

• Draw total anti-HBc immediately after exposure to establish whether the exposed person had prior HBV infection before the exposure occurred. 2

• Document hepatitis B vaccination history and prior vaccine response. 2

Follow-Up Testing Schedule

• Perform follow-up serologic testing approximately 6 months after exposure, consisting of HBsAg and total anti-HBc to detect seroconversion. 2

• Test for anti-HBs 1–2 months after the final (third) dose of the vaccine series to document immune response, with a target protective level of anti-HBs ≥10 mIU/mL. 2

• If HBIG was administered, wait 4–6 months after HBIG before testing anti-HBs to avoid falsely elevated results from passive antibodies. 2

Management of Non-Responders

Approximately 30–50% of initial non-responders will achieve protective levels after revaccination with a second complete three-dose series. 2

For confirmed non-responders (anti-HBs <10 mIU/mL after two complete vaccine series), HBIG must be administered with every future HBsAg-positive exposure. 2

Critical Pitfalls to Avoid

• Do not test discarded needles or syringes for virus contamination—this is unreliable and not recommended; focus on testing the source patient when possible. 1, 4

• Do not confuse hepatitis B protocols with hepatitis C—there is no immunoglobulin or vaccine for hepatitis C, and no post-exposure prophylaxis is available for HCV. 1

• Do not assume immunity without documentation—verify vaccination response status, especially for healthcare personnel and immunocompromised individuals. 1

• Do not delay prophylaxis for low-risk exposures—the risk of HBV transmission without prophylaxis may exceed 30% after exposure to HBeAg-positive blood. 4