What are the recommended testing and treatment protocols for an asymptomatic individual exposed to Hepatitis B (HBV)?

Hepatitis B Testing and Management After Exposure in Asymptomatic Individuals

For an asymptomatic person exposed to Hepatitis B, immediately initiate baseline testing with total anti-HBc and administer the first dose of hepatitis B vaccine (plus HBIG if the source is HBsAg-positive), then perform follow-up testing at 6 months with HBsAg and total anti-HBc to detect seroconversion. 1

Immediate Post-Exposure Actions (Within 24 Hours)

Baseline Testing

• Draw baseline serologic testing immediately after exposure consisting of total anti-HBc 1
• This baseline establishes whether the exposed person had prior HBV infection before the exposure occurred 1

Immediate Prophylaxis Based on Source Status

If source is HBsAg-positive:

• Administer hepatitis B vaccine first dose immediately (preferably within 24 hours) 1
• Add HBIG (0.06 mL/kg) if the exposed person is unvaccinated or known non-responder to prior vaccination 2
• The maximum effective interval for prophylaxis is 7 days for percutaneous exposure and 14 days for sexual exposures 1

If source is HBsAg-negative:

• Complete the hepatitis B vaccine series according to standard schedule (0,1, and 6 months) 1
• No HBIG is needed 1

If source HBsAg status is unknown:

• Initiate hepatitis B vaccine series with first dose immediately 1
• HBIG is not required for unknown source exposures 2

Follow-Up Testing at 6 Months

Perform follow-up serologic testing approximately 6 months after exposure consisting of: 1

• HBsAg (to detect chronic infection) 1
• Total anti-HBc (to detect acute or resolved infection) 1

This 6-month window captures the incubation period and allows detection of HBV infection that may have been transmitted during the exposure 1

Post-Vaccination Antibody Testing

Test for anti-HBs 1–2 months after the final (third) dose of the vaccine series to document immune response 1, 3

Key Testing Parameters:

• Target protective level is anti-HBs ≥10 mIU/mL 1, 3
• Use quantitative assay (ELISA) to measure the protective threshold 3
• Critical caveat: If HBIG was administered, wait 4–6 months after HBIG before testing anti-HBs, as passively acquired antibodies interfere with accurate assessment of vaccine-induced immunity 3

Management of Non-Responders (Anti-HBs <10 mIU/mL):

• Administer a second complete 3-dose vaccine series 1, 2
• Retest anti-HBs 1–2 months after the final dose of the second series 1, 2
• Approximately 30-50% of initial non-responders will achieve protective levels after revaccination 2

Precautions During Follow-Up Period

The exposed person does not need to modify daily activities during the 6-month follow-up period: 1

• No need to modify sexual practices or avoid pregnancy 1
• Breastfeeding mothers do not need to discontinue 1
• No modifications to work responsibilities are necessary 1
• However, refrain from donating blood, plasma, organs, tissue, or semen during the follow-up period 1

Common Pitfalls to Avoid

• Do not delay baseline testing or first vaccine dose – both should occur immediately after exposure, preferably within 24 hours 1
• Do not test anti-HBs too early after HBIG administration – wait 4–6 months to avoid falsely elevated results from passive antibodies 3
• Do not skip the 6-month follow-up testing – this is essential to detect seroconversion even in asymptomatic individuals 1
• Do not use qualitative anti-HBs tests – only quantitative assays can confirm the protective threshold of ≥10 mIU/mL 3

Special Considerations for Healthcare Personnel

For healthcare workers with documented prior vaccination but unknown immune status: 1

• Measure anti-HBs upon exposure 1
• If anti-HBs <10 mIU/mL, give one booster dose first, then retest 1–2 months later 2
• This approach is more practical than administering a full second series immediately 1