Hepatitis B Vaccination for Family Contacts
All household and sexual contacts of persons identified as HBsAg-positive should be vaccinated immediately. 1
Immediate Actions for Family Contacts
Test all household and sexual contacts for HBsAg, anti-HBs, and anti-HBc before vaccination, but do not delay the first vaccine dose—administer it immediately after collecting blood for testing. 1 This approach ensures contacts are protected as quickly as possible while identifying those who may already be infected or immune.
Who Qualifies as a Family Contact Requiring Vaccination
- Household contacts: Anyone living in the same residence as the HBsAg-positive person 1
- Sexual partners: All current and recent sexual contacts 1
- Needle-sharing contacts: Persons who share injection equipment 1
Vaccination Protocol
Standard Three-Dose Series
Administer hepatitis B vaccine at age-appropriate doses using the standard schedule: 0,1, and 6 months. 1
- Adults and children >10 years: 1.0 mL per dose 1
- Infants and children ≤10 years: Age-appropriate dosing per manufacturer guidelines 1
Alternative Four-Dose Schedule
For contacts needing rapid protection, use the accelerated four-dose schedule with doses at 0,1,2, and 12 months. 1 This provides earlier protection after the first three doses.
Post-Vaccination Testing
Test anti-HBs levels 1-2 months after completing the vaccine series for all household and sexual contacts of HBsAg-positive persons. 1, 2 This is critical because these contacts remain at ongoing risk and need documented immunity.
Interpreting Results
- Anti-HBs ≥10 mIU/mL: Protective immunity achieved, no further action needed 1, 2
- Anti-HBs <10 mIU/mL: Non-responder requiring revaccination 1, 2
Management of Non-Responders
For contacts with anti-HBs <10 mIU/mL after the primary series, administer a complete second three-dose series and retest 1-2 months after the final dose. 1, 2 Most non-responders (44-100%) will develop protective antibodies after a second complete series. 2
If Still No Response After Second Series
- Test for HBsAg to rule out chronic infection 1
- Counsel about need for HBIG postexposure prophylaxis for any known or likely exposure to the HBsAg-positive household member 1
- Emphasize prevention measures: Use condoms if sexual partner, avoid sharing personal items that could have blood contact (toothbrushes, razors) 1, 3
Special Considerations for Infants Born to HBsAg-Positive Mothers
Administer both HBIG (0.5 mL) and hepatitis B vaccine within 12 hours of birth, preferably immediately after physiologic stabilization. 4 Efficacy decreases markedly if treatment is delayed beyond 48 hours. 4
- Complete the vaccine series: Doses at birth, 1 month, and 6 months 4
- Test infant at 9-15 months: Check HBsAg and anti-HBs to confirm protection 3
- If anti-HBs <10 mIU/mL: Give one additional vaccine dose and retest; if still inadequate, complete a second full series 1
Prevaccination Testing Considerations
Prevaccination testing for HBsAg, anti-HBs, and anti-HBc is recommended for household and sexual contacts to identify those already infected or immune, but testing should never delay vaccination. 1 This is cost-effective in populations with higher prevalence of prior HBV exposure.
When to Skip Prevaccination Testing
- Young children without prior exposure risk: Proceed directly to vaccination 1
- Situations where testing would delay vaccination: Administer first dose immediately 1
Critical Pitfalls to Avoid
The most common failure in hepatitis B prevention is inadequate follow-through with contact vaccination—only 13-20% of eligible contacts complete vaccination in real-world practice. 5 To improve outcomes:
- Actively identify and document all household and sexual contacts at the time of HBsAg-positive diagnosis 1
- Provide direct referrals rather than general recommendations 5
- Schedule vaccination appointments before the contact leaves the clinic 5
- Conduct culturally sensitive counseling in the patient's primary language 1
Ongoing Protection Measures
Even after vaccination, counsel HBsAg-positive patients to notify contacts, use condoms with non-immune partners, avoid sharing personal items with blood contact, and cover cuts and wounds. 1, 3
What Does NOT Transmit HBV
HBV is not spread by breastfeeding, kissing, hugging, coughing, sharing food or utensils, or casual touching. 1, 3 Children with HBV should not be excluded from school, daycare, or activities unless prone to biting. 1, 3
Postexposure Prophylaxis for Unvaccinated Contacts
If an unvaccinated household or sexual contact has a known exposure to the HBsAg-positive person, administer HBIG (0.06 mL/kg) and begin the vaccine series within 14 days of exposure. 4 For sexual contacts, this window is critical—efficacy drops significantly after 14 days. 4