Can a patient with a positive Hepatitis B (HBV) core antibody and a non-reactive Hepatitis B surface antigen start Pre-Exposure Prophylaxis (PrEP) for HIV prevention?

PrEP Initiation in Patients with Positive Hepatitis B Core Antibody and Negative Surface Antigen

Yes, patients with a positive hepatitis B core antibody (anti-HBc) and negative hepatitis B surface antigen (HBsAg) can safely start PrEP for HIV prevention, but require appropriate monitoring of hepatitis B status during treatment.

Understanding the Serologic Pattern

• The serologic pattern of positive anti-HBc with negative HBsAg typically indicates past HBV infection with recovery and immunity, or rarely, a "low-level" chronic infection 1
• This pattern can also represent a false positive result, passive transfer to infants born to HBsAg-positive mothers, or past infection with subsequent loss of detectable antibodies 1
• When this pattern is accompanied by positive hepatitis B surface antibody (anti-HBs ≥10 mIU/mL), it confirms recovery from past infection with immunity 1, 2

PrEP Recommendations for Patients with HBV Exposure History

• The International Antiviral Society-USA (IAS-USA) recommends hepatitis B surface antigen (HBsAg) testing prior to initiating PrEP in all individuals 1
• For patients with positive anti-HBc and negative HBsAg, PrEP can be initiated as the medications used (tenofovir disoproxil fumarate/emtricitabine) are active against both HIV and HBV 1
• Tenofovir-based PrEP regimens are actually beneficial for patients with evidence of prior HBV infection, as they provide protection against potential HBV reactivation 3

Monitoring Recommendations

• Baseline hepatitis B testing should include HBsAg, anti-HBs, and anti-HBc to fully characterize HBV status before starting PrEP 1
• For patients with evidence of prior HBV infection (positive anti-HBc), liver function tests should be monitored during PrEP use 1
• If the patient has detectable HBV DNA (even at low levels), more careful monitoring is warranted as there is a small risk of viral reactivation 4

Important Considerations and Precautions

• The FDA label for tenofovir disoproxil fumarate includes a boxed warning about the risk of severe acute exacerbations of hepatitis B upon discontinuation of therapy 3
• If PrEP is discontinued in patients with evidence of prior HBV infection, hepatic function should be monitored closely for several months 3
• The risk of clinically significant HBV reactivation in patients who are HBsAg-negative but anti-HBc-positive is generally low (0.8-2.5%) but requires awareness 4

Algorithm for PrEP Initiation in Patients with Positive Anti-HBc

1. Confirm complete HBV serologic profile (HBsAg, anti-HBc, anti-HBs) 1
2. If HBsAg is negative and anti-HBc is positive:
   • Check anti-HBs status to determine if immunity is present 1
   • Consider HBV DNA testing if there are concerns about occult HBV infection 4
3. Initiate standard PrEP regimen with tenofovir disoproxil fumarate/emtricitabine 1
4. Monitor liver enzymes at baseline and periodically during treatment 1
5. Counsel patient about the importance of adherence and the potential risks of abrupt discontinuation 3

Conclusion

Patients with positive hepatitis B core antibody and negative surface antigen can safely start PrEP. The medications used for PrEP (particularly tenofovir-based regimens) are active against both HIV and HBV, providing dual protection. However, appropriate monitoring and awareness of the small risk of HBV reactivation, especially upon discontinuation, are essential components of care.