Pre-exposure prophylaxis (PrEP) with emtricitabine/tenofovir to prevent HIV in individuals with hepatitis B virus (HBV) raises concerns about HBV reactivation when stopping event-driven PrEP or redundancy in HBV treatment for continuous PrEP (since tenofovir alone would be enough for HBV). Real-world data from PrEP services could provide useful epidemiological information on HBV prevalence in PrEP attendees in low-prevalence countries.
A retrospective analysis on PrEP attendees of three services in northern Italy were conducted to assess HBV prevalence among PrEP attendees and the need for primary cycle/booster dose HBV vaccination despite previous vaccination during childhood (at birth or 12 years). Risk factors possibly associated with HBV exposure were evaluated with a binary logistic regression analysis, controlling for age, gender, place of birth (Italy vs abroad) and chemsex use (as a proxy of high-risk sexual behaviour for contracting sexually transmitted infections).
Among 10 hepatitis B surface antigen (HBsAg)-positive out of 2152 PrEP attendees (0.46%), PrEP was started in 7 subjects mainly with a daily schedule, 1 has declined after counselling, 2 were lost to follow-up. Around three-fourth of the 2152 PrEP attendees were born in Italy after 1979, thus were previously vaccinated during childhood. The probability of needing a booster for low-titre HBs antibodies was higher among those vaccinated at birth with respect to those vaccinated at 12 years (OR 2.30, 95% CI 1.80 to 2.96). The risk of previous HBV exposure (resulting in either HBsAg+ or antibodies against HBV core antigen [HBcAb]+) was higher for increasing age (OR 3.07, 95% CI 2.49 to 3.78 per 10 years more) and lower for being born in Italy (OR 0.23, 95% CI 0.14 to 0.36).
Our real-world data on a large PrEP cohort suggest that, although uncommon, HBV infection in PrEP users in low-prevalence countries should be considered and managed. In addition, HBV screening offers the opportunity to expand prevention services through vaccination.