Taking Truvada (tenofovir disoproxil fumarate/emtricitabine) as pre-exposure prophylaxis (PrEP) against HIV can also prevent acquisition of hepatitis B virus (HBV), according to a recent study of men who have sex with men (MSM) in Japan, aidsmap reports.

Daisuke Mizushima, MD, of the National Center for Global Health and Medicine in Tokyo, presented findings from the retrospective cohort study of records regarding 591 MSM at the 2020 Conference on Retroviruses and Opportunistic Infections in Boston earlier this month. 

None of the men had had hep B previously or were living with HIV. One hundred forty-eight (25%) of the men took PrEP for at least part of the January 2018 to September 2019 follow-up period.

The men made quarterly clinic visits where they were screened for HIV and HBV.

The participants had an average age of 35 years old. According to their self-reports, 39% had been vaccinated against HBV, and 32% had antibody-based evidence that they had been vaccinated.

During the follow-up period, 14 of the men not on PrEP and one man on PrEP were diagnosed with hep B. This meant that overall, the HBV diagnosis rate was 3.57 infections per 100 cumulative years of follow-up.

The study authors estimated that taking Truvada as PrEP reduced the risk of acquiring HBV by 89%. (Daily use of Truvada lowers the risk of HIV by more than 99% among MSM.) By comparison, having been vaccinated against hep B only cut the risk of acquiring that infection in half.

The investigators stressed that receiving the hep B vaccine was nevertheless vital because it was associated with having a near symptomless course of infection with that virus.

To read the aidsmap article, click here.

To read the conference abstract, click here.