Author: Harney B, Stoové M, van Santen DK, O’Reilly M, Sasadeusz J, Iser D, Hellard M, Doyle J on behalf of the co-EC study investigators

Theme: Epidemiology & Public Health Research Year: 2019

Background: Hepatitis B virus (HBV) has been reported among gay and bisexual men globally and
can be transmitted through both sexual exposure and injecting drug use (IDU). HBV vaccination is
recommended for people living with HIV and/or hepatitis C. We aimed to examine HBV immunity
and susceptibility among people living with HIV/hepatitis C co-infection.
Methods: Data were drawn from co-EC, a prospective study at three primary care clinics, two
hospitals and one sexual health centre, aiming to treat and eliminate hepatitis C among people living
with HIV. HBV serological data were extracted from clinical records and if not available, HBV serology
was performed. Modified Poisson regression with robust variance was used to explore factors
associated with HBV susceptibility.
Results: Among 200 participants recruited for HCV treatment, 197 were male. During the study 133
males reported sex with ≥1 other males and 62 reported IDU in the six months prior to enrolment.
HBV serology was available for 186 participants with 105 (57%) having documented evidence of
prior hepatitis B immunity (HBsAb titre >10 iU). A further 81 (43%) underwent HBV surface antigen
(HBsAg) and/or core antibody (HBcAb) testing, of whom 27 (36%) were HBcAb positive and HBsAg
negative, indicating immunity due to infection rather than vaccination.
Overall 42/186 participants (23%) were both HBcAb and HBsAg negative and classified as HBV
susceptible. The prevalence of HBV susceptibility was higher among people enrolled at primary care
sites (n=32) compared to sexual health centre or tertiary sites (n=10) (Adjusted Prevalence Ratio
2.89, 95% Confidence Interval 1.51-5.50, p=0.001).
Conclusion: In this cohort, approximately one quarter of people living with HIV/HCV co-infection
were susceptible to HBV infection at enrolment. The serological data available suggests that many
participants may have acquired their immunity through infection rather than vaccination. Efforts to
increase HBV vaccination are warranted, particularly in primary care settings.
Disclosure of Interest Statement: Investigator initiated funding was received from Bristol MyersSquibb for co-EC. The funders had no input in these analyses or the decision to submit.

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