Individuals who are clinically assessed to be at similar risk of HIV acquisition (>2 per 100 person-years) as HIV-negative individuals with a serodiscordant partner who is not known to be virally suppressed (<200 copies per ml) are considered to be eligible for HIV Pre-Exposure Prophylaxis (PrEP) in England. In order to support clinicians in making this assessment, we used HIV incidence estimates from surveillance data to define risk groups who may benefit from PrEP in England.
We reviewed longitudinal data from GUMCAD, the national sexually transmitted infections (STI) surveillance system in England, on attendees at sexual health clinics. The incidence of HIV per 100 person-years (95% confidence intervals) for attendees with a history of HIV testing, post-exposure prophylaxis for HIV (PEPSE), bacterial STIs or use of drugs in a sexual context before or during last sexual intercourse was determined using the Kaplan-Meier method. Separate analyses were performed for MSM and heterosexuals.
Among MSM, the incidence of HIV was greatest in those who were diagnosed with infectious syphilis (4.5) in the past year followed by those prescribed at least one course of PEPSE (3.9) in the past year and by those diagnosed with a bacterial STI (3.6) in the past year and by those who used drugs in a sexual context (3.6) before or during the last sexual intercourse (Table 1). Among heterosexuals, the HIV incidence was below 1 per 100 person-years in all the sub-groups included (Table 1).
More heterosexuals than MSM are diagnosed with HIV outside the sexual health clinics, so in this study the incidence in the heterosexual group is underestimated. However, given the high degree of variability in HIV risk among MSM and heterosexuals, these findings provide evidence to guide clinical risk assessment an essential step to accessing PrEP. This may help clinicians target patients more efficiently, thus maximising the impact of PrEP