Abstract:
Background: Pre-exposure prophylaxis (PrEP) is efficacious for African women at risk
for HIV, but data on adherence outside clinical trials are sparse. We describe the
persistence and execution of PrEP use among women participating in a large open-label
PrEP demonstration project, particularly during periods of HIV risk.
Setting and methods: Three hundred ten HIV-uninfected women in HIV serodiscordant
couples in Kenya and Uganda were offered and accepted PrEP. Electronic monitoring
caps were used to measure daily PrEP adherence. Time on PrEP while at risk for HIV
(when the HIV-infected partner was on antiretroviral therapy <6 months) and weekly
adherence while on PrEP were calculated and compared among older and younger (<25
years old) women.
Results: As defined above, women were at risk for HIV for an average of 361 days; 54%
took PrEP during their entire risk period and 24% stopped but restarted PrEP during their
risk period. While on PrEP, women took ≥6 doses/wk for 78% of weeks [67% of weeks
for women aged <25 years, 80% of weeks for women aged ≥25 years (P < 0.001)], and
≥4 doses for 88% of weeks [80% for those <25, 90% for those ≥25, (P < 0.001)].
Compared with historical, risk-matched controls, HIV incidence was reduced 93% (95%
confidence interval: 77% to 98%) for all women and 91% (95% confidence interval: 29%
to 99%) among women aged <25 years.
Conclusion: Women, including young women, in HIV-serodiscordant couples took PrEP
successfully over sustained periods of risk. Although young women had lower adherence
than older women, they achieved strong protection, which suggests that women can align
PrEP use to periods of risk and imperfect adherence can still provide substantial benefit.