HIV Pre-Exposure Prophylaxis (PrEP) purchase patterns and STI occurrence among Israeli men: A cohort analysis

BACKGROUND: HIV Pre-exposure prophylaxis (PrEP) is the regular use of antiretroviral medication by people who are not infected with HIV to prevent seroconversion. Israel approved PrEP for continuous use in 2017, and Israeli Health Maintenance Organizations (HMO) offered PrEP with a copayment to eligible members. METHODOLOGY: This retrospective cohort study included all people who were dispensed PrEP between September 2017 to June 2019 in the second largest HMO in Israel. Statistical analysis, including Kaplan Meier, was conducted to evaluate user PrEP purchase, adherence to medical follow-up, and clinical outcomes. RESULTS: In total, a cohort of 757 PrEP users were followed for 657.8 person-years. All but one user were male; median age was 35 years. At baseline, 0.8% had gonorrhea and 1.5% had chlamydia infections and 4.4% had recent syphilis infection. Continuous use of PrEP (without interruption/discontinuation) was observed in 29.9%, while 39.9% interrupted and 30.3% discontinued use. Median time to first interruption/discontinuation was 4.0 months. At 6–12 months after initiation, 79.8% of users had a documented HIV test, 77.3% a Chlamydia-Gonorrhea panel, and 78.9% a creatinine test. There was one new case of HIV among the cohort, five months after PrEP discontinuation. Estimated first-year infection rates were 5.0%, 8.6% and 6.8% for gonorrhea, chlamydia and first-time syphilis, respectively. CONCLUSIONS: This study shows heterogeneous PrEP purchase patterns and required medical follow-up, and an increase in STIs among consistent PrEP users. Improving adherence to recommended medical follow-up during PrEP use is essential in PrEP’s integration into Israel’s national HIV prevention strategy.