Abstract
BACKGROUND: Event-driven dosing of HIV preexposure prophylaxis (PrEP) using a 2-1-1 regimen is efficacious for men who have sex with men (MSM). However, data are limited on the prevalence, correlates, and patterns of nondaily PrEP use in the United States. SETTING: Nationwide online survey. METHODS: We distributed a survey to assess experiences with PrEP, including nondaily use, in May 2019 on geosocial networking sites commonly used by MSM. RESULTS: Among 9697 respondents, the mean age was 43 years, 67% were non-Hispanic white, and 90% were MSM. Nearly all (91.0%) had heard of PrEP, 40.1% ever used PrEP, and 33.3% used PrEP in the past 6 months. Most (60.6%) were interested in nondaily PrEP. Those without health insurance and those with higher incomes were more likely to be interested in nondaily PrEP. Of the 3232 who used PrEP in the past 6 months, 176 (5.4%) reported nondaily use. Fewer sexual partners, frequent sex planning, and substance use were associated with nondaily use. Common reasons for nondaily use were inconsistent sexual activity (59%) and cost (49%). The most prevalent regimen was event driven (48.3%); of those, 64.7% used 2-1-1. Of nondaily users, 24.0% used PrEP on a regular schedule but not every day, including only on weekends or days starting with T or S. CONCLUSIONS: Given substantial interest in nondaily PrEP, and use of nondaily strategies that have not been evaluated in clinical studies, there is a need for US public health authorities to provide guidance on safe and effective nondaily dosing for MSM.