Evaluation of a pre-exposure prophylaxis programme for men who have sex with men and transgender women in Thailand: learning through the HIV prevention cascade lens

Introduction: Men who have sex with men (MSM) and transgender women (TGW) are two key populations (KPs) in Thailand at high risk for HIV. Uptake and scale-up of pre-exposure prophylaxis (PrEP) among them has been slow. We used data from Princess PrEP, Thailand’s largest KP-led PrEP programme, to operationalize PrEP service cascades. We identified gaps and pointed out where additional data are needed to inform a larger HIV prevention cascade. Methods: Numbers of people tested for HIV, tested HIV negative, eligible for PrEP (defined as any of the following in the past three months: condomless sex with partners of unknown/uncertain HIV status or antiretroviral treatment or viral load status, multiple partners, engaging in sex work, sexually transmitted infections, injecting drugs, using amphetamine-type stimulants, or repeated use of post-exposure prophylaxis), offered PrEP and accepted PrEP during January to November 2019 were retrieved from Princess PrEP database to inform PrEP service cascades for MSM and TGW. Reasons for not accepting PrEP were documented. Results: Of 6287 MSM who received HIV testing in Princess PrEP, 92.3% were HIV negative and 70.2% of them were eligible for PrEP. PrEP was offered to 94.7% of those eligible and 48.0% of those offered accepted it. Among 900 TGW who had HIV testing, 95.3% tested HIV negative and 64.8% of them met PrEP eligibility criteria. Of these, 95.0% were offered PrEP and 43.9% of them accepted it. Among MSM and TGW who met PrEP eligibility criteria, no or low-HIV-risk perception was the most common reason provided (46.7% of 2007 MSM and 41.9% of 296 TGW) for not accepting PrEP. Conclusions: PrEP service cascades from the Princess PrEP programme identified no or low-risk perception as key barrier to PrEP acceptance among MSM and TGW who met PrEP eligibility criteria. More implementation research studies are needed to explore PrEP motivation and access in larger communities outside of clinical services. This is to identify gaps and strategies to address them within motivation, access and effective use domains of the HIV prevention cascade.