The importance of PrEP persistence in preventing HIV infections on PrEP.

We are pleased to learn that our paper’s themes resonated with other contexts such as the authors’ pre‐exposure prophylaxis (PrEP) programme in Sydney, Australia. We are also interested to learn that there is similarly limited awareness and resources supporting PrEP 2‐1‐1/on‐demand dosing [1] in Australia. Anecdotally, several of our PrEP patients are considering transitioning to PrEP 2‐1‐1 dosing during ongoing shelter‐in‐place in response to the COVID‐19 epidemic, but are worried their clinicians may not support it.

We agree that stigma related to PrEP or sexual behaviour [2, 3, 4] is an important factor that may interfere with PrEP persistence (consistent use of PrEP during periods with potential HIV exposure) [5]. Participants in this analysis did not report stigma related to being a man who has sex with men (MSM) as a factor in their PrEP gaps, but two participants discussed stigma related to the image of PrEP as a medication for people with multiple sexual partners, and at least one participant feared disclosure of her PrEP use to her partner as she felt it might imply she had outside partners [6].

We agree with the authors that PrEP uptake is an important component of the PrEP cascade, and will be crucial towards meeting global targets to reduce HIV transmission [7, 8]. As the design of this analysis involved a sample of all individuals who had used PrEP at any point in our health system, we were not able to interview individuals who HIV seroconverted and had never used PrEP before. In an analysis within another integrated health system in Northern California, barriers to PrEP use among those who were aware of PrEP prior to HIV diagnosis but never started it included: cost/insurance issues, perceived low risk for HIV acquisition and concerns about being stigmatized if they used PrEP [9]. In San Francisco in 2017, approximately 40% of MSM had used PrEP in the last six months, whereas 50% reported condomless anal sex over the same time period [10]. We, however, found in a prior analysis that the relative risk of PrEP discontinuation is unfortunately increasing over time, potentially because later versus early adopters are more ambivalent about using and remaining on PrEP [11]. As more individuals try PrEP in our jurisdiction and others, we will need to turn our focus towards intervenable factors that can support PrEP persistence. In order to maximize PrEP’s prevention efficacy, individuals will need to remain on PrEP with adequate adherence during periods of HIV exposure. We agree that there is no time to waste in addressing potential barriers to implementation of this highly effective, but still underutilized, HIV prevention intervention.

COMPETING INTEREST

The authors have no conflicts of interest to report.

AUTHORS’ CONTRIBUTIONS

MAS drafted the letter. NL, PK, RW, HMS, NW, AYL, MG and SPB revised the letter for content. All authors have read and approved the final manuscript of the letter.