2+2+1

The World Health Organization (WHO) updates its guidance for pre-exposure prophylaxis (PrEP) in men who have sex with men to include event-driven PrEP (also known as “on-demand” PrEP and “2+1+1”) in addition to daily PrEP. This follows trial results from the Prévenir study, which found that both on demand and daily PrEP are safe and effective in protecting against HIV infection. The guidance does not recommend event-driven PrEP for women, transgender women or men who have vaginal and/or anal sex with women.