Why it matters: Most HIV prevention depends on taking a daily pill, which is hard to sustain; a twice-yearly shot that prevents nearly all infections could change the trajectory of the epidemic if it can actually reach the people who need it.
Lenacapavir, an HIV-prevention injection given just twice a year, showed near-total protection in two phase 3 trials and is now beginning rollout in Africa a potential turning point, since most prevention requires a daily pill. In PURPOSE 1, in young women in sub-Saharan Africa, there were 0 HIV infections among 2,134 women on lenacapavir, versus 39 of 2,136 on Descovy and 16 of 1,068 on Truvada. In PURPOSE 2, across men and gender-diverse people, there were 2 infections among 2,179 participants 99.9% protected a 96% reduction versus background incidence. The FDA approved injectable lenacapavir, given every six months, as PrEP in June 2025 based on both trials. Most important limitation: the science is settled; access is not. Per a late-2025 U.S. State Department briefing, the 2026 rollout covers about 10 African countries against a manufacturing capacity near 600,000 doses far short of need (re-verify these figures). Cost and supply, not efficacy, now decide the impact.