The US Food and Drug Administration has just approved lenacapavir, an injectable form of HIV prevention that is almost 100 percent effective and requires only two doses per year. In clinical trials, lenacapavir proved to be 99.9 percent effective in preventing HIV infection through sexual transmission in people weighing more than 35 kilograms. Lenacapavir has already been approved in some countries as a treatment for HIV in people with forms of the virus that are resistant to other treatments. It’s hoped the long-lasting effects of lenacapavir will make it easier for people to stay protected against the virus. Updated 6-20-2025 3:30 pm BST: Details of Gilead Science’s strategy for providing access to lenacapavir in low- and lower-middle-income countries were added.