Twice-Yearly HIV Shot Shows Zero Infections in Trials

Scientists have developed an HIV prevention drug so effective that trials are reporting almost zero new infections among thousands of participants across seven countries.

Lenacapavir is a twice-yearly injectable medication that prevents HIV infection with just two shots per year. Two major studies called PURPOSE-1 and PURPOSE-2 have been tracking its effectiveness in women, men, and gender-diverse individuals in South Africa, Uganda, Argentina, Brazil, Mexico, Peru, Thailand, and the United States.

The results are remarkable. In the PURPOSE-1 trial focusing on women in South Africa and Uganda, researchers found zero new HIV infections during the first year of extended follow-up among participants receiving lenacapavir. More than 95% of participants who were initially taking daily oral pills chose to switch to the twice-yearly injection when given the option.

Dr. Noah Kiwanuka of Makerere University School of Public Health in Uganda said the absence of new infections shows the drug's high level of protection is maintained over time. Adherence rates stayed exceptionally high, with over 97% of participants keeping their twice-yearly injection appointments.

The PURPOSE-2 trial, which included a more diverse global population, recorded just one new HIV infection among lenacapavir users during the first 12 months of extended follow-up. That's one infection among thousands of participants at risk for HIV.

The drug has proven safe across all populations studied, with no new safety concerns identified during the extended trials. Participants reported finding the twice-yearly schedule much easier to maintain than daily oral medications.

The Ripple Effect

Health experts say lenacapavir could revolutionize HIV prevention globally if distributed equitably. Dr. Beatriz Grinsztejn, director of the HIV/AIDS Clinical Research Unit at Fiocruz in Brazil, called it "a breakthrough advance with the potential to accelerate global prevention progress."

The drug has already received regulatory approval in many parts of the world, and global rollout has begun. For communities where daily pill-taking presents challenges due to stigma, access, or adherence difficulties, a twice-yearly injection could be life-changing.

The high adherence rates suggest people prefer the long-acting option. When only two appointments per year stand between someone and HIV protection, the barrier to prevention drops dramatically.

With near-complete effectiveness and overwhelming acceptance from trial participants, lenacapavir represents one of the most powerful HIV prevention tools ever developed.