The University of Washington School of Medicine has announced a five-year, $122 million grant from the Bill & Melinda Gates Foundation to test the effectiveness of a once-a-month oral pill to prevent HIV.

The grant will support the implementation of a Phase 3 randomized trial of islatravir — a nucleoside reverse transcriptase translocation inhibitor in development by Merck for the treatment and prevention of HIV-1 infection — among women in Eswatini, Kenya, Malawi, South Africa, Uganda, Zambia, and Zimbabwe. The study to evaluate the efficacy and safety of a monthly oral medication compared with a daily preventive pill among healthy, HIV-uninfected cisgender women also will include test sites in the United States.

While the current standard of care, daily oral pills, effectively protects those who use it consistently from HIV infection, the ability of people to adhere to that regimen is a major concern. A paper published by Connie Celum, a UW professor of global health, medicine, and epidemiology who is the study's lead investigator, and her colleague Jared Baeten found that some of the greatest doubts about taking a pre-exposure prophylaxis were voiced by young African women, who account for approximately 25 percent of new HIV infections globally.

"This could be a game-changer," said Celum. "The whole field is moving toward less adherence-dependent and easier strategies for users of HIV prevention....For some people, a daily pill is easy. But when you're talking about populations where sexual activity is stigmatized, particularly young African women, men who have sex with men, or female sex workers, there are a lot of barriers to taking a pill a day."