New research has found an antibiotic that’s been around for decades could help prevent sexually transmitted bacterial diseases, according to a recent University of Washington clinical trial that proved so effective in certain populations it ended early.

Dr. Connie Celum, a UW professor of global health, medicine and epidemiology co-led the research.

Global health researchers at the University of Washington have received a $122 million grant from the Bill & Melinda Gates Foundation to test the effectiveness of the candidate drug islatravir, a once-a-month oral pill to prevent HIV.

The five-year grant will support the implementation of a Phase 3, randomized trial of islatravir, among women, in seven countries in sub-Saharan Africa. Islatravir is a nucleoside reverse transcriptase translocation inhibitor in development by Merck for the treatment and prevention of HIV-1 infection.

A monthly vaginal ring is one significant step closer to potentially becoming a new HIV prevention method for cisgender women in sub-Saharan Africa, who face persistently high rates of HIV infection but have few options to protect themselves.

Globally, 25 percent of new HIV cases occur among young women and adolescent girls in Africa. Pre-exposure prophylaxis, or PrEP, prevents infection when taken consistently, but stigma around the disease keeps some young women from maintaining usage, according to a new review by researchers at the University of Washington.