Landmark study shows treating both partners for bacterial vaginosis improves outcomes, but experts suggest there may be more to the story.

"We’ve suspected for a long time that it’s a sexually transmitted infection (STI)," one of the researchers said.

Bacterial vaginosis is a poorly understood infection that affects one in three women and can bring with it uncomfortable symptoms and, sometimes, long-term health complications. Treatment is often unsuccessful, with 60 percent of B.V. cases recurring within a year, keeping women stuck in a disruptive cycle of going on and off antibiotics.

Health experts say an Australian study linking sexual activity to an infection that 1 in 3 U.S. women contract has provided a new tool to prevent recurrences, as well as find a cure.

For decades, bacterial vaginosis has been treated as a women’s health issue—but new research suggests treating male partners could dramatically cut recurrence rates.

Women experience fewer repeat infections with bacterial vaginosis when both they and their male sex partners receive antibiotics.