What’s the News: A daily dose of anti-HIV drugs can significantly reduce the likelihood that straight men and women will contract HIV from an infected partner, according to two new clinical studies. These studies add strong evidence to earlier findings that taking HIV drugs can prevent healthy people from contracting the disease, and are the first to show that the drugs reliably lower transmission risk in heterosexuals.

How the Heck:

One study enrolled 4,758 straight couples in Kenya and Uganda, in which one partner—either male or female—had HIV and the other didn’t.
The uninfected partners were split into three even groups. Each group was given a different type of pill, which they were instructed to take daily: a pill containing the antiretroviral drug tenofovir; a pill with both tenofovir and another HIV drug, emtricitabine; or a placebo.
Over course of the three-year study, 47 participants taking the placebo contracted HIV, compared with 18 taking tenofovir and 13 taking the combination pill—meaning that the drug ...