Reducing H.I.V. by 90 Percent

Researchers found that the hundreds of gay men randomly assigned to take the drugs were 44 percent less likely to get infected than the equal number assigned to take a placebo.

But when only the men whose blood tests showed they had taken their pill faithfully every day were considered, the pill was more than 90 percent effective, said Dr. Anthony S. Fauci, head of the division of the National Institutes of Health, which paid for the study along with the Bill and Melinda Gates Foundation. … The bad news is that Truvada costs $12,000 to $14,000 in the U.S., although a generic version is available in the third world that costs just 40 cents a pill.