WWW- The AIDS virus quickly spreads from the mouth to the rest of the body, a monkey study shows.

The finding means a new hurdle for AIDS vaccines. It suggests they’ll have to work quickly and efficiently to prevent HIV infection.

The finding also raises new questions about the safety of oral sex, suggests study leader Donald L. Sodora, PhD, assistant professor of internal medicine, infectious diseases, and microbiology at the University of Texas Southwest Medical Center in Dallas.

“We have highlighted unappreciated entry points for the AIDS virus,” Sodora tells WebMD. “The study shows that oral exposure to HIV is a way a person can hypothetically be infected. We know babies get infected from HIV in breast milk. So it is not a big stretch to think semen could infect you orally. … I don’t think this is a safer way to have sex.”

Humans vs. Monkeys

Kimberly Page-Shafer, PhD, MPH, notes that Sodora’s study looked at monkeys inoculated with high doses of the monkey version of the AIDS virus. That may be very different from what happens in humans. Oral sex only rarely spreads HIV from person to person, she says.