Aids Study Says Oral Sex Isn’t Safe Sex

Oral sex has been considered relatively safe in the age of AIDS. But Harvard researchers warn in a new study that it may not be.

When scientists at Harvard’s Dana-Farber Cancer Institute put drops of SIV, the monkey form of the AIDS virus, into the mouths of seven adult monkeys, six became infected and developed AIDS-like illnesses.

The study, reported today in the journal Science, is the first to demonstrate that adult monkeys can be infected orally.

If further studies support the findings, the results could trigger a change in AIDS prevention efforts and risk-reduction counseling.

Public health officials have previously warned that performing oral sex on men who don’t wear condoms carried a small risk for contracting the human immuno-deficiency virus (HIV), which causes AIDS. But prevention efforts have always focused on unprotected vaginal or anal sex, which are much more risky.

In the nation’s gay communities, many AIDS educators promote oral sex - even without a condom - as “safer sex.” But the new research calls that into question.

“This should be a warning that unprotected oral sex is not safe sex,” said Ruth M. Ruprecht, an oncologist at Dana-Farber and associate professor of medicine at Harvard.

Ruprecht emphasized that her findings did not imply that HIV could be transmitted in human saliva by kissing, sharing eating utensils, or sharing toothbrushes.

She said saliva contains an insignificant concentration of HIV compared to the semen or blood of an infected person. There is even new evidence that saliva contains a molecule that may inhibit HIV.

Several scientists warned against overreacting to the Harvard findings, saying more research would be needed before the study could be applied to humans.

There have been no more than two dozen documented cases worldwide in which someone contracted HIV by oral sex, according to the scientific literature on AIDS. And several large studies tracking the health of thousands of gay men have turned up scant evidence of HIV infection through oral sex.

Most of the infections of HIV among gay men stem from unprotected anal sex, according to the federal Centers for Disease Control and Prevention, which tallies AIDS cases.

The Harvard scientists, working with researchers from Tufts and Tulane Universities, compared the group of adult macaque monkeys who were given SIV orally with a group of monkeys exposed rectally.

To their surprise, they discovered that the minimum dose needed to infect the monkeys orally was 6,000 times lower than the minimum dose needed to infect them through the anus.

Ruprecht said all the monkeys used in the experiment were healthy. They did not have cuts, lesions or sores in the mouth or anus that might have provided easy access to the bloodstream.

She said it was not clear exactly how the SIV reached the animals’ blood. Her hypothesis is that the gateway might be through cells on the tonsils.