New Lines of Attack in H.I.V. Prevention
via New York Times, by Donald G. McNeil, Jr.
Because 95 percent of gay American men and 40 percent of heterosexual American women have had anal sex at least once during their lifetimes, according to surveys, rectal versions of the gel are being developed. Tests of new, less viscous formulations that are less likely to draw water into the rectum, making use unpleasant, will begin soon, said Dr. Ian McGowan, another leader of microbicide trials at the University of Pittsburgh’s medical school.
Gay and bisexual black and Hispanic men, who are now the highest AIDS risk groups in the United States, will be recruited soon in Boston, Pittsburgh and Puerto Rico to see if they find the gels acceptable, he said.
But first it is crucial to make sure gels don’t inflame the rectal lining, which is more fragile than the vagina’s. Since H.I.V. zeros in on activated immune cells, inflammation increases infection risk. Brief tests of irritation and acceptability will be done on people advised to remain celibate during the tests, he added. Larger trials, in which thousands of men and women regularly practicing anal sex are given gel or placebo will not begin for two to three more years.
“The rectal microbicide field is about 10 years behind the vaginal one,” Dr. McGowan said.
That is partly due to misconceptions.
“When you mention rectal microbicides, a lot of people say ‘Oh, come on,’ because they think you have to protect the whole colon, and it’s meters long,” Dr. McGowan said. In fact, researchers believe protecting only the last six to eight inches will suffice.
A 2008 British study showed that rectal tenofovir gel was very protective in monkeys that were then given anal doses of the virus that causes simian AIDS.