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WASHINGTON (Reuters) - A gel designed to protect women from
the AIDS virus made using Gilead Sciences' drug Viread could
protect men from infection during anal sex, British researchers
reported on Tuesday.
Tests on monkeys showed that a gel made using the drug,
known generically as tenofovir, may prevent AIDS transmission
when applied rectally.
The macaques pre-treated with rectal tenofovir gel up to
two hours before being given a monkey version of HIV were
partly or totally protected from infection, also rectally, Dr.
Martin Cranage of St. George's University of London and
colleagues reported.
Untreated animals and most of those treated with a placebo
gel, or treated with tenofovir gel after getting inoculated
with virus, became infected with the virus, called simian
immunodeficiency virus or SIV.
The study also added to evidence that the drug can protect
in various ways from infection with HIV if taken before
exposure -- some of the protected macaques developed T-cell
immune responses to the virus, they reported in the Public
Library of Science journal PLoS Medicine.
Many experts are pressing for the development of a
microbicide -- a gel or cream that could be applied vaginally
or rectally to protect against sexual transmission of the human
immunodeficiency virus that causes AIDS.
None are on the market now, although several are being
tested. Two versions use HIV drugs such as tenofovir, which is
usually taken as a pill to suppress the virus.
Last month mathematical experts published a study showing
that development of a microbicide would protect male sex
partners of such HIV-infected women.
Condoms prevent infection but many men refuse to use them.
Experts say women, and some men, need a private way to protect
themselves.
Florian Hladik of the Fred Hutchinson Cancer Research
Center and the University of Washington and Charlene Dezzutti
of the University of Pittsburgh, who were not involved with the
research, said tests in monkeys might not reflect real-life use
in human beings.
"High-risk behavior in humans is marked by repeated
exposures to the virus, which potentially will require
reapplication of the microbicide gel numerous times, possibly
over extended time periods," they wrote in a commentary.
This might damage the delicate mucous membranes in the
vagina or rectum, making transmission more, not less, likely,
they said.
An estimated 33 million people have HIV, mostly in Africa.
More than 60 percent of Africans with HIV are women who were
infected by their husbands or other male sexual partners.
Most of the 2 million people who get HIV every year
globally are women although men who have sex with other men
have, on average, 19 times the risk of most people of being
infected, according to research published this week at the
International AIDS Society meeting in Mexico City.
(Reporting by Maggie Fox; Editing by Julie Steenhuysen)
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