Male circumcision protects women from AIDS: study

By Maggie Fox, Health and Science Correspondent

DENVER (Reuters) – Male circumcision, which has been shown
to protect men from infection with the AIDS virus, appears to
protect women, too, U.S. and Ugandan researchers reported on
Wednesday.

Circumcising men reduced infections in their female
partners by 30 percent, the researchers found. One said the
difference may be related to the structure of the foreskin,
which is removed in circumcision.

In the study of more than 300 Ugandan couples in which the
man infected the woman, the researchers found that 299 women
caught HIV from uncircumcised partners and only 44 were
infected by circumcised men.

Circumcision also reduced the risk of infection with other
sexually-transmitted diseases such as trichomonas and bacterial
vaginosis, but not syphilis, gonorrhea or chlamydia, the
researchers told an AIDS meeting in Denver.

Dr. Thomas Quinn of Johns Hopkins University in Baltimore
has been leading a team that studies 12,000 volunteers in
Rakai, Uganda. They have been studying transmission of the
human immunodeficiency virus that causes AIDS.

Last year they reported that circumcised men were less
likely to become infected with HIV. Now, they told the
Conference on Retroviruses and Opportunistic Infections, it
appears that among infected men, circumcision reduces the
likelihood they will transmit the virus through sex.

They also presented more evidence that circumcision
protects men. They reanalyzed previous studies and found that
circumcision reduced the risk of HIV infection in men by 50
percent — and by 70 percent in the highest-risk men.

The findings will have to be confirmed in other groups
before being used as the basis for recommendations, Quinn said.
However, he said, “early indications are dramatic.” If borne
out, for every 15 to 60 circumcisions, one case of HIV
infection could be prevented, he said.

Circumcision’s benefits may stem from the structure of the
foreskin of the penis. Its inner lining, or mucosa, carries
cells that are vulnerable to the AIDS virus.

“Also that mucosal layer does not have the thick keratin
(skin) that the outside skin of the foreskin has,” Oliver
Laeyendecker, who worked on the study, said in an interview.

“Not only do you have more virus there because of the types
of cells that are there, but the barrier is easier to go
through from the man to the woman on that skin surface because
it doesn’t have to go through a lot.”

The AIDS virus is transmitted by semen, blood and breast
milk and via sex, shared needles or other contacts with
infected blood.

Semen can transmit the virus, but levels in the semen drop
over time, while remaining elevated in the blood, Laeyendecker
said.

The theory is that the virus can pass in tiny amounts of
blood in the foreskin. “Because of the nature of that membrane,
because it is thin, because it is susceptible to micro-tears,
you have a lot of openings,” Laeyendecker said.

“Plus you have more cells with virus there, so it lends
itself to being a more transmissible surface.”

The AIDS virus infects close to 40 million people globally,
most of them in Africa. It kills 3 million people a year and
infects 5 million new people every year.

It is eventually fatal and there is no cure or vaccine,
although drug cocktails can keep patients healthy for years.
Laeyendecker said the Uganda volunteers have access to at least
some of the drugs through a U.S. program.