Published online: 8 February 2006
Since
the late 1980s, anecdotal evidence has suggested that circumcision can
make men less likely to catch HIV from infected partners. The inner
lining of the male foreskin can hold nine times more virus than the
outer layers of the penis, and is the main entry point for HIV. Some
doctors have suggested that cutting off the virus's gateway to the body
could dramatically curb infection rates in men.
Now,
researchers from the Johns Hopkins Medical Institutions in Baltimore,
Maryland, say that it might also benefit women. They say that women
with circumcised partners are 30% less likely to become infected,
because they are less exposed to the virus.
Ronald
Gray led the project, which studied the medical records of more than
300 Ugandan couples from 1994 to 2001. At the beginning, all the men
involved were HIV positive, whereas all the women were HIV negative. Of
the men, 44 were circumcised and 299 were not. The medical records show
that the average annual rate of female HIV infection was 6.6% if they
had circumcised partners, compared with 10.3% if the men were
uncircumcised.
This
suggests that the circumcision of young males in the general African
population could have protective effects for both men and women, the
team says. They present their conclusions today at the 2006 Conference
on Retroviruses and Opportunistic Infections in Denver, Colorado.
Further trials
Although
the study may provide a promising lead for public-health researchers,
its findings will have to be confirmed by full medical trials before
circumcision can be recommended for all men. "There are all sorts of
issues about the quality of this information," warns Jimmy Volmink,
director of the South African Medical Research Council's Cochrane
Centre in Tygerberg. "It is not a trial, it is a review of medical
records," he says, and a statistical review of medical records such as
this does not account for factors such as hygienic or sexual practices.
"The
strength of a clinical trial is that you can be relatively sure the
group is balanced and there are no other factors intervening," says
Volmink.
Preliminary
findings from the Ugandan review spurred researchers to instigate just
such a clinical trial: this involves circumcising half of the 5,000 men
in the study and then monitoring rates of HIV infection in the men and
their partners. The trial is due to end in 2007.
Bigger picture
Trials
of male circumcision and HIV in Kenya and South Africa have not
monitored its effect on women, because of the difficulty of linking and
tracking two people, says Steven Reynolds, part of the Johns Hopkins
team.
In
2005, French and South African researchers called an early halt to a
trial held in Orange Farm near Johannesburg, because outcomes were so
favourable (see 'Caution on circumcision cuts South Africa's AIDS researchers').
Officials considered it unethical to continue after uncircumcised men
were shown to be 60% more likely to become infected than circumcised
men.
But
the results of this trial are still questioned by some AIDS
researchers. "In trials, numbers of participants jump around quite a
lot and we don't have a final result for this one," says Volmink. "It
is prudent to await results before making policy decisions."
Even
if the benefits of circumcision can be proved, it may be difficult to
persuade some to accept it as standard practice. And public-health
officials should be aware that a sudden rise in circumcisions that are
not medically supervised could even lead to an increase in infections,
adds Volmink.