Doctors have long
suspected that people with herpes are more likely to
catch HIV. So they thought that by treating herpes, they
could also cut a person's HIV risk.
But a new study
that tested this strategy found the assumption may have
been wrong.
"It's a
significant, disappointing finding," Francis Ndowa,
coordinator of the sexually transmitted infections control
team at the World Health Organization, said in an
interview.
Ndowa was not
connected to the research, published Friday in the medical
journal The Lancet.
The finding may
spark a rethinking of HIV prevention strategies in
Africa, where controlling sexually transmitted diseases such
as herpes is usually part of general AIDS prevention
plans.
Researchers
tracked more than 3,000 men and women infected with herpes
in Africa, Peru and the United States. Roughly half
were treated with aciclovir, an antiviral that stops
herpes ulcers.
After a year and
a half, the scientists found that 75 people out of the
1,581 who had been receiving aciclovir were later infected
with HIV. Of the 1,591 people who received placebo
pills, 64 contracted HIV.
In the trial,
researchers chose participants who had herpes and who faced
similar risks of getting AIDS. The study also questioned the
participants during monthly visits about risky sexual
behavior with their recent partners.
The study was
paid for by the United States' National Institute of
Allergy and Infectious Diseases, other U.S. government
institutes, and by GlaxoSmithKline PLC, which sells
aciclovir as Zovirax.
A small study in
Tanzania last year also suggested that treating herpes
didn't help reducing HIV susceptibility.
But that doesn't
necessarily mean that the theory of treating herpes to
avoid HIV is incorrect, experts said.
"It's probably
likely that we need considerably more potent
interventions than we have," Connie Celum, a professor of
global health and medicine at the University of
Washington who led the Lancet study, told The
Associated Press.
Experts said
there was a complex relationship between the two viruses
that is still not entirely understood.
When herpes
ulcers erupt, that draws white blood cells to the skin to
fight the virus. Unfortunately, those white blood cells also
have receptors for HIV.
Ndowa said it was
possible that even without the telltale ulcers, herpes
might have lingered while patients were taking the
aciclovir, allowing HIV to gain a foothold.
In an
accompanying commentary in the Lancet, Ronald H. Gray and
Maria J. Wawer of Johns Hopkins University said it was
questionable whether controlling sexually transmitted
infectious could work to prevent HIV.
"It is time to
reassess the hypothesis and to adjust prevention
policy accordingly," they wrote.
But Ndowa and
Celum said the strategy of fighting herpes to prevent AIDS
might work, if a different dosage or more powerful drug was
tried.
"We don't exactly
know why this didn't work, but this approach still has
potential," Ndowa said. "Maybe it was just too much to
expect from a tablet taken twice a day that it could
be effective against HIV." (AP)
