Control of HSV-2 Infections Could Help Prevent HIV Spread
Originally published by Reuters Health, January 7, 2002
NEW YORK (Reuters Health) — Efforts to lower STD rates to reduce the incidence of HIV infection need to include control of herpes simplex virus type 2 (HSV-2) as well as bacterial pathogens if the strategy is to succeed, University of Washington researchers suggest.
Drs. Anna Wald and Katherine Link conducted a literature search in which they found 31 studies that identified the risk of HIV infection in persons seropositive for HSV-2. Their findings appear in the Journal of Infectious Diseases for January 1.
The Seattle-based researchers estimated the relative risk of HIV infection to be 2.1 when HSV-2 infection preceded that with HIV. The odds ratio when the sequence of infections was unknown was 3.9.
"Among HSV-2-seropositive persons, 52% of sexually transmitted HIV infections can be attributed to HSV-2 infection," Drs. Wald and Link write.
They note that "population attributable risk percentage" varies with HSV-2 seroprevalence in a population. For example, HSV-2 seroprevalence is 22% in the general population in the US, where 19% of sexually transmitted HIV infections can be attributed to HSV-2. Among commercial sex workers, four out of five individuals may be seropositive for HSV-2, and nearly half of HIV infections can be attributed to herpes.
"A trial of suppressive antiherpes therapy in persons who are at high risk for HIV acquisition may clarify the role of HSV-2 in the spread of HIV infection," the researchers suggest. If such a trial validated the concept, they add, generic acyclovir may be a practical tool in the fight against HIV.
Simply asking patients to refrain from sex when they have noticeable lesions is not practical, Dr. Wald commented to Reuters Health. "The problem is that most people who have herpes don't know that have it or even that they have a lesion. The only way to know is through an HSV-2 blood test."
Even if the individual is aware of a lesion being present, "it is not clear that the elevated risk is only at the time of a noticeable lesion," Dr. Wald pointed out. "There may also be higher risk at subclinical stages or during asymptomatic reactivation of the virus, which presumably is associated with microscopic ulcerations."
She noted that accurate HSV-2 antibody tests are now commercially available. Therefore, "people who are at risk for HIV should be routinely tested for HSV-2 to further define their risk of HIV infection," Dr. Wald suggested.
