Herpes suppression leads to lower HIV viral load, says study

Active replication of the virus which causes genital herpes (HSV-2) causes HIV viral load to increase, and daily therapy to suppress HSV replication leads to a modest reduction in HIV viral load, according to a US study published in the Journal of Infectious Diseases.

The study, conducted by investigators at the University of Washington between 1994 and 1996 (before the introduction of HAART) involved 24 men and three women with detectable viral load (above 10,000 copies/mL), antibodies to HSV and no prior history of anti-HSV therapy.

The were two arms to the study, the first looking at the effect of HSV shedding on HIV viral load, even when no HSV lesions were present, and the second designed to see if HSV suppressive therapy consisting of 800mg of aciclovir taken three times daily was associated with lower amounts of HSV shedding and lower HIV viral loads.

Average follow-up was five months, and it was found that HIV viral loads were on average 32% higher when HSV was being shed, even when no symptoms of HSV were present.

Results from the second arm of the study showed that daily suppressive aciclovir therapy led, on average to a reduction of HIV viral load of 42%.

The investigators conclude that their study shows “that frequent...HSV reactivation is associated with higher levels of plasma HIV-1 RNA and that suppression of HSV is associated with a measurable decrease in plasma HIV-1 RNA levels.” They suggest that HIV treatment guidelines should be reviewed to take account of the suppression of HSV, adding that over time HSV suppression could be “associated with a measurable survival benefit.”

Although this study was conducted before the introduction of HAART, the investigators believe it still has value and that the “bursts of HIV replication” in people with HIV suppression may be associated with HSV reactivation.

It is possible that the real value of the study may be in resource limited setting where there is limited or no access to HAART. The investigators point out high HSV prevalence rates in South Africa and other countries with high HIV rates and limited health resources. Aciclovir is available in generic form and could therefore provide a relatively cheap treatment (less than 25 cents a day according to a recent UNICEF/UNAIDS/WHO/MSF survey of generic drug prices), which would also impact on HIV transmission rates, as a recent South African study found that recent HSV infection was associated with seroconconversion with HIV.

For more information on HSV click here.