Delany-Moretlwe S, Lingappa JR and Celum C. New Insights on Interactions Between HIV-1 and HSV-2.

Delany-Moretlwe S, Lingappa JR and Celum C. New Insights on Interactions Between HIV-1 and HSV-2. .

Herpes simplex type 2 (HSV-2) infection is common and frequently asymptomatic. Concerns exist about the high prevalence of HSV-2, particularly in areas of high HIV prevalence, because of observations that HSV-2 is associated with an increased risk of HIV acquisition, transmission, and disease progression. Several randomized trials have tested or are testing whether HSV-2 treatment can limit the spread of HIV, with mixed results. Although treatment with acyclovir, 400 mg twice daily, does not reduce HIV incidence, suppressive acyclovir and valacyclovir reduce HIV levels in plasma and in the genital tract. Ongoing trials are evaluating whether HSV suppression will reduce HIV transmission and disease progression. Until a protective HSV-2 or HIV vaccine is available, effective interventions that reduce the effect of HSV-2 on HIV transmission are critically needed.

Editors’ note: This excellent summary of what is known about the complex and bidirectional interactions between HIV-1 and herpes simplex virus–2 (HSV-2) was published before the May 8 th release of results from the multi-centre Partners in Prevention Study of 3408 discordant couples conducted in Botswana, Kenya, Rwanda, South Africa, Tanzania, Uganda and Zambia. To test whether HSV-2 daily suppressive therapy would reduce HIV transmission, HIV/HSV-2 co-infected partners were randomised to receive acyclovir 400 mg twice daily or matching placebo for 2 years while the uninfected partner was followed-up for HIV-1 seroconversion. Although acyclovir reduced the frequency of genital ulcers by 73% and HIV viral load by 40%, no significant difference was found in the rate of HIV transmission. A 17% reduction in HIV disease progression produced by low cost acyclovir was an intriguing result worthy of further study. With more than half a billion people infected with HSV-2, including up to 90% of people living with HIV, developing an HSV-2 vaccine continues to be a very high priority.