05/07/08

Herpes treatment: another blow for HIV prevention

Before AIDS, the sexually active teen’s STD joke-of-choice was “What’s the difference between love and herpes?” The answer, of course, was that herpes was for ever. And so it was, although antiviral therapy, acyclovir in particular, has proven quite good at suppressing it and at reducing outbreaks which often lead to genital ulcers. But those, including me, who beloved suppressing herpes would prevent HIV are sadly disappointed by recent research.

A gaggle of studies have shown that people with Herpes Simplex Virus Type 2 (HSV-2, or genital herpes to most of us) are more likely to get infected with HIV, in part because they are more likely to have ulcers that open the door to HIV. So it was perfectly logical to think that if we suppressed the herpes, we’d have fewer new HIV infections.

The first study, among high risk women in Tanzania, was not encouraging. Now a much larger study among women in South Africa, Zambia and Zimbabwe and gay men in Peru and North America have confirmed the gloom. Treating people’s herpes doesn’t seem to make any difference to the risk of getting HIV. The study ticked all the “gold standard” boxes for this sort of research — it was double-blinded, randomised and placebo-controlled. It had a couple of weaker points, as all studies do. Ethically, researchers had to treat any episodes of herpes they saw on examination with a burst of acyclovir, regardless of the patient’s placebo status (which researchers of course didn’t know). But that doesn’t seem to be enough to skew the results.

This is a huge disappointment (and so far somewhat inexplicable). It’s important, though, to remember that this only looked at one side of the equation: people who have (the highly infectious) HSV-2 but don’t yet have (the much less infectious) HIV. The other side is people who already have both infections. It is still possible that regular antiviral treatment will make it less likely that they’ll pass either or both infections on to their sex partners.

The other thing to get depressed about was the very high rates of new infection in the study. These people had endless amounts of counseling and condoms. They had their STIs treated. They had better access to prevention services than most. And still, 4.0% of the African women, 3.5% of the men in Peru and 2.3% of the men in the US got infected (or, to be more precise for those who care about these things, the incidence rate was 4, 3.5 and 2.3 per 100 person years). If that’s the best we can manage with intensive prevention services, we’re still in a LOT of trouble.

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This post was published on 05/07/08 in Science.

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  1. Comment by mohdzawi, 07/07/08, 04:20:

    Is there any study done in Malaysia? I bet it is as bad as in other nations.

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