Tuesday, July 16, 2013

The risk of HIV transmission

The risk of HIV transmission during anal intercourse may be around 18 times greater than during vaginal intercourse, according to the results of a meta-analysis published online ahead of print in the International Journal of Epidemiology.

Moreover, as well as this empirical work, the researchers from Imperial College and the London School of Hygiene and Tropical Medicine carried out a modelling exercise to estimate the impact that HIV treatment has on infectiousness during anal intercourse. They estimate that the risk of transmission from a man with suppressed viral load may be reduced by as much as 99.9%.

Anal intercourse drives the HIV epidemic amongst gay and bisexual men. Moreover a substantial proportion of heterosexuals have anal sex but tend to use condoms less frequently than for vaginal sex, and this may contribute to heterosexual epidemics in sub-Saharan Africa and elsewhere.

Rebecca Baggaley and colleagues conducted a systematic review and meta-analysis (an analysis of all the medical research that meets predefined requirements) of the risk of HIV transmission during unprotected anal intercourse. The same authors have already conducted similar reviews of the transmission risk during vaginal sex and oral sex.

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