Rectal gel could limit HIV transmission

When applied as part of a rectal gel, the drug tenofovir may prevent HIV transmission, according to an study performed in macaque monkeys. These results were released on August 4, 2008 in the open access journal PLoS Medicine.

Rectal intercourse carries a very high risk of HIV transmission and there has been little research on topical measures to prevent this. To investigate this potential new preventative measure, Martin Cranage of St. George'ss University of London and colleagues performed a study in macaque monkeys. After application of the experimental gel, a placebo, or no medication, human rectal exposure to HIV was simulated in the monkeys by exposure to simian immunodeficiency virus (SIV), a form of the disease that is specific to monkeys.

The researchers found that the macaques pre-treated with rectal tenofovir gel up to two hours before viral exposure were partly or totally protexted from SIV infection. Untreated animals, along with those treated with the placebo were infected with the virus. Notably, some of the macaques given protection also developed T-cell immune responses to the virus.

Further studies are needed before research can start in humans.