Researchers may have found a HIV preventative gel, which contains an AIDS drug already on the market, that could decrease a woman's chances of getting HIV in half. It was announced at the International AIDS Conference in Vienna, but further testing is required to make sure the product is safe and effective. 

AIDS has claimed 25 million lives total, and 33 million more are infected by HIV. Of this total, two-thirds are from sub-Saharan Africa. In this area, 60 percent of new infections develop among women and young females. 

For years, the only way to prevent HIV infection was by the use of condoms and male circumcision, since the foreskin contains cells that are "vulnerable to penetration by HIV." But the latter only prevents HIV infection in males. 

The study was led by Quarraisha Abdool Karim and Salim Abdool Karim from the Centre for the AIDS Programme of Research in South Africa (CAPRISA) in Durban. It consisted of almost 900 South African women who were sexually active and between the ages of 18 and 40, where 444 received a placebo and 445 received the microbicide gel. It was conducted in both the urban setting of Durban and the rural setting of Pietermaritzburg in the KwaZulu-Natal province.

Over a three year period, these women were asked to apply the gel, which contains a mixture of antiretroviral drugs and a one percent formulation of tenofovir that interrupts the reproduction of HIV in immune cells, with a vaginal applicator within a 12 hour window before intercourse and within a 12 hour window after intercourse. They were then tested for HIV on a monthly basis. In comparison to the placebo group, those who used the microbicide reduced the risk of HIV by 39 percent overall. For those who used the microbicide more often, as directed, 54 percent of the risk of HIV was reduced. 

"Without this gel, we may see 10 women becoming infected in a year," said Salim Abdool Karim. "With this gel, we would see only six women becoming infected."

While no major side effects were observed over the course of the study, the gel did become less effective after 18 months of use, and researchers are looking into finding out why. Right now, they believe it may be due to the fact that 40 percent of the women "used the microbicide less than one time out of two." Also, they will continue testing the gel to make sure there are no long term side effects that will exist beyond a three year period. 

The study has been published in the journal Science and could prove to be a vital part of finding efficient, preventative ways to avoid HIV infection everywhere.