A team of South African scientists (pictured above) received three standing ovations at the XVIII International AIDS Conference on Tuesday, following their research presentation in Vienna.

They had achieved what many researchers feared might never happen: They'd created an HIV-fighting vaginal gel experts say has the potential to "alter the course of the HIV epidemic."

Here's how it works: an HIV-negative woman would apply the microbicide – which contains the potent antiretroviral drug Tenofovir – just before and after intercourse. Early tests have shown that doing this would cut her chance of acquiring the virus by 39 percent. It would also cut her risk of being infected by herpes by more than 50 percent.

For husband-and-wife epidemiologists Salim and Quarraisha Abdool Karim (pictured), who in 10 years conducted seven failed trials for the study, these encouraging results -- based on their research in urban and rural South Africa -- could not have come at a better time.