More than 1.1 million Americans are living with HIV infection, and around 50,000 more people are infected every year. The infection is most commonly transmitted through sexual intercourse, meaning the race is on to find new methods of protection against the virus.
At present, those who are considered high-risk for HIV infection are prescribed daily pills called pre-exposure prophylaxis (PrEP) to protect against the virus.
But there have been advancements in topical HIV protection methods, mainly in the form of microbicides - gels or films containing HIV drugs than could be applied inside the vagina just before sex.