Researchers of HIV and AIDS have long known that semen has an enhancing quality on the infectiousness of HIV, as it causes the virus cells to cluster together and bind themselves to certain protein strands within the semen fluids, thus increasing their ability to attach to – and infect – host cells. This is a major reason, researchers have learned through studies, why anal sex has the highest risk potential in the transmission of HIV from one person to another. The other major reason for the high risk involved in anal sex is rupturing of anal tissue during intercourse, which causes bleeding and raises the infection potential for both partners. Recently, researchers learned that semen is further problematic in stopping the spread of HIV, as it has been shown to lessen certain antiretroviral microbicide’s effectiveness against HIV.

An antiretroviral microbicide is a new form of anti-HIV gel which is meant to be applied to the vaginal walls prior to sexual intercourse, and which was proven to effectively eliminate the HIV cells – either by killing them or causing them to be unable to bind to any host cells – but this success is only seen in the laboratory. When they started clinical trials in areas of Africa with high infection rates, they noticed that not only were the microbicides ineffective in stopping infection, sometimes they seemed to have the reverse effect, causing it to be more likely for infection to occur. They now know why this happened. The microbicide’s effectiveness against HIV was compromised by proteins within the semen which, while strengthening the HIV cell’s infectiousness, caused the microbicides to be up to twenty times less effective against stopping transmission of the virus. The researchers who conducted the study that lead to this observation are hoping to help women in the Sub-Saharan countries of Africa who, many times, have no choice about safe sex or condom use. If they can work around the negative effects of semen, which some new antiretroviral microbicides are already promising, they can help curb the spread of the disease, in these countries and around the world. As one of the authors of the study says, “This study sheds light on why these microbicides did not work, and it provides us with a way to fix this problem by creating a new compound drug combining antivirals and amyloid inhibitors.” The more they know about each step of the infection process, the more they can break these steps down and stop HIV transmission.