Birth Control Pills May Protect Women Against STIs

According to a recent study, popping contraceptive pills could protect against one of the most common sexually transmitted infections (STIs).

The McMaster University study in mice suggested that a female sex hormone, estradiol (E2), exerts its protective effect against herpes virus by shifting the immune response in the vaginal mucosa toward a more effective antiviral one.

Many studies have shown that injectable contraceptives containing progestins may increase a woman's risk of being infected with HIV and with HSV-2, the virus causing genital herpes. On the other hand, estradiol, another hormone that is present during the normal menstrual cycle and contained in oral contraceptives, has been shown to be protective.

To minimize unintended negative consequences of hormonal contraception, understanding how different hormones affect susceptibility to STI pathogens is important.

Researcher Charu Kaushic said that this is the first study that has shown how estradiol could be enhancing the immune system to fight against viral infection.

Kaushic added, "If this pathway can be verified in women, then we have laid the foundation to address a number of important public health issues, particularly whether some hormonal contraceptives may be better than others for women who are at higher risk of acquiring sexually transmitted infections, such as in Sub-Saharan African, where both HIV-1 and HSV-2 infection rates are high."

The researchers concluded that the study describes a mechanism by which E2 enhances anti-viral protection following vaccination in the genital HSV-2 mouse model.

They added, "to the best of our knowledge, this is the first study demonstrating that E2 can directly regulate T-cell mediated adaptive anti-viral immunity in the female genital tract by modulating DC functions."

The study appears in PLOS Pathogens.