An article in Clinical Infectious Diseases suggests that women infected with the herpes simplex virus type 2 (HSV-2) may have an increased risk of transmitting the virus to others if they use hormonal contraceptives or have certain bacterial vaginal infections.
HSV-2 can remain latent in the body for long periods, but when it becomes active and begins to multiply ("shedding"), it becomes transmissible to others, particularly through sexual activity. Additionally, evidence suggests that HSV-2 infection can increase the risk of HIV transmission.
As suggested by a prior study, the researchers found that the use of oral hormonal contraceptives is linked with genital tract shedding of HSV-2. However, they also found that two common types of bacterial infections, bacterial vaginosis (BV) and vaginal Group B streptococcus (GBS), were related to an increased risk of HSV-2 shedding, an association that had not previously been made. Vaginal yeast infections were not associated with increased shedding risk.
The findings could have significant implications, says Thomas Cherpes, lead author of the study.
"Because hormonal contraceptives are used by millions of people throughout the world, even a modest association with HSV-2 shedding would provide a significant contribution to the burgeoning genital herpes epidemic," he said. Dr Cherpes added that further research is also required to determine if the type of contraceptive affects shedding frequency.
The finding that some vaginal bacterial infections are also linked to a higher frequency of HSV-2 shedding could be important in controlling the spread of HSV-2. "BV is an infection that is readily treatable, and treatment for it is effective," Dr Cherpes said. "I believe that treatment of BV will be shown to be an effective therapy to reduce the risk of HSV-2 shedding, but, again, further work is required."
Since there is no cure for genital herpes, controlling its transmission is the only option. Women who have HSV-2 should consider alternate forms of contraception, such as condoms. And because there is no vaccine available for genital herpes, treating the bacterial infections that could predispose women to higher HSV-2 shedding frequency is probably one of the best ways to keep the virus in check, according to Dr Cherpes.