Vaccine and Infectious Disease Division

The long-term transmission risk of HSV-2 infection

Herpes simplex virus 2 (HSV-2) is a common and persistent infection.  HSV-2 is one of the most common STDs in the world, and is known to significantly increase the chances of HIV acquisition.  The symptoms it causes, primarily genital ulcers, can be treated with medication, but it is impossible to eradicate the virus completely from the body. The virus periodically reactivates from its dormant state in genital neurons, traffics to genital skin cells, and can be detected on the genital surface when infected cells burst (also known as “shedding”).   Studies from VIDD researchers and other scientists have shown that HSV-2 shedding in recently infected people is frequent and often occurs in the absence of noticeable symptoms.  However, the natural history of long-term HSV-2 infections remained poorly understood.

VIDD Research Associate Dr. Warren Phipps and other VIDD scientists addressed this knowledge gap by studying the detailed shedding patterns of 377 people with HSV-2 infection, more than 70 percent of whom had been infected for at least one year.  The study volunteers collected genital swabs daily for at least 30 days, which the researchers then tested for the presence of HSV DNA.  The scientists found that rates of HSV shedding were somewhat lower in subjects who had been infected for more than one year, but these people still showed frequent bouts of viral reactivation, and the amount of virus they shed was still high enough to pose a significant transmission risk.  These findings suggest that HSV-2 transmission is an ongoing risk in infected people, and treatments to reduce viral shedding and transmission should address this long-term risk.

Phipps W, Saracino M, Magaret A, Selke S, Remington M, Huang ML, Warren T, Casper C, Corey L, Wald A.  Persistent genital herpes simplex virus-2 shedding years following the first clinical episode.  J Infect Dis. 2011 Jan 15;203(2):180-7.