Asymptomatic HVS-2 Individuals Can Spread the Virus
April is STD Awareness Month, an appropriate time for the Journal of the American Medical Association to publish the results of a new study which showed individuals with an asymptomatic herpes simplex virus type 2 (HSV-2) infection can spread the virus through sexual contact.
Anna Wald, MD, MPH, of the University of Washington in Seattle, and colleagues conducted the study to evaluate the virologic and clinical course of HSV genital shedding among individuals with symptomatic and asymptomatic HSV-2 infection.
The authors write, “The issue of infectivity is both a patient management and a public health concern. The primary concern of many HSV-2–seropositive persons is the risk of transmission to sexual partners; in our experience this is the main source of angst in patients with genital herpes.”
The study involved 498 immunocompetent HSV-2–seropositive persons (410 symptomatic, 88 non-symptomatic) enrolled in prospective studies of genital HSV shedding at the University of Washington Virology Research Clinic, Seattle, and Westover Heights Clinic, Portland, Oregon, between March 1992 and April 2008. Each participant obtained daily self-collected swabs of genital secretions for at least 30 days.
The rate of viral shedding was measured by quantitative real-time fluorescence polymerase chain reaction for HSV DNA from the genital swabs.
The researchers found HSV-2 was detected twice as often among those with a symptomatic infection (20.1% versus 10.2% of days, P
Subclinical shedding (days on which virus was shed in the absence of lesions) rates were higher in persons with symptomatic infection compared with asymptomatic infection (13.1% vs 8.8%, P
However, the amount of HSV detected during subclinical shedding episodes was similar in both groups -- 4.3 and 4.2 log10 copies, respectively (P=0.27).
Wald and colleagues note this “underscores the epidemiologic observations that the risk of HSV-2 transmission is high from persons with unrecognized HSV-2 infection."
Herpes simplex virus type 2 (HSV-2) is one of the most frequent sexually transmitted infections worldwide, with global estimates of 536 million infected persons and an annual incidence of 23.6 million cases among persons aged 15 to 49 years.
In the United States, 16% of adults are HSV-2 seropositive, but only 10% to 25% of persons with HSV-2 infection have recognized genital herpes. Moreover, most HSV-2 infections are acquired from persons without a clinical history of genital herpes.
Several methods have been identified that can partly reduce the risk of HSV-2 transmission to sexual partners. Condom use, daily valacyclovir therapy, and disclosure of HSV-2 serostatus each approximately halve the risk of HSV-2 transmission.
If you don’t know your HSV-2 status, then valacyclovir therapy and disclosure aren’t options. Condom use is. Protect yourself and your partner.
Tronstein E, et al "Genital shedding of herpes simplex virus among symptomatic and asymptomatic persons with HSV-2 infection" JAMA 2011; 305: 1441-1449.