Is your radar up regarding herpes risk?

Results of a new study indicate patients who have tested positive for herpes simplex virus type 2 (HSV-2) but don't have symptoms or genital lesions still experience virus shedding during subclinical episodes.1 What is the implication for healthcare providers? It's time to increase screening for genital herpes, because there is a high risk of transmission from persons with unrecognized HSV-2 infection.

To conduct the study, researchers compared the rates and patterns of genital HSV shedding in 498 immunocompetent HSV-2-seropositive persons 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, defined as the presence of virus that is actively replicating and can be transmitted to another person, was measured by polymerase chain reaction, a testing method for viral DNA.

Study data indicate the bulk of days of shedding in persons with asymptomatic HSV-2 is unrecognized, and people might engage in sexual activity not knowing that they are at risk for transmitting the virus to sexual partners.1

How can people take preventive measures if they do not know their HSV status? asks Anna Wald, MD, MPH, professor of medicine, epidemiology and laboratory medicine at the University of Washington in Seattle. Wald served as lead author of the current analysis. Providers need to realize that patients are interested in being tested, says Wald. Before preventive strategies can be employed, patients need to know their infection status, she states.

Robert Hatcher, MD, MPH, professor of gynecology and obstetrics at Emory University School of Medicine in Atlanta, reminds providers that there are five sexually transmitted infections for which young men and women are at risk, all of which are transmitted more than 50% of the time by a completely asymptomatic person infected with herpes, HPV, hepatitis B, HIV, or chlamydia. For this reason, condoms should be used almost routinely by young, sexually active couples, he advises.

Look closely at results

In performing the analysis, researchers report that HSV-2 was detected on 4,753 of 23,683 days (20.1%) in 410 persons with symptomatic genital HSV-2 infection, compared with 519 of 5,070 days (10.2%) in 88 persons with asymptomatic infection. Genital HSV was detected at least once in 342 of 410 persons (83.4%) with symptomatic HSV-2 infection and in 60 of 88 (68.2%) persons with asymptomatic infection.

Subclinical genital shedding rates were higher in persons with symptomatic infection compared with asymptomatic infection (2,708 of 20,735 [13.1%], compared to 434 of 4,929 [8.8 %]), researchers note. The median amount of HSV detected during subclinical genital shedding episodes was similar in persons with symptomatic and asymptomatic infection, they observe.

Patients with symptomatic infection had more frequent genital shedding episodes (median 17.9 episodes per year) compared with persons with asymptomatic infection (12.5 episodes per year), the analysis shows. Days with lesions accounted for 2,045 of 4,753 days (43.0%) with genital viral shedding among persons with symptomatic genital HSV-2 infection, compared with 85 of 519 days (16.4%) among persons with asymptomatic infection.

Why don't more providers test for genital herpes? There are no recommendations to routinely test for HSV-2, says Wald.

While there are type-specific antibody tests that distinguish HSV-1 from HSV-2, there are important testing tricks and details that providers need to know before they begin expanded testing/screening, says study co-author Terri Warren, RN, NP, owner of the Westover Heights Clinic in Portland, OR. There also are excellent new types of swab tests that put cultures to shame in terms of sensitivity, she states. (The American Social Health Association of Research Triangle Park, NC has developed several helpful provider resources for herpes testing. To access them, visit the organization's web site, and click on "Herpes Resource Center." At the center web page, you can click on "Herpes Blood Test Guide" to download a free two-page listing of tests. Also at the center web page, you can check out other testing resources by selecting "The Herpes Testing Toolkit online.")

Keep up to date on testing

Stay abreast of current information on HSV-2 testing, advises Warren, who is the author of The Good News About the Bad News (New Harbinger Publications), a book designed to provide updated information to those who have been diagnosed with HSV-2 infection. Providers should be aware of low positive/false positive issues with serologic testing, says Warren. Only 50% of people who test in the 1.1 to 3.5 range are infected, she notes.

"I spend a ton of time these days ordering Western blots [which detects the IgG blood antibody] for people around the country who test positive in this range," says Warren. "The same is true with IgM tests [which detects the IgM blood antibody], only even a high rate don't confirm."

When people find out they have herpes, they must be adequately informed about asymptomatic viral shedding, says Warren. Condom use, daily valacyclovir therapy, and disclosure of HSV-2 serostatus can cut the risk of HSV-2 transmission and help patients live successful lives, she notes.

Past research indicates that an unwillingness to discuss sexual issues can keep providers from offering important information on herpes, notes Wald.2 "People are uncomfortable talking about sexual issues, and that certainly has been documented in many different studies," says Wald. "You sort of have to 'go there' if you are going to be talking about genital herpes."


  1. Tronstein E, Johnston C, Huang ML, et al. Genital shedding of herpes simplex virus among symptomatic and asymptomatic persons with HSV-2 infection. JAMA 2011; 305:1,441-1,449.
  2. Gilbert LK, Schulz SL, Ebel C. Education and counseling for genital herpes: perspectives from patients. Herpes 2002; 9:78-82.