Herpes largely undiagnosed
■ Some 80% of Americans who test positive for simplex virus type 2 do not know they're infected, a CDC study finds.
By Christine S. Moyer — Posted May 18, 2010
Health experts recommend that physicians boost efforts to educate patients about herpes simplex virus type 2 and test more for it, after a study showed that the infection is widely prevalent in the U.S. and largely undiagnosed.
A Centers for Disease Control and Prevention study found that about one in six Americans age 14 to 49 is infected with HSV-2. Of those who tested positive for the virus, more than 80% did not know they were infected, according to findings published April 23 in the CDC's Morbidity and Mortality Weekly Report.
Internist Georges Benjamin, MD, said more should be done to prevent and reduce the transmission of sexually transmitted diseases. He and other health professionals hope the report will bolster support for developing an HSV-2 vaccine.
"We've made some inroads to be more open and to talk about STDs. But as a nation, we still have a long way to go," said Dr. Benjamin, executive director of the American Public Health Assn.
He recommends that health professionals educate patients on how to prevent HSV-2 and discuss its medical complications, which include an increased risk for HIV. He also urges physicians to test all patients who have symptoms of the virus.
For its report, the CDC analyzed serologic test results from 7,293 people, age 14 to 49, who participated in the National Health and Nutrition Examination Survey between 2005 and 2008 (link).
Researchers found that 16.2% tested positive for HSV-2 antibodies. Prevalence of the virus has remained relatively stable since the CDC's last national estimate of 17% for 1999-2004.
Researchers found that blacks and women were most likely to be infected. Prevalence of the virus was nearly twice as high among women (20.9%) than men (11.5%). Infection rates were more than three times higher among blacks (39.2%) than whites (12.3%). Black women had the highest prevalence rate (48%).
The rate of infection increased with age. The virus was detected in 1.4% of 14- to 19-year-olds. The figure was 26.1% among 40- to 49-year-olds.
Diagnosing the virus
"The implication [of the study's findings] to the medical field is that we need to do better," said Roy Gulick, MD, MPH, professor of medicine and chief of the division of infectious diseases at New York-Presbyterian Hospital/Weill Cornell Medical Center.
The CDC report highlights a need to identify people infected with HSV-2. But the challenge in diagnosing it is that it's often asymptomatic, Dr. Gulick said. Complicating matters, the virus can be transmitted sexually even when symptoms are not present.
Daily medication can reduce sexual transmission of the virus by about 50%, according to Scott Bryan, a spokesman with the CDC's National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention. People who use condoms consistently have a 30% decreased risk of acquiring HSV-2 compared with people who have unprotected sex, he said.
"Developing a vaccine is probably the only effective way of controlling genital herpes," said Larry Corey, MD, head of the infectious disease program at Fred Hutchinson Cancer Research Center in Seattle.
The CDC recommends screening for herpes in individuals who have symptoms, have an infected sexual partner, or are considered to be at higher risk of infection. The high-risk group includes people with multiple sexual partners.
Anyone who tests positive for a STD should be tested for all sexually transmitted diseases, including HIV, Dr. Gulick said.