
A lab image of herpes virus
I’m sure my boyfriend doesn’t have herpes, a patient recently told Dr. Lydia Shrier, an adolescent medicine specialist at Children’s Hospital Boston.
How could she be so sure? Dr. Shrier asked. Because, the patient replied, she had scoped out his body and “there’s nothing irregular about him.”
Dr. Shrier, a researcher on sexually transmitted infections, goes through this kind of conversation all the time. Patients tell her that they’ve never had blisters or lesions or sores, and so cannot possibly have genital herpes. The same for their sexual partners.
It falls to her to disabuse them of these notions, saying: “You can have lesions or not, you can have symptoms or not, you should basically be operating the same way, which is to assume that everyone has herpes.” That means taking precautions, from limiting sexual contact to using condoms.

Dr. Lydia Shrier
Though this is her longstanding message, she now has better evidence to back it up than ever before. Last week, a pre-eminent researcher on the genital herpes virus, known as Herpes Simplex Virus 2 or HSV-2, published a landmark paper documenting the striking rate at which people with no herpes symptoms can nonetheless “shed virus,” potentially infecting partners.
The study, led by Dr. Anna Wald of the University of Washington, found that people who’d had symptoms of herpes shed virus on about 20 percent of days, while people who test positive for herpes antibodies but have never had symptoms shed virus on only about 10 percent of days.
But here’s the kicker: When they’re shedding, people who’ve never had symptoms shed roughly the same amount of virus as people who’ve had symptoms. So it’s clearer than ever that lack of symptoms is no guarantee against infection. And in fact, Dr. Wald said, “Asymptomatic shedding may be the central phenomenon of transmission.”
In the old days, doctors would warn herpes patients to avoid sexual contact mainly when they had active lesions, believing that was the only time they were really contagious.
But evidence has long been growing that herpes can be transmitted even when no lesions are visible. The new study, by quantifying how much virus is shed even in the absence of symptoms, “is a real ‘aha!’ moment,” said Fred Wyand, spokesman for the American Social Health Association. “It’s really robust in terms of the number of subjects they enrolled and the length of time they were followed,” he said.
The study also helps explain how genital herpes has become so wildly common, infecting nearly one-fifth of the American adult population, given that it’s hard to imagine many people would want sex while they had the painful nether-regions equivalent of cold sores. Consider this stunning fact from the American Social Health Association:
In the United States, more people have genital herpes than all other sexually transmitted infections combined -– 50 million people in total.
There are more mind-boggling statistics. Continue reading →