Today’s teens are more susceptible to genital herpes than teens a decade ago—but not for the reasons one might expect. Researchers say it's due to a decline in childhood exposure to herpes simplex virus (HSV) type 1, which causes cold sores and is a growing cause of genital herpes.
In the past, children were regularly exposed to the herpes virus through skin contact with an infected adult or by sharing lip balm or other personal items. This exposure can start the production of antibodies that can come in handy when teens become sexually active and may be exposed to herpes from a partner. But efforts to reduce HSV-1 exposure—by discouraging sharing cosmetics (along other tactics)—have translated to a 23 percent decrease in HSV-1 antibodies over the past ten years.
The decline in exposure can also be attributed in part to improved living conditions in industrialized nations, the researchers say.
These findings were reported in a new study published in The Journal of Infectious Diseases by researchers at the Centers for Disease Control and Prevention (CDC). The researchers used data from the National Health and Nutrition Examination Survey (NHANES), comparing teenagers between 2005 and 2010 with teenagers between 1999 and 2000.
“Almost one in 10 adolescents who 10 years ago already would have acquired HSV-1 earlier in life now are vulnerable to getting a primary infection as they enter their sexually active years,” writes David Kimberlin, M.D., the chair of infectious diseases at the University of Alabama at Birmingham School of Medicine, in an accompanying editorial.
Is Infection Protection?
It may sound counterintuitive, but childhood exposure to HSV-1 can have a protective effect against sexually transmitted herpes later in life, particularly once a person becomes sexually active, because antibodies can kick-start disease resistance.
“Declines in early childhood acquisition of HSV-1 means more young people are susceptible to genital HSV-1 infection, and symptomatic HSV-2 disease is more likely among persons lacking HSV-1 antibodies,” the authors write.
Symptoms, which present most commonly as lesions around the mouth and lips for HSV-1 and on the genitals for HSV-2, are episodic. A lifelong diagnosis may mean only occasional sores. HSV-1 infections are more commonly referred to as cold sores.
HSV-1 and 2 infections are often subclinical, meaning that people can test positive for the virus without ever showing symptoms. Unfortunately, both are lifelong diseases: once you’re infected, you’re infected for good. But the diagnosis may not be as dire as it sounds, and herpes is by no means a rare condition.
The CDC estimates that nearly 800,000 people are newly infected each year. Across the country, nearly one in six people between the ages of 14 and 49 test positive for HSV-2.
The Better Herpes?
HSV-1 is less likely to present as genital herpes in men and in pregnant women than HSV-2, Kimberlin writes. So HSV-1 might be considered the lesser of two evils.
While a decline in HSV-1 seroprevalence may leave teens more susceptible to HSV-2 infection when they become sexually active, it could lead to HSV-1 genital herpes later in life as well.
The group most seriously affected by the decline in early exposure, Kimberlin writes, may not be the infected teens, but rather infants born to mothers showing symptoms of genital herpes. Contact with lesions during delivery can lead to the transmission of herpes to the baby, which can lead to consequences as serious as death or lifelong neurological damage.
It’s hard to recommend greater exposure to herpes, but there are consequences to a decline in HSV-1 antibodies. Researchers recommend continued surveillance of HSV-1 and HSV-2 in teens.