Background: Herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) are common infections with serious sequelae. HSV-1 is an increasingly important cause of genital herpes in industrialized countries.
Methods: Using nationally representative data from the National Health and Nutrition Examination Survey (NHANES), we examined HSV-1 and HSV-2 seroprevalence among 14- to 49-year-olds in the United States. We estimated seroprevalence in 1999–2004 and 2005–2010, stratified by sociodemographic characteristics and sexual behaviors. We also reviewed HSV-1 and HSV-2 seroprevalence from 1976–1980 to 2005–2010.
Results: In 2005–2010, the seroprevalence of HSV-1 was 53.9%, and the seroprevalence of HSV-2 was 15.7%. From 1999–2004 to 2005–2010, HSV-1 seroprevalence declined by nearly 7% (P < .01), but HSV-2 seroprevalence did not change significantly. The largest decline in HSV-1 seroprevalence from 1999–2004 to 2005–2010 was observed among adolescents aged 14–19 years, among whom seroprevalence declined by nearly 23%, from 39.0% to 30.1% (P < .01). In this age group, HSV-1 seroprevalence declined >29% from 1976–1980 to 2005–2010 (P < .01).
Conclusions: An increasing number of adolescents lack HSV-1 antibodies at sexual debut. In the absence of declines in HSV-2 infections, the prevalence of genital herpes may increase.
It appears that better hygeine, improvements in living conditions, and other factors have led to a decrease in the prevalence of HSV-1, which is a common cause of cold sores, in adolescents. That’s good! But there’s a problem. It’s thought that kids who get exposed to HSV-1 in a non-sexual way are better protected against genital herpes caused by HSV-1 later in life. Form the accompanying editorial:
Stated differently, almost 1 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. This is occurring at the same time in which sexual practices have substantially shifted, with increases in oral sex reported in adults over the past 20 years [5–7]. In 2007–2010, almost half of 15- to 19-year-olds and more than four-fifths of 20- to 24-year-olds had engaged in oral sex practices . This produces the perfect storm of serosusceptible adolescents engaging in sexual behavior that increases the likelihood that their first exposure to HSV-1 will be on their genitalia, and, thus, that they will develop HSV-1 genital herpes. Increasing rates of genital HSV-1 infection already are being seen in several studies published over the past decade [9–11], and Bradley and colleagues’ data give reason to be concerned that this trend will accelerate.
The “worst case” scenario would be an adolescent being exposed to genitally to HSV-1 by oral sex from another adolescent who has a cold sore. This would lead to an explosion of HSV-1 genital herpes. Since more adolescents are not building up immunity to HSV-1 today, and more adolescents are engaging in oral sex today, this is also a much more likely scenario today. It’s a problem.