HSV-1 affected 57.7% of Americans tested in a 1999-2004 study.
The most recent data for HSV-2 was published in March 2010, based on a National Health and Nutrition Examination Survey study performed between 2005 and 2008 by CDC. About 1 in 6 Americans (16.2%) aged 14 to 49 is infected with HSV-2. HSV-2 prevalence was nearly twice as high among women (20.9%) than men (11.5%), and was more than three times higher among blacks (39.2%) than whites (12.3%). The most affected group was black women, with a prevalence rate of 48%. Prevalence increased with age and number of partners. Only 18.9% of those infected had previously been aware of their infection.
African Americans and immigrants from developing countries typically have an HSV-1 seroprevalance in their adolescent population that is two or three times higher than that of Caucasian Americans. Many white Americans become sexually active while seronegative for HSV-1. The absence of antibodies from a prior oral HSV-1 infection leaves these individuals susceptible to herpes whitlow, herpes gladiatorium, and HSV-1 genital infection. Primary genital infection brings with it the risk of vertical transmission to the neonate, and is highest if the mother contracts a primary infection during the third trimester of pregnancy. In the U.S. the number of genital infections caused by HSV-1 is now thought to be about 50% of first episodes of genital infection.
In healthy adults, HSV-2 infection occurs more frequently in the USA than in Europe.
Seroprevalence rates in the USA appeared to be increasing, rising from 16.4% in 1976 to 21.8% in 1994. However, this trend seems to have reversed itself in recent years, dropping to 17.2% in 2004.
The current prevalence of genital herpes caused by HSV-2 in the U.S. is roughly one in four or five adults, with approximately 50 million people infected with genital herpes and an estimated 0.5 million new genital herpes infections occurring each year. African Americans appear more susceptible to HSV-2, although the presence of active genital symptoms is more likely in Caucasian Americans. The largest increase in HSV-2 acquisition during the past few years is in white adolescents. People with many lifetime sexual partners and those who are sexually active from a young age are also at higher-risk for the transmission of HSV-2 in the U.S.
Women are at higher risk than men for acquiring HSV-2 infection, and the chance of being infected increases with age. The CDC reports that 48% of African American women in the United States are infected with the HSV-2 virus.