Trends in herpes simplex virus type 1 and type 2 seroprevalence in the United States
The seroprevalence of HSV-2 has declined, particularly in younger Americans.
What's known?
- HSV type 1 and 2 can cause either anogenital or oropharyngeal infection.
- HSV-1 has become an increasingly common cause of clinical anogenital herpes in developed countries.
- Pre-existing HSV-1 antibodies can alleviate clinical manifestations of subsequently acquired HSV-2.
What’s new?
- Cross-sectional, nationally representative surveys (US National Health and Nutrition Examination Surveys [NHANES], were used to compare national HSV seroprevalence estimates from 1999-2004 with those from 1988-1994.
- The analyses included 9165 persons from 1988-1994 survey and 11508 persons from 1999-2004 survey who were aged 14 to 49 years.
- The overall age-adjusted HSV-2 seroprevalence was 17.0% in 1999-2004 and 21.0% in 1988-1994, a relative decrease of 19.0% between the 2 surveys (95% CI, –28.6% to –9.5%; P<.001).
- The decrease in HSV-2 seroprevalence was concentrated in younger age groups.
- Overall decrease was greater in males (31.9%) than in females (19.4%).
- Among those infected with HSV-2, the percentage who reported having been diagnosed with genital herpes was statistically different (14.3% in 1999-2004 and 9.9% in 1988-1994; P = .02).
- Seroprevalence of HSV-1 decreased from 62.0 in 1988-1994 to 57.7% in 1999-2004, a relative decrease of 6.9% between the 2 surveys (95% CI, –11.6% to –2.3%; P = .006).
- Among persons infected with HSV-1 but not with HSV-2, a higher percentage reported having been diagnosed with genital herpes in 1999-2004 compared with 1988-1994 (1.8% vs 0.4%, respectively; P<.001).
- The authors have suggested that the reasons for significant decrease in HSV-2 seroprevalence even after accounting for changes in measured sexual behaviour may include factors such as careful partner selection, condom use and or choosing oral sex over vaginal sex.
- The changing HSV-1 seroprevalence may also have an impact on genital herpes as declines in HSV acquisition before onset of sexual activity will leave more individuals susceptible to genitally acquired HSV-1 infection when they become sexually active. Also, more individuals will acquire HSV-2 without HSV-1 antibodies. Confirmation of HSV type may contribute to optimal management of patients with symptomatic genital herpes.
