Background: Herpes simplex virus type 2 (HSV-2), the agent causing one of the most common sexually transmitted infections in sexually active individuals, is currently considered a public health problem. In Mexico, there have been no population-based studies of the prevalence and factors associated with HSV-2 infection among young students.
Goal: The goal was to measure HSV-2 seroprevalence and identify possible associated factors among students in the state of Morelos, Mexico.
Study design: Through a cross-sectional population-based study involving students at 92 schools in the state of Morelos, Mexico, 898 students aged 11 to 24 years old were identified. All of them reported they had already initiated sexual activity and provided a blood sample to detect the presence of anti-HSV-2 antibodies through the Western blot technique. The association between risk factors and HSV-2 was evaluated through multiple logistic regression analysis with stratification by sex and schooling level.
Results: In the population under study, the prevalence of HSV-2 seropositivity was 5.7% (51/898), and the ratio of females to males was 2:1. The prevalence of consistent condom use overall was 22.6% among the 898 students. For students in Morelos State, Mexico, the HSV-2 seroprevalence was higher among the youngest female students (9.5% among junior high school versus 3.3% among university students; P<0.001). The main factors associated with HSV-2 infection were sex (for females the risk was 2.2 times higher than for males; 95% CI, 1.2-3.9); junior high school status (2.5 times higher risk than university students (95% CI, 1.1-6.0); and having had same-sex sexual intercourse (3.5 times higher risk; 95% CI, 1.4-8.9).
Conclusion: In contrast with other reports, the HSV-2 seroprevalence was higher among younger people. This finding can be explained by a cohort effect of more exposition to behavioral risks, particularly an earlier age at first intercourse and very low use of condoms among youngest students. Longitudinal surveys about serological responses to HSV-2 infection in different age groups are warranted.