Epidemiology of Herpes simplex virus type 1 and Helicobacter pylori infection and coinfection

This study had two main goals: (1) to determine the prevalence of and identify explanatory variables for Herpes Simplex virus type 1 (HSV-1) seropositivity in a nationally representative sample of the United States and (2) to quantify the association between HSV-1 and Helicobacter pylori (HPP), a bacterium that may also infect and/or coinfect the gastrointestinal tract. We analyzed cross-sectional data from individuals examined during the first phase of the Third National Health and Nutrition Examination Survey (NHANES III) conducted in 1988--1991 by the National Center for Health Statistics. Data were collected through standardized questionnaires, laboratory tests and physical examinations. We analyzed seropositivity in relation to age, gender, race/ethnicity, poverty income ratio, marital status, education, household size, urban or rural residence, place of birth, frequency of dental appointments, history of orthodontic treatment, alcohol or tobacco history, and history of military service. Prevalences and prevalence ratios (PRs) with 95% confidence intervals (95% CI) were obtained using Generalized Estimating Equations and SUDAAN to account for the NHANES III complex sample design.Crude overall prevalence of HSV-1 seropositivity in individuals aged 12--49 years was 60% (95% CI: 57--63). Seropositivity was associated with older age, female gender, lower education, poverty, being non-white or Mexican American, having been born outside the U.S., having ever been married or currently cohabiting, having no history of orthodontic treatment, and not receiving routine dental care. The crude overall PR (95% CI) for HPP seropositivity was 2.20 (1.69--2.85) comparing HSV-1 positive versus negative individuals. In large, urban households the HPP PR (2.27) was twice that in small, rural households (1.15), after adjustment for race/ethnicity and poverty level.HSV-1 is highly prevalent in the U.S. population. The results of this study can be used to prioritize resources and target populations at high risk that may most benefit from future interventions, such as novel prophylactic vaccines. HPP seropositivity is not consistently associated with HSV-1 seroprevalence, suggesting that external environmental factors rather than biological reasons may be mostly responsible for the association between these two organisms.