Correlates of Hepatitis A in the United States Population Under 20 Years of Age

Objective: Describe hepatitis A occurrence in the United States population under 20 years of age using a nationally representative sample and assess selected demographic and environmental correlates of Hepatitis A antibody (HAA) status. Methods: Analyses of the Cross sectional 2007-2008 US National Health and Nutrition Examination Survey (NHANES) data among respondents less than 20 years of age was conducted by describing HAA status as it relates to demographic, socioeconomic, and environmental factors. HAA status correlates were assessed using multivariate logistic regression to obtain odds ratios with 95% confidence intervals, accounting for survey weights and cluster sampling. Results: A total of 2041 subjects were available for multivariate analyses. The mean (SD) age of the population was 9.5 (7.0) years. Fifty-two percent were males and 48% females. Fifteen percent were Mexican Americans, 62% were White, 16.7% were Black, and 7% were other Hispanics. Thirty-nine percent were positive to HAA and almost 50% did not receive vaccination for hepatitis A. Among ethnic groups, Mexican Americans had the highest percentage of antibody positivity (75%) compared to Whites (28%), Blacks (36.8%) and other Hispanics (48.7%). Also, Mexican Americans and Other Hispanics were more likely to receive at least one dose of hepatitis A vaccination (73% each) compared to Whites (43%). Multivariate analyses showed that Mexican Americans have significantly greater odds for testing positive to the HAA than Other Hispanics (0R 0.29, 95% CI 0.14, 0.60), Whites (OR 0.18, 95% CI 0.089, 0.36) and Blacks (0R 0.21, 95% CI 0.10, 0.44, after adjusting for vaccination status, age, gender, family income to poverty ratio and water source. Younger age was negatively associated with increased HAA positivity (OR 0.95, 95% CI 0.92, 0.98). As expected, subjects who had received one dose (OR 3.15, 95% CI 2.15, 4.61) or two doses (OR 4.8, 95% CI 1.55, 15.1) of hepatitis vaccine A had greater odds of having HAA than those receiving no dose. Finally, the family income to poverty ratio was positively associated with HAA status. When restricted to non-vaccinated subjects, Mexican American ethnicity still had greater odds of HAA positivity, signaling past infection. Discussion: Results show that Mexican Americans have the highest percentage of positivity to HAA acquired through infection and vaccination; other ethnic groups are less likely to be positive to this antibody, even after adjusting for vaccination rates and socioeconomic variables. Prevention efforts should be strengthened for Mexican Americans in the US.