Decline in Hepatitis E Virus Antibody Prevalence in the United States From 1988-1994 to 2009-2010

Background. Previous population-based estimates in the United States have shown a relatively high prevalence of hepatitis E virus (HEV) antibody. We sought to determine whether changes in the prevalence of HEV antibody have occurred over time. Methods. We analyzed data from the 2009-2010 National Health and Nutrition Examination Survey (NHANES) and NHANES III (1988-1994). Using the same serologic assay, we compared the estimated anti-HEV immunoglobulin G (IgG) prevalence and risk factors for antibody positivity for the 2 periods. Results. The prevalence of HEV antibody among those aged >= 6 years declined from 10.2% (95% confidence interval [CI], 9.1%-11.4%) during 1988-1994 to 6.0% (5.2%-6.8%) during 2009-2010, and the prevalence for those of US birth ranged from 9.6% (8.4%-10.9%) to 5.2% (4.4%-6.2%). Among US-born persons, the estimated HEV antibody prevalence declined significantly for all subgroups of age, sex, region of residence, and number of persons per room in the household; significant declines also were observed for persons at or above poverty level and for persons of non-Hispanic white, non-Hispanic black, and Mexican American race/ethnicity. No clear associations with food consumption were found. Conclusions. The anti-HEV prevalence is declining in the United States. Although the decline suggests a decrease in exposure to HEV over time, the risks associated with exposure remain unknown.