Hepatitis E seroprevalence in the United States: Results for immunoglobulins IGG and IGM

Previous research identified a decline in hepatitis E virus (HEV) seroprevalence in US in 1988-1994 and 2009-2010. We investigated most recent HEV epidemiology.

Using a nationally representative sample (7656 persons in the National Health and Nutrition Examination Survey [NHANES] 2013-2014 and 7124 persons in NHANES 2015-2016), we compared the weighted seroprevalence of HEV (immunoglobulin G [IgG]/immunoglobulin M [IgM]) among people from the US (aged ≧ 6 years) between these two time periods. Sampling-weighted multivariate logistic regression models were used to identify factors associated with HEV seropositivity.

The median participant age was 37 years (interquartile range = 17-58 years); 51.17% of them were female. Among US-born individuals, HEV seropositivity (IgG/IgM) increased from 4.5% (95% confidence interval [CI] = 3.5%-5.5%) in 2013-2014 to 8.1% (95%CI = 6.5%-9.7%) in 2015-2016. Recent HEV infection (IgM) has nearly doubled in all US-born people. For participants born in and outside of the US, the overall weighted HEV (IgG/IgM) seropositivity increased from 5% (95%CI = 3.9%-6.1%) during 2013-2014 to 7.7% (95%CI = 7.2%-10.5%) during 2015-2016. In "non-Hispanic Asian" females, HEV seropositivity (IgG/IgM) rose from 8.4% (95%CI = 5.6%-11.1%) during 2013-2014 to 20.7% (95%CI = 15.8%-25.7%) during 2015-2016. In "non-Hispanic Asian" males, HEV seropositivity (IgG/IgM) increased from 9.3% (95%CI = 6.9%-11.8%) during 2013-2014 to 16.8% (95%CI = 12.5%-21.2%) during 2015-2016. HEV (IgG/IgM) seropositivity was significantly associated with "non-Hispanic Asian" ethnicity (odds ratio [OR] = 1.69; CI = 1.12-2.56), female (OR = 1.2, CI = 1.06-1.38), and age (OR = 1.058, CI = 1.05-1.06). No clear etiologic agent was found.

The combined and strata-specific HEV weighted seroprevalence increased from 2013-2014 to 2015-2016. Although prior studies had found increasing age as the only significant factor associated with HEV, the attribute of "non-Hispanic Asian" had a stronger association with HEV seropositivity than the age factor alone.