Trends in prevalence of protective levels of hepatitis B surface antibody among adults aged 18-49 years with risk factors for hepatitis B virus infection-United States, 2003-2014.

Background. Hepatitis B virus (HBV) infection can be prevented through vaccination. However, previous data show that only about 24%-45% of US adults at high risk of HBV infection are protected. Our aims were to assess prevalence and trends in protective levels of hepatitis B surface antibody (anti-HBs) from 2003 to 2014 and explore factors associated with protection among adults at high risk. Methods. Data were taken from the 2003-2014 National Health and Nutrition Examination surveys. Our sample included adults aged 18-49 years who were tested for HBV and reported at least 1 of the following infection risks: history of sexually transmitted disease, sex with men (for men), infection with human immunodeficiency virus, and injection drug use. We calculated the prevalence of anti-HBs (>= 10 mIU/mL), indicative of immunity from vaccination, among respondents for three 4-year time intervals (2003-2006, 2007-2010, and 2011-2014) and applied the Cochran-Mantel-Haenszel test to assess trends. Using multivariable logistic regression, we examined factors associated with positive anti-HBs serology. Results. The prevalence of positive anti-HBs serology was 23.4%. Prevalence increased from 2003-2006 (16.3%) to 2007-2010 (27.3%), but no change occurred from 2007-2010 (27.3%) to 2011-2014 (28.1%). Among factors predicting positive anti-HBs serology were young age and higher education. Conclusions. By 2014, less than one-third of adults aged 18-49 years at risk of infection exhibited protective antibodies >= 10 mIU/mL. Because these adults account for a majority of unprotected adults, targeted intervention strategies are essential to achieve the hepatitis B elimination goal.