Determinants of Hepatitis B Vaccination Among Adults in the United States: NHANES 1999-2006

Background: In the United States, approximately 1.3 million people live with chronic hepatitis B virus (HBV). Among adults, HBV transmission occurs principally among unvaccinated adults with risk behaviors for HBV transmission and horizontal transmission.

Objectives: To estimate the prevalence of vaccination and HBV infection status of adults and to evaluate the trend in self reported vaccination and seroprevalence for Hepatitis B for this population; to assess the association between vaccination rates, seroprevalence, demographic, and socioeconomic characteristics.

Methods: Eight years, 1999-2006, of the National Health and Nutrition Examination Survey (NHANES) data were used. The vaccination status was identified through self-report and serologic markers. The association between potential predictors of vaccination and vaccination status was assessed using bivariate analysis. We used logistic regression model to obtain odds ratios and their 95% confidence intervals for the association between predictor variables and vaccination status.

Results: Unvaccinated adults were more likely to be male, over the age of 40, Non-Hispanic white, born in the US, married, have some education beyond high school, have a household income greater than $20,000, live in a smaller household, have health insurance coverage, and a source of usual care. High risk adults comprised about 16% of adults who had received at least one dose of the Hepatitis B vaccine. Almost half of the adults who reported receiving all three doses of the vaccine tested negative for immunity. For all adults the prevalence increased from 23.4% to 39.1%. Compared to adults in 1999-2000, adults were twice as likely to report vaccination in 2005-2006.

Conclusions: Only 32% of high risk adults are vaccinated. The rise in vaccination rates in young adults is mostly related to childhood immunization strategies and not strategies aimed at adults. More targeted interventions are needed to educate and vaccinate the adult population and to create a means for identifying those at risk and those already vaccinated.