Prevalence and factors associated with self-reported vaccination rates among US adults at high risk of vaccine-preventable hepatitis.

BACKGROUND: Despite a routine vaccination for preventing HAV and HBV in young age groups during the past decade, adults at high risk of hepatitis are not reached effectively by vaccination programs. This study sought to estimate the prevalence of adults at higher risk of vaccine-preventable hepatitis (hepatitis A virus (HAV) and hepatitis B virus (HBV)) in the US and their vaccination rates. Also, the association between vaccination rates and selected demographic, socio-economic characteristics and comorbidities was investigated.

METHODS: Four years, 1999-2002, of publicly available National Health and Nutrition Examination Survey (NHANES) data were utilized. Survey participants aged 20-59 years were selected. A survey participant was considered at higher risk when their situation and/or behavior placed them at a greater risk of contracting hepatitis as identified by the Centers for Disease Control and Prevention. All prevalence estimates were weighted to represent the total US population using 4-year interview and examination weights. Logistic regression was utilized to identify factors associated with vaccination rates.

RESULTS: The study included 6237 survey participants who represent over 153 million adults age 20-59 years. Of these adults, 8.0%, 12.3% and 1.4% were at higher risk of HAV, HBV or both respectively. The self-reported vaccination rates among the higher risk population groups were 13%, 23.6% and 13.4% respectively. The most prevalent risk groups were persons with sexually transmitted diseases and persons using noninjection illegal drugs. Within the higher risk population, being single, male, aged 50-59 years and uninsured were all significantly (p < 0.05) less likely to be vaccinated than their counterparts.

LIMITATIONS: The results of this study should be interpreted within the context of the following limitations: (1) the potential biases associated with participants' self-reported vaccination rates; (2) institutionalized US population with high prevalence rates of hepatitis infection are not included in the NHANES data.

CONCLUSIONS: Among the population identified at higher risk of vaccine-preventable hepatitis (HAV, HBV or both), only a small proportion of this group had evidence of hepatitis vaccination.