Epidemiology

Many at-risk adults not being vaccinated against hepatitis B

Last Updated: 2006-05-11 16:10:22 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Fewer than half of US adults considered to be at high risk for contracting hepatitis B virus (HBV) have been vaccinated against the virus, according to a report by investigators at the Centers for Disease Control and Prevention. Overall, only about one third of adults have received the vaccine.

The incidence of acute HBV infections fell from 8.5 to 2.1 per 100,000 population between 1990 and 2004, due primarily to high vaccination rates among children and adolescents. Of the estimated 60,000 new infections in 2004, 95% occurred among adults, Dr. C. Weinbaum and colleagues note in their paper, published in the Morbidity and Mortality Weekly Report for May 12.

These findings are based on results of the 2004 National Health Interview Survey of adults between the ages of 18 and 49 years. Among the 17,249 individuals surveyed, 5.7% were deemed to be at high risk, primarily because of unsafe sex or injection drug use.

Vaccine coverage in 2004 according to age was highest -- 48.1% -- among individuals age 18 to 20, and lowest -- 25.6% -- among those 41 to 49 years old. The highest proportion of vaccinees was health-care workers (80.5%) and police or firefighters (63.6%).

In a multivariate model, high risk was a statistically significant predictor of HBV vaccination (45%, adjusted odds ratio 1.3 compared with those not at high risk). In contrast, HBV vaccine coverage is 92% among children and 86% among adolescents.

The authors blame the low vaccination rates on the lack of national programs to purchase vaccine, and lack of infrastructure for vaccine administration to adults.

"To increase coverage," Dr. Weinbaum's group writes, "public health programs and primary care providers should inform adults ... of the potential benefits of HBV vaccination, ... and adopt strategies appropriate for practice setting to ensure that all adults at risk for HBV infection are offered HBV vaccine."

In a separate article in the MMWR, Dr. H. Pollack, at New York University School of Medicine, and associates screened immigrants from Asian and western Pacific countries, where HBV is endemic. The program, which provides free vaccination and treatment in this population, screened 1633 persons in early 2005, 24% of whom had chronic HBV infection. This prevalence rate is approximately 35 times that of the overall US population.

Approximately half of those tested had evidence of resolved HBV infection -- a positive result for antibodies against HBV and a negative result for HBV surface antigen.

Dr. Pollack's group recommends screening programs for Asian and Pacific Islanders to identify and treat patients with chronic infection and to vaccinate their contacts who have not yet acquired HBV infection.

Mor Mortal Wkly Rep CDC Surveill Summ 2006;55:506-511.