About 5.1 percent of the American population had been exposed to HBV (hepatitis B virus) between 1988 and 1994, writes George Ioannou, BMBCh, MS, of the University of Washington, and the author of the Annals article. Since that time frame, extensive vaccination campaigns for children, as well as education about safe practices, should have led to a drop in HBV infection rates.
A group headed by Ioannou carried out a national survey to explore HBV immunity rates in the United States between 1999 and 2008. The analysis involved nearly 40,000 people ages 2 and older enrolled in the National Health and Nutrition Examination Survey.
The researchers found that HBV exposure among individuals ages 18 or younger was extremely low, an indication of effective vaccination programs among the young. In fact, very high rates of immunity to HBV were documented between 1999 and 2008 among 2-year-olds: More than 68 percent had vaccine-induced antibodies to the virus.
Adults, including those at high risk for infection, had much lower rates of immunity.
In conclusion, the author noted, large numbers of children and adolescents are growing up in the United States with high rates of immunity against HBV and very low rates of infection. Future vaccination efforts, he added, should target at-risk adults.