The number of hepatitis B cases among children and adolescents has declined by 89 percent since 1991, according to a new federal report.

The CDC study shows that the number of hepatitis B cases reported among children and teens aged 19 and under has dropped from about three per 100,000 in 1990 to 0.34 per 100,000 in 2002.

Researchers credit the decline with the recent introduction of widespread vaccination against hepatitis B among children and infants.

In 1991, universal infant hepatitis B vaccination was implemented in the U.S. In 1995, these recommendations were expanded to include routine vaccination of children aged 11-12. In 1999, they included all children under age 18 who had not been vaccinated previously.

Hepatitis B Cases Falling

In the study, researchers analyzed confirmed cases of hepatitis B in children reported from 1990 to 2002.

They found the rate of hepatitis B in children and adolescents declined by 89% during this time period.

The study also showed that racial disparities in hepatitis B rates are decreasing. In 1990, hepatitis B rates were highest among Asians/Pacific Islanders with about seven cases per 100,000 and among blacks with about four per 100,000. Whites had the lowest rate with about one case per 100,000.

By 2002, the number of hepatitis cases per 100,000 had dropped to 0.55 among Asians/Pacific Islanders, 0.51 among blacks, and 0.16 among whites.

Researchers say many of the hepatitis cases in people born after 1990 were among international adoptees and other children born outside of the U.S. International adoptees are exempt from U.S. hepatitis B vaccination regulations.

By Jennifer Warner, reviewed by Brunilda Nazario, MD

SOURCES: Morbidity and Mortality Weekly Report, Nov. 5, 2004; vol 53: pp 1015-1018. News release, CDC.