KEYWORD1:
Hepatitis B, Incidence, Surveillance

BACKGROUND:
The epidemiology of acute hepatitis B has changed dramatically since California initiated a comprehensive immunization strategy to eliminate hepatitis B virus (HBV) transmission in 1991.

OBJECTIVE:
To describe the epidemiology of acute hepatitis B in California from 1990-2002.

METHOD:
All cases of acute hepatitis B reported to the State Notifiable Diseases Surveillance System between January 1990 and October 8, 2002 were analyzed. Perinatal case counts were obtained from the Perinatal Hepatitis B Prevention Program. Incidence rates were calculated using 1990/2000 U.S. census data and intercensal population estimates.

RESULT:
From 1990-2001, the incidence of acute hepatitis B declined from 9.8 to 2.4 cases per 100,000 population. Among children under 19 years of age, incidence declined 92% (from 2.7 to 0.2 per 100,000), while among persons aged 19 and older, incidence declined 73% (from 12.4 to 3.3 per 100,000).
As of October 8, 2002, 450 cases (annualized rate of 1.3 per 100,000) of acute hepatitis B have been reported this year. Nine cases (2%) were reported among children ages 16-18. No acute cases were reported in children under the age of 16. However, 26 cases of perinatal hepatitis B have been reported in California this year. It is unknown if any of these infants were acutely infected with HBV at the time of diagnosis.

CONCLUSION:
Since the initiation of a comprehensive immunization strategy in California the incidence of acute hepatitis B has dramatically declined. Although acute HBV appears to have been nearly eliminated among children 2 to 16 years of age, continued efforts are needed for the complete elimination of perinatal HBV and acute infection in young adults.
LEARNINGOBJECTIVES:
Describe changes in hepatitis B epidemiology in California from 1990-2002.