Learning Objectives for this Presentation:
By the end of the presentation participants will be able to describe changes in hepatitis B vaccine coverage and acute hepatitis B incidence among adolescents.

Background:
Vaccination of adolescents has been recommended since 1996. In 1999, California required hepatitis B vaccination for seventh grade entry. Although school vaccination requirements have been shown to rapidly and substantially increase hepatitis B vaccine coverage, their effect on acute hepatitis B incidence among adolescents is less clear.

Objectives:
To examine trends in hepatitis B vaccine coverage and acute hepatitis B incidence among adolescents, following implementation of a seventh grade school entry requirement in California.

Methods:
Yearly trends of hepatitis B vaccine coverage and acute hepatitis B incidence among adolescents were analyzed using school vaccination coverage and disease surveillance data reported between 1999 and 2004. Incidence rates were calculated using demographic information from the California Department of Finance.

Results:
In 1999, the first school year of the seventh grade school entry requirement, 68.6% of students completed the hepatitis B series at school entry. By 2003, the last school year of seventh grade hepatitis B vaccine coverage data, the proportion of students completing the hepatitis B series had increased to 81.6%. Between 1999 and 2004, the incidence of reported acute hepatitis B among adolescents 12-18 years old decreased from 1.5 cases per 100,000 to 0.1 cases per 100,000, representing a decline of 93.3%. Between 2002 and 2004, all but one reported case occurred in 16-18 year olds.

Conclusions:
Following implementation of a seventh grade school entry requirement, the increase in hepatitis B vaccine coverage was substantial and acute hepatitis B incidence declined rapidly among vaccinated adolescents. The observed decline in disease incidence occurred more slowly in the older adolescents who were not immediately affected by the seventh grade school entry requirement.