BACKGROUND:
Vaccination of adolescents remains a major challenge to our health care system. In spite of efforts to establish routine visits for preventive care, adolescent immunization coverage has risen slowly. School immunization requirements and voluntary programs have been used to increase coverage.

OBJECTIVE:
In two cities across two states, we compared the extent to which a middle school hepatitis B immunization law (law) and voluntary school-based hepatitis B immunization program (program):
1. increased immunization rates for hepatitis B,
2. increased immunization rates of other recommended vaccines, and
3. reduced racial and economic disparities in immunization rates.

METHOD:
A retrospective design with purposive sampling, using location of residence to determine study group, was used. School immunization records from a random sample of up to 75 students in 9th, 11th, and 12th grades from 19 schools in three areas discordant for immunization laws and/or voluntary programs were analyzed.

RESULT:
Of the 3484 student records reviewed, 99.6% had an immunization record. In the sites with the law, 55% of students were up-to-date for hepB; without the law the rate was 28%. Immunization rates for MMR#2, required at all sites, were similar. Rates for Td were higher at the sites with the law. Immunization rates in schools with a high percentage of students on free/reduced lunches and/or minority students were significantly lower than other schools, regardless of law. Without the law, hepB rates were higher in schools that previously participated in a voluntary program.

CONCLUSION:
Middle school immunization laws are effective at raising adolescent immunization rates. The effects of a hepatitis B law on rates of other recommended vaccines were mixed. Economic disparities continue into adolescence and were not influenced by immunization laws. School-based programs were also effective.

LEARNING OBJECTIVES:
Understand the influence of middle school immunization laws and voluntary school-based programs on adolescent immunization rates.