School-based influenza immunization.

Annual influenza vaccination of schoolchildren will protect individual vaccines and, with high coverage, may protect entire communities. Because schoolchildren are more difficult to reach than preschoolers, school-based immunization programs may be needed to reach a high percentage of children. We offered free live, attenuated influenza vaccine to all healthy schoolchildren (K-12) in three Minnesota counties. Counties vaccinated from 33% to 58% of students. Overall, 41% of enrolled children were vaccinated. Elementary students were vaccinated at higher rates than older students. Administrative costs averaged $9.78 per dose delivered. School-based immunization programs offer the potential to achieve higher vaccination coverage of schoolchildren at modest cost.