A High School Measles Outbreak ―Control Measures and Vaccine Efficacy

Epidemiological investigation of a March 2007 detected measles outbreak of 28 cases in a 792-student high school in Tokyo. Students with a vaccination history had significantly milder symptoms than those without, and no cases occurred among students having two of measles vaccine in two doses of measles vaccine in their childhood. Vaccine efficacy（VE）calculated in our investigation was 93.9％（95％CI : 87-97）, and no significant difference was observed in vaccine type or manufacturer product. Students and parents were extremely difficult to persuade to cooperate in control measures such as emergency vaccination and home isolation through notification letters even during outbreaks. Schools should thus develop measles outbreak preparedness and response plans and identify potentially susceptible students in advance through documented proof of case histories and MCV vaccination. Outbreaks should promote early detection of patients and emergency vaccination targetting potentially susceptible students backed through close cooperation with medical facilities, education institutions, and the public health sector,together with school closures as appropriate.