Measles outbreak spreading from the community to an anthroposophic school, Berlin, 2011

Between April and July 2011 there was an outbreak of measles virus, genotype D4, in Berlin, Germany.We identified 73 case-patients from the community and among students of an anthroposophic school, who participated in a 4-day school trip, as well as their family and friends.Overall, 27% were aged >= 20 years, 57% were female and 15% were hospitalized.Of 39 community case-patients, 38% were aged >= 20 years, 67% were female and 63% required hospitalization.Unvaccinated students returning from the school trip were excluded from school, limiting transmission.Within the group of 55 school-trip participants, including 20 measles case-patients, a measles vaccine effectiveness of 97.1% (95% confidence interval 83.4-100) for two doses was estimated using exact Poisson regression.Our findings support school exclusions and the recommendation of one-dose catch-up vaccination for everyone born after 1970 with incomplete or unknown vaccination status, in addition to the two-dose routine childhood immunization recommendation.