Two consecutive measles outbreaks with genotypes D8 and D4 in two mainly unvaccinated communities in Germany

A measles infection in a 13-year-old student from a free progressive school was the index case for an outbreak in Essen in 2010. In this type of school, mainly unvaccinated and measles-susceptible children accumulate. This observation is confirmed by the fact that some of the recent outbreaks originated in such institutions. In Essen, this outbreak was followed by a second smaller outbreak in unvaccinated children and adults in a low socio-economic setting and migration background. Measles were diagnosed clinically and/or were serologically confirmed. Genotyping of measles isolates was performed by PCR and sequencing. Vaccination certificates were checked by the Community Health Centre (CHC) of the City of Essen. Measures to prevent the spread of the infection were implemented and enforced according to the National Protection Against Infection Act (IfSG). In total, 86 cases of measles were notified from March to July 2010. Of all infected patients, 97 % had had no vaccination and 15 % had to be hospitalised. Clinical courses showed the severity of this infection. Epidemiologic evaluation and genotyping of measles virus (MV) detected in Essen revealed the presence of two distinct chains of MV transmission by genotypes D8 and D4 causing two independent outbreaks. The outbreaks were caused by the index cases, and the spread of infection was facilitated by insufficient vaccination coverage in certain groups. Immediate suspension of non-immune children from classes for 2 weeks might have limited the outbreak in the free progressive school. Overall, high measles vaccination coverage in children and adolescents in regular schools in Essen presumably prevented a greater spread of the virus.