Mumps outbreak in young adults following a festival in Austria, 2006.

Mumps is not a mandatorily notifiable disease in Austria. However, in the first week of May 2006, a sudden increase in serologically confirmed cases of mumps, confined to three public health districts of the southern Austrian province of Carinthia, was identified by the Austrian Reference laboratory for MMR. An epidemiological investigation of this cluster of mumps cases was performed. A total of 214 cases fulfilled the outbreak case definition; 143 cases were laboratory confirmed and 71 cases were epidemiologically linked and fulfilled the clinical picture of the case definition. The vaccination status was known for 169 patients. Nearly half of the cases for whom the vaccination status was known occurred in non-vaccinated persons, another 40% were vaccinated with one dose of the vaccine and 11% had received two doses. Only four mumps cases occurred in children aged 14 years or younger, indicating that the vaccination coverage and the acceptance of the recommended childhood vaccinations have strongly improved within the past 15 years. Vaccination scheme failure but not vaccine failure is primarily to blame for this mumps outbreak.