Ongoing outbreak of mumps infection in Oban, Scotland, November 2010 to January 2011.

We report on an ongoing outbreak of 119 cases of mumps virus infection in the Oban area of Scotland, from 29 November 2010 to 31 January 2011. The median age of cases was 20 years, with the highest incidence in the 13-19-year-olds. A total of 53 cases had received two doses of measles-mumps-rubella (MMR) vaccine, in accordance with the United Kingdom vaccination schedule, while 33 had received only one dose and 30 had not been vaccinated.