Mumps in a boarding school: description of an outbreak and control measures

Background The number of cases of mumps in the UK has increased during 2004–2005. Understanding why some people are more susceptible to mumps infection will help target vaccination and other control measures in the future. This paper describes a mumps outbreak in a boarding school in Scotland (October to November 2004).

Objectives To describe the characteristics of cases in a mumps outbreak; and to conduct a case-control study looking at the effect of previous measles-mumps-rubella (MMR) vaccination.

Design Descriptive epidemiology.

Data sources Clinical, laboratory and surveillance data.

Setting A private school with 600 boarding and day pupils.

Results Fifty cases were notified to the public health department as having mumps. Twenty of the cases (40%) were confirmed virologically, all born between 1987–1991. A matched case-control study was conducted to explore the effect of prior MMR vaccination. Compared to no vaccine, MMR protected against mumps (odds ratio = 0.7), two doses offering best protection (odds ratio = 0.5), but the study was not large enough to detect a statistically significant difference.

Conclusion Some children and young people in the UK are currently incompletely vaccinated. This outbreak illustrates the potential of a mumps outbreak to disrupt the medical, educational and social life of a school. All children should be vaccinated with two doses of MMR vaccine before school entry. Children and young people born between 1979–1991 should be given the necessary additional dose(s) of MMR vaccine.