The epidemiology of mumps in southern Alberta 1980-1982.

The full spectrum of mumps in Southern Alberta was studied over the years 1980-1982. In the community, a random sample of 3,497 children was tested for prevalence of immunity to mumps. The 1,816 who were not immune were retested after one year. The incidence of new immunity was 16.5%. Most seroconverters had no illness suggestive of mumps. History of previous mumps or immunization were found to be unreliable predictors of serologic immune status. In the family study, information was obtained on 342 cases diagnosed as mumps by family physician recorders. The overall complication rate was 10.8% and the secondary attack rate within families was 11.7%. Hospital records of all 25 patients admitted in Calgary with mumps during the same period were analyzed. Estimated costs of unopposed mumps over 20 years compared with the estimated costs of vaccination showed that a vaccination program could give a benefit-cost ratio between 6.4 and 247. These studies show that mumps is a mild disease with relatively few serious complications or sequelae. Even so, there would be definite medical and economic benefit with immunization. A low-cost addition of mumps vaccine to the immunization program would be justified.