Measles vaccine efficacy study in a Canberra high school: a study following a measles outbreak.

An outbreak of measles which occurred in Canberra between October and December, 1991, was investigated to estimate the public health utility of the vaccine. The measles vaccine efficacy was determined for the 13-15 year old children in a selected high school. During the outbreak, at least 82 Canberra children contracted measles. Teenage males accounted for 56% of total cases, and 22% of cases were confirmed by serology. The vaccine coverage in the high school studied decreased with increasing school years, varying from 85.8% in Grade 8 to 79.2% in Grade 10. The highest attack rate occurred in Grade 10 (66/1000). The vaccine efficacy for age 13-15 was estimated to be 72% (95% Cl, 45-86%) but varied from 67 to 73%. Measles remains a serious disease of childhood in Australia. The elimination of measles is only partly dependent on the vaccine coverage of children. Issues relating to the effectiveness of vaccine are also important. A two dose vaccine strategy with the second dose of measles, mumps, rubella vaccine (MMR), given preferably in the last year of primary school or the first year of high school, is supported by the findings of this study.