Age at and time since vaccination during a measles outbreak in a rural community

During winter 1978, 350 cases of measles were reported in Livingston County, Michigan, a small, rural county. Of these cases, 250 occurred in the school-aged population. A search of school records and contact with parents provided complete vaccination data on 5,973 students. Attack rates in children vaccinated at the age of 12 months or younger were more than twice the rates of those vaccinated at older ages. Time since vaccination was not a statistically significant predictor using multiple logistic analysis.