Estimation of measles vaccination coverage and longer-term vaccine efficacy in a Queensland State High School during the 1993-94 measles epidemic

The parents of 470 students randomly selected from 1321 students attending a state high school were surveyed during the 1993-94 measles epidemic, by m eans of a take-home questionnaire. The response rate was 87%. Thirty stated that their child had measles during this epidemic; nine of these 30 gave a history of previous vaccination. Overall, 312 of the 470 (76%) stated that their child had been vaccinated, but only 34% indicated that they had vacc ination records. There were no measles cases during this epidemic in the gr oup with records. Those not vaccinated were at 10 times increased risk of c ontracting measles compared to those who had been vaccinated with or withou t records. Vaccine efficacy estimated in general a decade after vaccination based on parental recall of vaccination status regardless of whether they had vaccination records or not was 91% (95% CI 80%-96%). This calculation e xcluded 123 who claimed to have had measles prior to 1993 and 30 uncertain of their vaccination status.