Epidemiologic Study of Measles Outbreak in School-Aged Children in East KyongGi-Do Area

Yi, In Kyu; Choi, Jong Woon; Kim, Soon Ki; Son, Byong Kwan; Kim, Jeung Gyu; Yu, Seong Ki; Jo, Myung Cheol; Jang, Il Suk

Abstract

PURPOSE: There was marked decline of measles outbreak in the world since the first measles vaccine had been introduced. Recently, however, measles outbreak in the vaccinated children have been reported worldwide, which was ascribed to the possibilities of primary or secondary vaccine failure. We investigated the incidence in the school-aged children in the Kyong-gi Do area, the larger district which covers the urban and rural area, by the questionnaire.
METHODS
The questionnaires which were asked to the students' parents of 14 elementary schools in and nearest Sungnam city, Kyong-Gi Do for their present age, experience of measles attack and vaccination, and the age of measles attack. The answers of this questionnaire were analysed by SAS computer program.
RESULTS
1) Measles vaccination rate at 9 months was 70.5% and MMR vaccination rate at 15 months was 91.3%. 2) Measles attack rate among unvaccinated group was 53.8%, and 16.1% in vaccinated group. There was significant low risk of measles attack among vaccinated group than unvaccinated group(relative risk=3.35, p<0.001). 3) Vaccine efficacy of measles in this age group was 69%. 4) Age distribution of measles outbreak reveals bimodal pattern, the graph shows two peak incidence of 1 year-old and 6 years-old. 5) There were no significant differences of measles incidence in the different medical care service center that measles vaccination had been done.
CONCLUSIONS
Despite high rate of measles vaccine coverage in Sungnam, the attack rate of measles in the vaccinated population was relatively high. There may be due to primary, secondary vaccine failure or the other factors. The policy of measles vaccination in Korea should be reestablished as soon as possible.