Outbreak of Measles among School Ages in Yeongju in 2000

Cheong, Hae Kwan; Bae, Geun Ryang; Jeong, Jin Hwa; Park, Sue Kyung; Park, Byung Chan; Kim, Jee Hee; Lee, Joo Yeon; Na, Byung Kuk; Kim, Woo Joo

Abstract

BACKGROUND
The outbreak of measles from 2000 to 2001 was the biggest epidemic since measles vaccination was introduced in Korea. Outbreak of measles in Yeongju was one of the earliest milestones of the nationwide outbreak in the year 2000. The authors investigated epidemiologic characteristics of the outbreak in this area.
METHODS
The authors estimated attack rate through the investigation of all the school age cases of measles reported to local health authority between March and May, 2000. Case investigation was done to trace the source of the outbreak. One hundred seventy two cases were examined with medical examination, with interview on their clinical manifestations, and with serologic examination on the anti-measles IgM and IgG antibody.
RESULTS
Overall attack rate among the school children was 4.3%, with highest attack rate in middle school students (8.5%). The outbreak began in March in middle schools, which spread to elementary and high schools. IgG was positive in 160(93.0%) cases and IgM was positive in 94(54.6%) cases, among which 90 cases (95.7%) were also positive for IgG. IgM positive cases had higher prevalence of rash (91.5%) compared to those without IgM (70.5%). Diagnostic criteria based on the clinical manifestation and contact history showed the highest sensitivity (92.6%) compared to conventional diagnostic criteria in outbreak (40.4-44.7%)
CONCLUSIONS
High proportion of susceptible children in the population due to primary or secondary vaccine failure played a key role in this outbreak. Clinical manifestation was milder than classical measles and adjustment of diagnostic criteria can be helpful in the management of outbreak.