Epidemiological Study of Rubella Outbreak in Chungchungnam-Do in Middle and High School Students in a Local Small Town

Cheong, Yoo Seock; Won, Young Ill; Yoo, Sun Mi; Park, Eal Whan; Lee, Chang Suk

Abstract

BACKGROUND: Rubella is a viral infection of childhood. Its clinical manifestations are not serious, but rubella infection in early pregnancy can result. in congenital rubella syndrome. In Korea, there have been several rubella outbreaks in 1996. We performed an epidemiological study about a rubella outbreak in middle and high school students in an isolated small town.
METHODS
This study was carried out from March 22, 1996 to April 29, 1996. The target populations were middle and high school students(middle school-1,369, high school-966 students) in Namseonri. They were given a questionnaire containing sociodemographic characteristics, past vaccination history and rubella-like symptoms. We selected 70 clinically diagnosed patients and 233 students with rubella-like symptoms from the questionnaires. Through IgM and IgG ELISA we analyzed the serum of selected students. All of the middle and high school students except those with clinical rubella were vaccinated on March 27.
RESULTS
1) The number of IgM positive students was 65 among 303 selected students. 58 students among the IgM positive group were diagnosed clinically, and 7 patients and subclincal infection. 2) Male patients were more predominant than female, especially in high school(M : F, 2 : 1 in middle school, 7 : 1 in high school). 3) Positive rates of IgG gradually increased by grade from 58.3% to 92.9% (1st grade of middle school to 3rd grade of high school). 4) IgG titer of the booster vaccinees(2nd and 3rd tirade female, high school) was significantly higher than younger female students(p<.05). 5) After mass vaccination, 3 more patients caught rubella in high school during 1 month follow-up.
CONCLUSIONS
Among 2335 students, IgM positive patients were 65 with incidence rate of 2.8%. Mass vaccination of the studentg an effective preventive method in a rubella outbreak.