The Study of Distribution of HI Antibody Titers Aganist Japanese Encephalitis Virus Among Children in Seoul

ABSTRACT

PURPOSE: Incidence of Japanese encephalitis has been markedly decreased, but this disease is known to be high and lethal in the young age group. This study was designed to find out the HI antibody titers and associated factors of Japanese encephalitis of children in Seoul, and to establish the plan of vaccination. METHODS: The survey was conducted from the end of May to the beginning of June, 1992. Serum of total 862 children aging from 4 year to 15 year in the Kangseo-ku and Songpa-ku, Seoul wre obtained. And we analyzed the HI antibody titers to Japanese encephalitis virus. RESULTS: 1) The percentage of childrens with the antibody titer higher than 120 was 34.5%. 2) The protective HI antibody to Japanese encephalitis virus by sex revealed that the percentage of males was 47% while that of females was 29.2% 3) The protective HI antibody titer to Japanese encephalitis was higher in the younger age than older age. 4) The comparative studies on HI antibody titer of Japanese encephalitis virus by vaccination types revealed that the percentage of children without vaccination was 0%, the percentage of children with single vaccination at 2 years ago was 9.7%, single vaccination at 1 year ago 31.6%, and single vaccination at this year 39.1%. According to serial vaccination at 1990 and 1991, 1991 and 1992, the percentage of protective HI antibody titer to Japanese encephalitis virus was 22.4%, 44.8%, respectively. 5) The factors influenced on protective antibody titer to Japanese encephalitis virus were age and vacciantion history at 1991 and 1992. CONCLUSIONS: Effective antibody titers to Japanese encephalitis virus of children in Seoul were low and the important factors to maintain protective HI antibody titers were age and recent vaccination history. Therefore regular vaccination of Japanese encephlitis virus is thought to be important in preventing the Japanese encephalitis.