All issues > Volume 38(6); 1995

Original Article

J Korean Pediatr Soc. 1995;38(6):778-785. Published online June 15, 1995.

Epidemiology and Vaccine Efficacy of Measles During the 1993 measles Epidemic

Soon Ki SK Kim¹, Jong Woon JW Choi¹, Byong Kwan BK Son¹, Seung Nam SN Park², Churl Young CY Chung², Young Min YM Ahn³, Chong Young CY Park⁴, Ki Yang KY Ryoo⁴, Woo Kap WK Chung⁴, Hoan Jong HJ Lee⁵

¹Department of Pediatrics, College of Medicine, Inha University, Inha Hospital, Seongnam, Korea
²Department of Pediatrics, College of Medicine, Injae University, Sanggyue Paik Hospital, Seoul, Korea
³Department of Pediatrics, Kangnam Hospital Public Corporation, Seoul, Korea
⁴Department of Pediatrics, College of Medicine, Hallym University, Seoul, Korea
⁵Division of Infectious Disease, Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea

Abstract

Purpose
: Because of increased measles incidence in Korea during 1993 and the recent finding of genomic differences between vaccine virus and contemporary wild measles viruses, we conducted a measles vaccine efficacy study involving children ages 1 to 5 yeark, with the demographic analysis of patients brought to the hospitals during measles outbreak that had occurred 1993 in Seoul and Seong-nam city.
Methods
: Reported cases of measles, which were brought to 6 General Hospitals(Inha, Sanggyue Paik, 3 Saint Heart Hospitals, and Kangnam General Hospital Public Corporation) were investigated. We compared the measles attack rates for vaccinated and unvaccinated children to obtain the relative risk(RR) for measles infection of those vaccinated.
Results
: 1) A total of 380 patients(M:F=216:164) participated in this study. Two hundred and nine cases(55.0%) occurred in less than 5 years of age, and 167(43.9%) were under 16 months of age. The highest recorded age-specific incidence rates showed two major outbreak, : those in which of the cases occurred blow 16 months of age and those in which most of cases occurred among school-age persons. 2) Only 9.6%(16/167) in those less than 16 months of age were vaccinated, 59.5%(2.42) in children 16 months to 4 years of age have been vaccinated, and 91.8%(157/171) of the cases in school-aged children have been vaccinated. 3) Attack rated among the 122 vaccinated and 12 unvaccinated children were 5.7% and 75%, respectively. Vaccine efficacy was 92.4%(95% confidence interval : 83.6%, 96.4%). 4) The causes of MMR unvaccination above 15 months of age were mild acute illness not contraindicated to vaccine use in 77.4%(24/31). Neglect or oblivion in 6.4%(2/31).
Conclusion
: The high vaccine efficacy in household exposures suggests that measles outbreaks in Korea are not due to reduced vaccine efficacy. A booster dose of measles vaccine at the time of school entry may be necessary, with the reinforcement of age-appropriate immunization in Korea.

Keywords :Measles, Measles vaccination, Vaccine failure, vaccine efficacy