An outbreak investigation of chickenpox in a Buddhist school, Bangna District, Bangkok, Thailand, 29 April–1 August 2016

Abstract

Background: A chicken pox outbreak was detected among Buddhist novice in a Prapariyuttuthamawat School, Bangna District, Bangkok. We conducted outbreak investigation in the school with aims to verify diagnosis, confirm outbreak, describe epidemiological characteristics, determine risk factors, and give a specific recommendation for prevention and control measures.
Methods: A descriptive study was conducted. We did active case finding in the school. The suspected case definition of chickenpox was any Buddhist novice in the school who developed a multiple stage of rash included maculupapular, vesicle, pustule or scales in multiple body area in the same time during 29 April – 1 August 2016. Case was interviewed with a standard questionnaire. Laboratory investigation was confirmed by VZV-IgM by ELISA for 6 cases and Tzank smear for 6 cases. Analytic epidemiological study was performed by case-control study and performed multiple logistic regression for get rid of confounder. Environmental survey in the school was also carried out.
Results: Total 78 cases were met case definition with attack rate was 26.53%. Median age was thirteen years old (range 12-17 years old). Six cases (50%) were confirmed by positive ELISA-IgM (5) and Tzank smear (1). The most common clinical presentation was vesicle (98.70%) and form scales (53.80%). Propagated source outbreak pattern was described. Independent risk factor in the multiple logistic regression models was closed contact with the case (adjusted odds ratio = 8.29, 95% CI 1.03–66.57).
Conclusions and discussions: Varicella vaccine campaign was benefit in emergency of outbreak and prevents the future outbreak. Prevention measures recommendation included health education, early detection and prompted case isolation should be focused for successful control. There was no additional case after followed up for 42 days.