Investigation of COVID-19 Outbreak in Chiang Dao District, Chiang Mai Province

Abstract

The Disease Control Section of Chiang Dao Hospital received a report on July 25, 2021 about an outbreak of COVID-1 before the Section had immediately responded for an investigation of 200 individuals having close contact with the patients. The aims of case investigation required to confirm the evidence, to describe epidemiological characteristics, to define the risk factors, and to find out a surveillance method to control the outbreak of COVID-19. This study was a descriptive epidemiology of asymptomatic and symptomatic COVID-19 patients based on PCR SARS-CoV-2 reports confirmed by Nakornping Hospital laboratory and Regional Medical Sciences Center 1 Chiang Mai. Epidemiological analysis of COVID-19 based on the retrospective cohort study with univariate and multivariate methods for the risk factors. Findings indicated 27 confirmed cases (crude incidence rate was 81.76 per 100,000 persons) found not severely ill or dead. Cough was the most common symptom (81.48%). Multiple exposure increased risk of COVID-19 infection 13.55 times (95%CI=2.57-71.55) more than single exposed. A social activity contact was the highest risk for COVID-19 infection 12.39 times compared to a household contact, workplace, and market (95%CI=1.54-99.38). And high risk persons who exposed to symptomatic patients had 4.69 times more infective than those contacted with patients before onset of the symptoms (95%CI =1.68-13.15). The disease had been controlled after the patients and high risk contacted persons were isolated and quarantined, the risky places were closed for 14 days, social activities were refrained, and the D-M-H-T-T-A prophylaxis procedure was emphasized.