Investigation of the COVID-19 outbreak at a cement pipe factory in Mueang Samut Prakan District, Samut Prakan Province among April-May 2021

Abstract

On May 5th, 2021, the Operation team of the Office of Disease Prevention and Control 6 Chonburi was notified by Samut Prakan Provincial Public Health Office that there were at least 10 confirmed cases of COVID-19 infection which were the employee of a cement pipe manufacturing factory in Samut Prakan, therefore the investigation started to confirm an outbreak, epidemiology, factors and to control the outbreak between May 5th to 26th, 2021. A descriptive study was conducted. The finding revealed that there were 147 COVID-19 patients from a total of 295 factory employees and the attack rate was 11.35%. The ratio of females to males was 1:5. The nationalities of the patients were 76% Thai and 24% Burmese. The age groups with the highest infection were 20 - 59 years old while the mean of all confirmed cases was 37 years old and the range was 13 – 63 years old. 88.40% of the patients were asymptomatic, 11.60% had mild symptoms and there was no severe case or death. For this outbreak, the variant of Potentially B.1.1.7 (Alpha) was found. From the factory survey, close contact when working, eating, and, living in houses and not wearing masks were suggested as the risk factors. The outbreak of this factory was expectedly caused by the employee coming back from their homes in other provinces during the Songkran festival which was precipitated by the close contact with the infected. After dividing and secluding the employee into small groups (small bubbles) and emphasizing the importance of wearing masks, the outbreak was successfully controlled within 28 days after the disease control.