First-generation Cluster of Coronavirus Disease 2019 (COVID-19) Related to Boxing Stadiums in Bangkok and the Bangkok Metropolitan Region, March 2020

Abstract

In March 2020, clusters of COVID-19 cases were reported among attendees of a boxing stadium in Bangkok. This study aimed to investigate and describe the outbreak and identify its source. We conducted a descriptive analysis of cases and transmission patterns, performed a walk-through survey and interviewed stadium staffs for possible factors related to disease spreading. COVID-19 cases were those who had a history of visiting Bangkok or the Bangkok Metropolitan boxing stadiums, or contacting confirmed cases visiting boxing stadiums within 14 days of developing symptoms with laboratory confirmation using the RT-PCR method. An active case finding was accomplished through social media and the national disease surveillance system. High-risk contacts were self-quarantined and nasopharyngeal specimens were collected. Attack rate among boxing event attendees on 6 Mar 2020 was 11.0% (268/2,431). Attack rate among contacts of the first generation was 5.4% (110/2,024), and the second-generation contacts was 2.6% (6/229). Behavioral risks during the event included cheering and gambling among attendees. Some did not wear face masks. We recommend postponing all sporting matches as the most reasonable practice during an epidemic. To prevent and control future outbreaks, gambling should be restricted or limited to online payment and strict control measures should be considered.

Keywords: COVID-19, boxing stadiums, Thailand