Objective: This study evaluates public health prevention measures implemented during the COVID-19 pandemic for organizing a complex mass gathering event (MGE), and to identify practices applicable to future MGEs.
Methods: The study analyzed COVID-19 surveillance data from the 2022 Iditarod Trail Race alongside Alaska Department of Health COVID-19 reports to assess the effectiveness of a comprehensive prevention plan established to protect those involved with or near the race from COVID-19. This plan included a 'bubble' strategy to separate participants into designated groups, a multi-tiered daily testing approach (including pre-bubble testing), mandatory mask-wearing, vaccination requirements, and isolation of positive cases until two consecutive negative tests.
Results: Among the 622 participants, 18 (2.9 %) tested positive for COVID-19. Pre-arrival and pre-trail testing identified 17 (94 %) of cases, effectively preventing transmission on the trail. One case accounted for 67 % of the transmission in the headquarters bubble, while another asymptomatic case was detected on the trail during daily testing. No known transmission occurred from this case to community members or the trail bubble.
Discussion: Implementation of prevention strategies during the 2022 Iditarod-including the bubble strategy, daily testing, mask mandates, vaccination requirements, and isolation protocols- successfully prevented most transmission among race participants. The lack of sustained transmission combined with low community case counts provides evidence that the race did not increase transmission during this large-scale MGE, across 1000 miles and 23 communities. These findings demonstrate the effectiveness of combined strategies in protecting both participants and communities, while allowing a major sporting event to proceed.
Keywords: Bubble strategy; COVID-19; Iditarod; Mass gathering events; Prevention.
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