Modeling the systemic risks of COVID-19 on the wildland firefighting workforce

Belval, E. J.; Bayham, J.; Thompson, M. P.; Dilliott, J.; Buchwald, A. G.

Wildfire management in the US relies on a complex nationwide network of shared resources that are allocated based on regional need. While this network bolsters firefighting capacity, it may also provide pathways for COVID-19 transmission between fire sites. We develop an agent-based model of COVID-19 built on historical wildland fire assignments using detailed dispatch data from 2016-2018, which form a network of firefighters dispersed spatially and temporally across the US. We use this model to simulate SARS-CoV-2 transmission under several intervention scenarios including vaccination and social distancing. We find vaccination and social distancing are effective at reducing transmission at fire incidents. Under a scenario assuming High Compliance with recommended mitigations (including vaccination), infection rates, number of outbreaks, and worker days missed are effectively negligible. Under a contrasting Low Compliance scenario, it is possible for cascading outbreaks to emerge leading to relatively high numbers of worker days missed. The current set of interventions in place successfully mitigate the risk of cascading infections between fires, and off-assignment infection may be the dominant infection concern in the 2021 season. COVID-19 control measures in place in wildfire management are highly beneficial at decreasing both the health and resource impacts of the ongoing pandemic.