Wildfires May Increase Risk of Flu and COVID-19 Outbreaks
Wildfires may unintentionally lead to a surge in flu and COVID-19 cases, as smoke-filled air drives people indoors, creating ideal conditions for the spread of respiratory diseases. Researchers analyzed mobile phone data and found significant increases in indoor activities in areas heavily affected by wildfires. The study suggests that incorporating simple measures like indoor mask-wearing can mitigate this risk. By understanding the behavioral response to extreme events, public health strategies can evolve to better protect individuals in a warming world.
Key Takeaways:
- The study analyzed mobile phone data tracking over 4.6 million points of interest in the United States, including both indoor and outdoor destinations.
- Wildfires in Oregon and Washington led to a 14% increase in indoor activity in counties in Oregon and a nearly 11% increase in Washington counties.
- Major cities in those states experienced a surge in indoor activities: 16% in Seattle and 11% in Portland.
- Computer models showed that packing extra people indoors increased the risk of infectious disease spread, particularly for virulent airborne diseases like influenza and COVID-19.
- Researchers found that even a 10% increase in mask use can reduce the rise in peak incidence during wildfires.
- In heavily affected areas like Washington County, Ore., and Yakima County, Wash., mask rates above 50% may be required to effectively mitigate disease transmission.
Statistics:
- 4.6 million: Number of points of interest tracked in the mobile phone data analysis.
- 14%: Increase in indoor activity in counties in Oregon due to wildfires.
- 11%: Increase in indoor activity in Washington counties due to wildfires.
- 16%: Surge in indoor activities in Seattle.
- 11%: Surge in indoor activities in Portland.
- 10%: Increase in mask use that can reduce the rise in peak incidence during wildfires.
Sources:
- PLOS Climate, journal
- PLOS, news release, June 18, 2025