Airborne Fungal Spores as Predictors of COVID-19 and Flu Outbreaks

Recent research suggests that monitoring airborne fungal spores can serve as an early warning system for surges in respiratory viral infections such as COVID-19 and influenza. Presented at ASM Microbe 2025 in Los Angeles, the study conducted by Félix E. Rivera-Mariani, Ph.D., highlights the potential role of outdoor fungal spores in predicting short-term outbreaks, particularly during the fall season.

The investigation focused on the unique environment of Puerto Rico, which naturally exhibits consistent levels of airborne fungi and pollen throughout the year. Researchers analyzed daily data from 2022 to 2024 in the San Juan and Caguas regions, correlating high concentrations of fungal spores and pollen with increased cases of COVID-19 and the flu.

Using advanced statistical and machine learning models, the team found that elevated levels of fungal spores were strongly associated with subsequent spikes in infections within a few days. Interestingly, pollen levels did not demonstrate a similar predictive relationship. This suggests that fungi, rather than pollen, may influence viral transmission dynamics or serve as environmental indicators.

These findings could enhance public health responses by providing earlier alerts to impending outbreaks, especially in areas with high environmental levels of airborne fungi. Rivera-Mariani emphasizes that environmental factors, alongside person-to-person transmission, could partially drive the incidence of respiratory viruses, opening new avenues for targeted intervention.

Puerto Rico's existing fungal and pollen monitoring stations facilitated this research, demonstrating the practical potential for integrating environmental surveillance into health management strategies. Future research aims to explore whether fungal spore levels correlate with severe health outcomes like hospitalizations and fatalities, and whether similar patterns are observable in other regions.

The study underscores the importance of environmental monitoring in infectious disease forecasting and prevention, potentially empowering public health agencies to implement more effective early warning systems.