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Variations in global climate patterns have long been linked to the spread of infectious diseases, with changing temperatures, precipitation, and humidity altering the habitats of vectors such as mosquitoes and influencing disease transmission rates. A recent study published in GeoHealth by Maya V. Chung and colleagues explores how the El Niño–Southern Oscillation (ENSO) impacts immunity and outbreak patterns over multiple years.
ENSO consists of alternating warm (El Niño) and cold (La Niña) phases, both of which can contribute to extreme weather events and disruptions in public health responses. Previous studies have indicated that ENSO plays a role in the spread of diseases such as cholera, dengue, malaria, respiratory syncytial virus (RSV), and Rift Valley fever. However, despite the ability to forecast ENSO events months in advance, public health interventions based on these predictions have remained limited.
Modeling ENSO-Disease Interactions
Chung and collaborators expanded upon previous studies by developing long-term models to analyze the influence of ENSO on various infectious diseases. The researchers used two approaches: first, they examined how consecutive ENSO events affected population susceptibility over multiple years for a generic seasonal disease. Second, they analyzed humidity data from 1981 to 2017 to assess how ENSO-driven humidity changes influenced the spread of the airborne human coronavirus HCoV-HKU1.
One key finding was that immune responses to infectious diseases often lagged behind initial ENSO events, sometimes by more than a year. When ENSO events occurred in succession, the resulting effects could amplify disease spread and prolong outbreaks. This delay underscores the complexity of linking ENSO cycles directly to disease outbreaks and highlights the need for enhanced predictive measures.
Implications for Public Health Planning
Given the study’s findings, the researchers recommend that risk managers consider population immunity levels as a critical factor when assessing ENSO’s potential impact on disease outbreaks. Improved understanding of climate-disease interactions could enable health authorities to implement targeted interventions months in advance, thereby mitigating the severity of future outbreaks.
Future Directions
While this study provides valuable insights, further research is needed to refine predictive models and improve public health preparedness. The interplay between ENSO, immunity, and disease transmission remains a complex field requiring multidisciplinary collaboration.
Disclaimer: This article is based on the study Intersecting Memories of Immunity and Climate: Potential Multiyear Impacts of the El Niño–Southern Oscillation on Infectious Disease Spread by Maya V. Chung et al., published in GeoHealth (2025). The information presented is for educational and informational purposes only and should not be used as a substitute for professional medical or climate-related advice.
