Robust data integration methods for understanding associations between climate change and hantavirus infection in Europe are needed: A systematic-narrative hybrid literature review

The relationship between climate change and human hantavirus infection is complex, involving not only climate itself but also environmental conditions, rodent host ecology, and human behavior. Understanding this broader causal pathway requires careful integration of diverse data sources. Compared with well-studied vector-borne diseases, human hantavirus infection remains less explored, partly because its transmission pathways are more complicated to characterize. To assess how current evidence addresses this complexity, particularly the data and methods used, we reviewed empirical studies examining associations between climatic factors and human hantavirus infection in Europe. Thirteen studies were identified through a systematic approach. Using a tailored evaluation framework, we assessed their analytical approaches, including spatial and temporal resolution, lag effects, and handling of modifying and mediating variables. Across studies, we found substantial variation in data and methods. This heterogeneity, combined with differences in scale and variable selection, has led to inconsistent conclusions about whether and how climate influences hantavirus risk across different European regions. Our review highlights the need for more robust, coherent methodological strategies and explicit causal frameworks to clarify the relationships between climate and hantavirus infection and to support future surveillance and public health action.