31 March 2026
Epidemics of acute respiratory infections (especially influenza) represent a major health issue during the winter season. Two recent publications have contributed to a better understanding of how weather has affected influenza activity and human mortality in the Czech Republic over the past four decades (1982–2020).
Hana Hanzlíková et al. (2026) found significant associations between weather – particularly temperature – and the variability and severity of influenza epidemics in terms of their impact on human mortality. Epidemics associated with high mortality tended to follow relatively cold winter periods (below-average temperatures) and were predominantly linked to the A/H3N2 virus subtype. In contrast, epidemics with a weaker impact on mortality were more likely to occur during relatively warm periods (average or above-average temperatures) and were associated with other virus types (such as A/H1N1).
An analysis by Ekaterina Borisova et al. (2026) provided further insight into how respiratory infections modify the impact of cold weather on mortality. The results showed that while cold weather places stress on the human body and increases the risk of death, it also promotes the spread of acute respiratory infections, which in turn contribute to higher mortality. The analysis suggests that approximately 12% of cold-related deaths in the period 1982–2019 could be attributed to the mediating effect of respiratory infections.
Taken together, these findings highlight that excess winter mortality is driven by a combination of direct temperature effects and indirect effects mediated through infectious diseases. They also demonstrate that the severity of influenza epidemics depends not only on meteorological conditions but also on the circulating virus subtype. This improved understanding is important for anticipating health risks and designing more effective public health responses to seasonal mortality patterns.
Reference:
- Hana Hanzlíková, Plavcová, E., Kyselý, J., Kynčl, J., Malý, M., Urban, A., 2026: Links between influenza epidemics weather characteristics and all-cause mortality in the Czech Republic, 1982–2020, BMC Public Health, 26 (1), 189, doi.org/10.1186/s12889-025-25861-9
- Ekaterina Borisova, Ballester, J., Hanzlíková, H., Plavcová, E., Kyselý, J., Kynčl, J., Urban, A., 2026: The mediating role of acute respiratory infections in temperature-mortality associations in the Czech Republic, 1982–2019, International Journal of Biometeorology, 70, 84.