Influenza Cases Largely Underreported in Winter Deaths, Study Finds
April 19, 2026 | Barcelona A new population-based study presented at a global infectious diseases conference has found that influenza infections may be significantly underreported in winter mortality records, with a large gap between detected cases and those officially documented as causes of death. The research, conducted over four influenza seasons in Spain, indicated that while the virus was identified in a notable share of winter deaths through postmortem testing, only a small fraction of these cases were reflected in official death certificates, suggesting substantial underestimation of influenza-related fatalities. The study analysed hundreds of deaths during periods of elevated seasonal mortality and involved postmortem testing for a wide range of respiratory viruses. Findings showed that many individuals who tested positive for influenza had not been diagnosed prior to death, and a considerable proportion had not been hospitalised, pointing to missed detection in both community...