The integrated respiratory surveillance demonstrated a substantial burden of Mycoplasma pneumoniae infections and hospitalisations in Denmark, week 40 2023 to week 46 2024

In Denmark, an integrated surveillance system was established to support preparedness and healthcare planning by providing timely information on transmission intensity and hospital admissions. The aim of this study was to describe the relative contribution of Mycoplasma pneumoniae to respiratory infections and associated admissions compared with other monitored respiratory pathogens during 2023–2024. Real-time data on laboratory-confirmed respiratory infections obtained from the Danish National Microbiology Database were linked to nationwide registries, to quantify weekly detections and associated hospital admissions as well as admissions identified in the surveillance system for severe acute respiratory infections (SARI). Between week 40, 2023, and week 12, 2024, M. pneumoniae co-circulated with SARS-CoV-2, influenza virus, Bordetella pertussis , and RSV. Among the five monitored pathogens, M. pneumoniae accounted for 17.5% of the laboratory-confirmed respiratory detections and 6.8% of associated hospital admissions. Between week 13 and 46, 2024, M. pneumoniae detections remained elevated making it the dominant respiratory pathogen and from week 31 to 46, weekly detections further surged from 659 to 2,522 per week, while hospital admissions increased from 68 to 135. During the latter period, M. pneumoniae accounted for 72.8% of all detections and 33.1% of associated hospital admissions among the five monitored pathogens, while M. pneumoniae was detected in 38% of laboratory-confirmed SARI cases. This study showed that M. pneumoniae contributes substantially to infections and admissions due to respiratory pathogens. These findings support the expansion of existing surveillance systems to cover more pathogens to support public health awareness and healthcare planning.