Publication date: Apr 01, 2025

This study presents findings captured in the first 1. 5 years of the Virus Monitoring in Denmark (VMD) surveillance system. It describes trends in respiratory viruses, related symptoms, and participant demographics and behaviors. VMD used self-swabbing and self-reported symptoms to monitor respiratory viruses in the general population. Participants were recruited via digital invitations to a representative sample of the population or through workplaces. Symptomatic participants could self-swab and register their samples and report their symptoms via a dedicated smartphone web app. With 30 627 participants and 12 642 samples analyzed, VMD had a broad demographic representation. SARS-CoV-2 was the most frequently detected virus, with positivity rates peaking at over 50% in late 2023. Participants commonly self-swabbed because of fever, cough, and rhinorrhea, with influenza A linked to the highest median number of symptoms. Participants only provided samples after reaching a specific symptom threshold, and participation affected the health-seeking behaviors and work attendance of a few individuals. VMD continuously provided real-time insights into respiratory virus trends and symptomatology in the general non-healthcare-seeking population. Its accessibility – available to anyone with a Danish identification number, a smartphone, and an invitation – highlights its potential as a pandemic preparedness tool.

Semantics

Original Article