Longitudinal trends in the endemic symptomatic burden of COVID-19: Insights from community-based participatory virological surveillance in the Netherlands, November 2020 – April 2025

This article presents a large-scale, longitudinal analysis of symptom patterns and the perceived disease burden of COVID-19 in the Netherlands, covering a 4.5-year period from November 2020 to April 2025. Using data from “Infectieradar,” a participatory surveillance platform with nearly 39,000 participants, the authors evaluate how symptoms, self-reported health, and testing behavior evolved as SARS-CoV-2 transitioned from a pandemic to an endemic virus. The study also compares the symptomatic burden of COVID-19 to influenza and other common respiratory viruses. One of the central findings is the shift in symptomatology over time. Early in the pandemic, classic COVID-19 symptoms such as anosmia and ageusia were prominent. This pattern changed significantly with the emergence of Omicron variants from late 2021 onward. Symptoms increasingly resembled upper respiratory viral infections, with a higher likelihood of rhinorrhea, sore throat, and sneezing. Meanwhile, systemic symptoms such as fever and chills remained largely stable, and gastrointestinal symptoms decreased....