MODELING THE DYNAMICS OF ACUTE RESPIRATORY INFECTIONS IN THE COMMUNITY

"SARS-CoV-2, Influenza A/B viruses (Influenza) and Respiratory Syncytial Viruses (RSV) are leading causes of hospitalizations for Acute Respiratory Infection (ARI). The COVID-19 crisis has evidenced that surveillance tools are essential to monitor virulence, transmission and to characterise viral evolution of ARIs1,2. For that purpose, the National Reference Centers for Respiratory virus (CNR, Hospices Civils de Lyon and Institut Pasteur Paris) have developed a collaborative project with the two main networks of community laboratories covering mainland France, Cerballiance and Biogroup (RELAB Laboratories, >1500 laboratories). Since 2023, all samples undergoing a virological PCR test for a suspicion of ARI in RELAB laboratories are analysed with a triplex PCR test (RSV, Influenza, SARS-CoV-2) and transmitted to the CNRs. As of today, nearly 1 million results have already been collected and are available, corresponding to the 2023-24 and 2024-25 seasons. Community-based PCR tests are relatively easy to develop, scalable, and rapidly deployable. However, they are noisy and inherently biased toward the tested population. Their effective use and interpretation thus require rigorous mathematical and statistical modelling, which our approach aims to develop and eval ate. This, therefore, will provide to the epidemiological and modelling community a novel analytical tool that can be applied for current ARIs, but may also be applicable to future emerging epidemics to study virological factors driving pathogen dynamics and transmission in the general community. "