Systematic Molecular Influenza A/B Screening Upon Hospital Admission in Belgium, January–April 2022: Positivity Ratios and Viral Loads According to Symptomatology, Age, and Vaccination Status

ABSTRACT Three hospitals implemented molecular point‐of‐care tests (POCTs) to screen patients for SARS‐CoV‐2 infection upon admission during the 2021/2022 influenza season, which in Belgium lasted from January to April 2022. The samples were simultaneously tested for influenza A/B. Influenza positivity at admission was examined in relation to patient characteristics and symptomatology. Influenza POCTs were performed on all patients requiring urgent hospitalization, regardless of the admission reason. A total of 9327 patients were included in the study, of which 411 (4.4%) tested positive for influenza A/B. Asymptomatic infection and mild illness accounted for respectively 11.2% (95% CI: 8.5%–14.6%), and 43.3% (95% CI: 38.6%–48.1%) of the cases. A total of 66% (95% CI: 60%–72%) of all patients in these symptom categories (asymptomatic and mild illness) showed a high viral load (cycle threshold [Ct]