Performance of suspected influenza case definitionbefore and during the COVID-19 pandemic

Murillo-Zamora, E.; HERNANDEZ-SUAREZ, C. M.

Background: The influenza-related burden remains high and the COVID-19 pandemic may difficult its accurate surveillance. This study aimed to evaluate the performance, before and during the COVID-19 pandemic, of the case definition of suspected influenza used in community surveillance in Mexico. Methods: A cross-sectional analysis of a cohort study took place and cases fulfilling the suspected case criteria (n = 20,511), and with laboratory-conclusive evidence (quantitative real-time polymerase chain reaction) to confirm or discard influenza virus infection were analyzed. Results: A high sensitivity and modest specificity were documented, and this later decreased during the COVID-19 outbreak, as well as its diagnostic accuracy. However, no significant differences were observed in the Area Under the Receiver Operating Characteristics among the analyzed periods. Conclusions: The evaluated case definition remains to be a cost-effective alternative to identify patients who may benefit from influenza-specific antiviral drugs, even during the COVID-19 global outbreak.