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

Murillo-Zamora, E.; Hernández-Suárez, C.

Objective 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.