Data analysis was performed using SPSS 17.0 (IBM Corp., Armonk, NY) software. Categorical variables were summarized using frequencies and percentages, and continuous data are presented as the medians (interquartile ranges [IQRs]). Chi‐square test was used for categorical variables, and nonparametric rank sum test of independent samples was used for continuous variables. Variables with a p value <0.05 in chi‐square test and rank sum test were entered into multivariate logistic regression analysis to identify independent risk factors associated with COVID‐19 or influenza A. All of the p values less than 0.05 were considered to be statistically significant.