Data analysis:
We divided all suspected patients into the control and case groups based on RT-PCR test results. The case group included the suspected patients with a positive RT-PCR result, and the control group consisted of patients with a negative RT-PCR result. Continuous and categorical variables were compared using t-test, Mann-Whitney U test and Chi square test, cross tabulation between RT-PCR positive and negative groups, respectively. The data were expressed as mean ± standard deviation (SD) and median, interquartile range (IQR) in continuous variables and frequency (percentage) in categorical data. The SPSS software version 22.0 was used for statistical analysis and P<0.05 was considered statistically significant.