Fig. 4

Blood tests results for each of the four groups between the early stage of onset and the disease stage. Blood test results were collected from patients with pneumonia secondary to COVID-19, SARS, AdV, or H1N1 during hospitalization. The data of the early stage of onset were obtained after performing the test closest to the onset date (i.e., within 3 days after hospitalization); information on stage of disease were obtained on the final test (i.e., within 2 days before discharge). Then, the disease course was divided into three equal periods: the initial, obviously symptomatic, and recovery stages. The data were analyzed using SPSS software version 21. P values between 0.01 and 0.05, 0.001 and 0.01, and 0.0001–0.001 were considered statistically significant (*), very significant (**), and extremely significant (***), respectively. P values > 0.01 were considered not significant