The median age of 30 COVID-19 confirmed children was 5.29 years (IQR: 3.04-7.61), while that of 32 influenza A infected children was 7.09 years (4.08-11.05) (shown in Table 1). Overall, 63.33% of COVID-19 children were girls and the influenza A group showed the opposite portion with 59.38% of boys. Comparison on onset symptoms showed that instead of 100% exhibition of both fever and cough in influenza A infected children, only 43.33% (p<0.001) and 26.67% (p<0.001) patients represented fever and cough respectively in COVID-19 infected cases.
On admission day, lymphocyte count and serum lactate dehydrogenase (LDH) were elevated dramatically beyond the normal ranges in both two groups. One the other hand, compared with extremely higher levels of serum C-reactive protein (CRP), procalcitonin (PCT) as well as erythrocyte sedimentation rate (ESR) in influenza A infected children, those of COVID-19 patients were considered within the normal ranges. Particularly, COVID-19 children had significantly less severe neutrophilia with an average count of 29.6x10^9/L (95%CI: 20.06-38.72 x 10^9/L), while that of influenza A patients was as higher as 58.07x10^9/L (46.04-73.08 x10^9/L).
Once they were admitted to hospital, total (100%) influenza A patients represented fever with the average body temperature of 39.5℃ (39.3-39.7℃). While only 13 (43.3%) COVID-19 children exhibited with fever on the significantly lower (p<0.001) average body temperature of 38.3℃ (37.8-38.8℃). After 3 days of hospital stay, there remained 23 influenza A patients with continuous fever on average of 38.8℃ (38.5-39.1℃). In contrast, only 5 COVID-19 children’s body temperature were hotter than 37.5℃ (shown as Figure 1A & B). Simultaneously, with 3 days of hospital care, the influenza A infected children represented with significantly decreased WBC, neutrophil and lymphocyte counts (shown as Figure 1C-E). On the contrary, there is nearly no change on those of COVID-19 patients. Remarkably, both patients showed obviously elevated platelet levels (shown as Figure 1F). Besides, radiographical imaging indicated that typical pneumonia patterns of initial 23 (71.88%) influenza A patients predominately had obvious improvements in 3-5 days. In contrast, 9 (30%) OCIVD-19 children showed few changes in extent of the ground-glass opacities and another 2 children represented increased parenchymal density. Subsequently, all influenza A patients recovered after an average of 5.31 days (4.58-6.04) of hospitalization. 7 COVID-19 children were still in hospital with 15 to 21 days of current stays and the average length of hospital stay was 15.53 days (13.91-17.16).
Further pearson correlation analysis indicated that there were substantially significant positive correlations between the degree of body temperature and these immunological parameters on admission day for COVID-19 patients (shown in Table 2, WBC: r=0.414, p=0.028; HB: r=-0.387, p=0.042; CRP: r=0.509, p=0.011; PCT: r=0.51, p=0.013). Dissimilarly, only admission PCT level was significantly correlated with the body temperature of influenza A children.