Comparison of Hospitalized Patients with Severe Pneumonia Caused by COVID-19 and Highly Pathogenic Avian Influenza (H7N9): A Retrospective Study from A Designated Hospital

Abstract Background Considerable attention has been focused on clinical features of Coronavirus Disease 2019 (COVID-19), it is also important for clinicians to differentiate it from influenza virus infections. Methods The clinical data of 23 cases of H7N9 and 23 cases of COVID-19 with severe pneumonia were collected. The comparisons were performed with the t test, Mann-Whitney U test, Fisher exact test or the chi-squared test, and multivariable logistic regression analysis. Results All of the cases were under the circumstance of sufficient medical staff and medical supplies. The rate of coexisting disease was lower in the severe COVID-19 group than in the severe H7N9 group (p < 0.05). Radiologically, severe COVID-19 patients had less consolidation and pleural effusion, but more crazy-paving pattern than severe H7N9 patients (p < 0.05). Clinically, compared to severe H7N9, severe COVID-19 patients were more inclined to surfer to relative better disease severity score, less secondary bacterial infection, a shorter time to beginning absorption on CT, but a longer duration of viral shedding from the admission (p < 0.05). Although more severe H7N9 patients needed non-invasive respiratory support, these two groups ultimately yielded comparable mortality. Based on multiple logistic regression analysis, severe COVID-19 infection was associated with a lower risk of the presence of severe ARDS (OR 0.964, 95% [CI] 0.931–0.998, p = 0.040), but exhibited longer duration of viral shedding (OR 0.734, 95% [CI] 0.550–0.980, p = 0.036) than severe H7N9 infection. Conclusion Although the conditions of severe H7N9 patients seemed to be more critical than those of severe COVID-19 patients, the relatively lower mortality of these two severe cases is to be expected in context of sufficient medical supplies.