Study design and participants
This retrospective cohort study was conducted on confirmed SARS-CoV-2 infected patients who were admitted to Beijing Ditan Hospital from Jan.13 2020 to Apr. 23. The institutional review boards approved this study and patient-level informed consent was waived owing to its retrospective nature. SARS-CoV-2 infection was diagnosed by RT-PCR assay of respiratory tract samples tested by the local Center for Disease Control or by our institutional laboratory. Pneumonia was defined as new, lower respiratory tract symptoms such as fever or chills, cough or shortness of breath, and new focal chest signs, coinciding with new onset or progressive pulmonary infiltrates on chest radiography. The severity of COVID-19 was defined in accordance with the China’s COVID-19 management guidelines (version 7.0).
All confirmed patients were offered treatment with standard care including as necessary, supplemental oxygen, antibiotic agents, or traditional Chinese medicine. The potential antiviral therapy for SARS-CoV-2 assigned two groups: receiving Kaletra (500 mg twice daily, orally) plus interferon alfa-2b (interferon, 5 million units twice daily, nebulization) or interferon alfa-2b alone. Initially, a total of 196 cases were identified (Figure 1.). Among these, cases (n=29) were excluded for patients who were younger than 18 years and critically ill patients. Among the 167 remaining participants, cases were excluded (n=44)on the basis of other antiviral therapy including oseltamivir, chloroquine phosphate, and ribavirin. Eventually, 123 participants were enrolled in the study. The main exposure divided into two groups: Kaletra plus interferon alfa-2b therapy (n=67), defined as the use of Kaletra and interferon alfa-2b combination, and interferon alfa-2b alone (n=44). The comparator group was treatment with standard care without use of Kaletra and interferon alfa-2b(n=12).The final groups for the 123 included cases were: standard care group (n=12), interferon alfa-2b group (n=44), Kaletra plus interferon alfa-2b group (n=67).