Efficacy and safety of interferon alpha-2b aerosol therapy for patients infected with the SARS-CoV-2 omicron variant: A randomized controlled single-blind study

The efficacy of Type I interferon (IFN) in treating COVID-19 has remained controversial. In this study, we conducted a randomized, single-blind clinical trial to evaluate the efficacy of recombinant human interferon alpha 2b (IFN-alpha2b) in treating COVID-19 patients during the Omicron outbreak in Shanghai in 2022. The study cohort included 505 patients, classified as asymptomatic, mild, or moderate based on clinical symptoms. The cohort was divided into an experimental group, which received a 7-day course of nebulized inhalation of IFN-alpha2b, and a control group, which received an identical treatment course using physiological saline in place of IFN-alpha2b. Effectiveness and safety were assessed by measuring the length of hospital stay, improvement in clinical symptoms, and occurrence of adverse events. While there were no significant differences in overall hospital stay or symptom improvement between the two groups, IFN-alpha2b treatment was associated with a significantly shorter hospitalization time in the asymptomatic subgroup. Multivariate Cox regression analysis identified IFN nebulization therapy as a positive predictor of discharge within 12 days, alongside the white blood cell count at admission, and the IL-4 level at admission as a potential negative predictor. Regarding safety, there was no significant difference in the incidence of adverse reactions between the two groups during treatment. Collectively, our study suggests that Type I IFN, when administered via nebulized inhalation, may offer benefits specifically for the asymptomatic subgroup among COVID-19 patients, indicating selective efficacy.