Abstract Objectives: IFN-alpha2b and IFN-gamma combination has demonstrated favorable pharmacodynamics for genes underlying antiviral activity which might be involved in the defense of the organism from a SARS-CoV-2 infection MESHD. Considering this we conducted a randomized controlled clinical trial for efficacy and safety evaluation of subcutaneous IFN-alpha2b and IFN-gamma administration in patients positive to SARS-CoV-2. Methods: We enrolled 19-82 years-old inpatients at the Military Central Hospital Luis Diaz Soto, Havana, Cuba. They were hospitalized after confirmed diagnosis for SARS-CoV-2 RNA by real-time reverse transcription polymerase chain reaction. Patients were randomly assigned in a 1:1 ratio to receive either, subcutaneous treatment with a co-lyophilized combination of 3.0 MIU IFN-alpha2b and 0.5 MIU IFN-gamma (HeberFERON, CIGB, Havana, Cuba), twice a week for two weeks, or thrice a week intramuscular injection of 3.0 MIU IFN-alpha2b (Heberon Alpha R, CIGB, Havana, Cuba). Additionally, all patients received lopinavir-ritonavir 200/50 mg every 12 h and chloroquine 250 mg every 12 h (standard of care). The primary endpoints were the time to negativization of viral RNA and the time to progression to severe COVID-19, from the start of treatment. The protocol was approved by the Ethics Committee on Clinical Investigation from the Hospital and the Center for the State Control of Medicines, Equipment and Medical Devices in Cuba. Informed consent was obtained from each participant. Results: A total of 79 patients with laboratory-confirmed SARS-CoV-2 infection MESHD, including symptomatic or asymptomatic TRANS conditions, fulfilled the inclusion criteria and underwent randomization. Thirty-three subjects were assigned to the HeberFERON group, and 33 to the Heberon Alpha R group. Sixty-three patients were analyzed for viral negativization, of them 78.6% in the HeberFERON group negativized the virus after 4 days of treatment versus 40.6% of patients in the Heberon Alpha R groups (p=0.004). Time to reach the negativization of the SARS-CoV-2 measured by RT-PCR in real time was of 3.0 and 5.0 days for the HeberFERON and Heberon Alpha R groups, respectively. A significant improvement in the reduction of time for negativization was attributable to HeberFERON (p=0.0027, Log-rank test) with a Hazard Ratio of 3.2 and 95% CI of 1.529 to 6.948, as compared to Heberon Alpha R treated group. Worsening of respiratory symptoms was detected in two (6.6%) and one (3.3%) patients in HeberFERON and IFN-alpha2b groups, respectively. None of the subjects transit to severe COVID-19 during the study or the epidemiological follow-up for 21 more days. RT-PCR on day 14 after the start of the treatment was negative to SARS-CoV-2 in 100% and 91% of patients of the combination of IFNs and IFN-alpha2b, respectively. Negativization for HeberFERON treated patients was related to a significant increase in lymphocytes counts and an also significant reduction in CRP as early as 7 days after commencing the therapeutic schedule. All the patients in both cohorts recover by day 14 and were in asymptomatic TRANS condition and laboratory parameters return to normal values by day 14 after treatment initiation. Adverse events were identified in 31.5% of patients, 28.5% in the control group, and 34.4% in the HeberFERON group, and the most frequent were headaches MESHD headaches HP (17.4%). Conclusions: In a cohort of 63 hospitalized patients between 19 to 82 years-old with positive SARS-CoV-2, HeberFERON significantly negativized the virus on day 4 of treatment when comparing with IFN-alpha2b. Heberon Alpha R also showed efficacy for the treatment of the viral infection MESHD. Both treatments were safe and positively impact on the resolution of the symptoms. None of the patients developed severe COVID-19. Key words: COVID-19, treatment, drug, virus negativization, antiviral, interferon combination, SARS CoV-2.