Purpose: Since February 2020, the world has been overwhelmed by the SARS-CoV-2 outbreak, and several patients suffered interstitial pneumonia and respiratory failure requiring mechanical ventilation, threatening the capability of healthcare systems to handle this amount of critical cases. Intravenous immunoglobulins (IVIG) possess potential immunomodulatory properties beneficial for COVID-19 patients, yet evidence supporting IVIG as adjunctive therapy remains sparse. This study evaluated the outcomes of adjunctive IVIG with the standard of care (SoC) in moderate-to-severe COVID-19 patients.

Methods: This randomized study included 59 moderate-to-severe COVID-19 patients with known comorbidities. One arm (n = 33) received high-dose IVIG (400 mg/kg/day) within 48 hours for five days alongside SoC, while the other arm (n = 26) received SoC, comprising steroids, enoxaparin, and remdesivir. The primary endpoint was clinical improvement, as measured by the National Early Warning Score 2 (NEWS2) and discharged/death proportions. Secondary outcomes included IVIG safety, hospitalization duration, changes in oxygen saturation, inflammatory markers, IgG titer, CTSS (CT severity score), and radiological findings.

Results: There was an improvement in the NEWS2 at the end of treatment in the IVIG arm (5.67 vs. 5.96). A significant absolute effect improvement (Day 1 vs. Day 9) was seen in serum LDH, D-dimer, hs-CRP, IL-6, CTSS, procalcitonin, respiratory rate, and chest radiographic findings. SARS-CoV-2 IgG titer increased significantly in the IVIG arm. There was a statistically significant reduction in mortality in the IVIG group (5 vs. 10).

Conclusion: IVIG was a safe and effective adjunctive therapy to SoC treatment in moderate-to-severe COVID-19 patients needing ventilatory support. Furthermore, studies are required to validate our findings. This trial is registered with CTRI/2021/05/033622.