Background: Intravenous immunoglobulin (IVIG) is usually used as supportive therapy, but the treatment of COVID-19 by IVIG is controversial. This rapid review aims to explore the clinical effectiveness and safety of IVIG in the treatment of children with severe COVID-19. Methods: We systematically searched the literature on the use of IVIG in patients with COVID-19, Severe Acute Respiratory Syndrome (SARS) or Middle East Respiratory Syndrome (MERS), including both adults and children. We assessed the risk of bias and quality of evidence and reported the main findings descriptively. Results: A total of 1519 articles were identified by initial literature search, and finally six studies, included one randomized controlled trial (RCT), four case series and one case report involving 198 patients. One case series showed the survival of COVID-19 patients with acute respiratory distress syndrome (ARDS) was not improved by IVIG. One case report showed high-dose IVIG could improve the outcome of COVID-19 adults. Three observational studies showed inconsistent results of the effect of IVIG on SARS patients. One RCT showed that IVIG did not reduce mortality or the incidence of nosocomial infection in adults with severe SARS. The quality of evidence was between low and very low. Conclusions: The existing evidence is insufficient to support the efficacy or safety of IVIG in the treatment of COVID-19.