Coronavirus disease 2019 (COVID-19) has been diagnosed in nearly 3 million individuals around the globe, of whom around 0.2 million have died. 1 Many patients with COVID-19 develop severe acute respiratory illness requiring admission to intensive care units (ICU) and often mechanical ventilation. 2 The case fatality rate in COVID-19 may be as high as 2.3% overall 2 and from 10% to 40% among severely affected individ uals. 3,4 There is an urgent need for effective therapies.Emerging epidemiologic and clinical data show both similarities and differences between severe COVID-19 and severe acute respiratory syndrome (SARS) and Middle East respiratory syn-drome (MERS). 5 Similarly, treatment strategies for severe influenza infections tested during the H1N1 pandemic and H5N1 and H7N9 outbreaks could inform the care of patients with severe COVID-19. 6 Of the treatment options proposed for COVID-19, 7 convalescent plasma has evidence suggesting a mortality benefit for Ebola virus infection. 8 This intervention has also been tested in other severe acute viral respiratory infections. 6,9,10 "Convalescent plasma" refers to plasma obtained from individuals recently recovered from a viral illness, which is expected to contain the highest levels of polyclonal antibodies directed against the RESEARCH Efficacy and safety of convalescent plasma for severe COVID-19 based on evidence in other severe respiratory viral infections: a systematic review and meta-analysis