5.3.5 Convalescent plasma transfusion
Convalescent plasma has also been utilized as a last resort to improve the survival in patients with miscellaneous viral infections (i.e., SARS, H5N1, H1N1, and Ebola virus infection) (Chen et al., 2020b). The theoretical basis for the therapeutic effect of plasma in the recovery phase is that immunoglobulin Abs in the plasma of patients recovering from the viral infection may inhibit viremia. To date, in the previous SARS therapy, convalescent plasma given early after the onset of symptoms reduced overall mortality after treatment compared to placebo or no treatment (Mair-Jenkins et al., 2015). For the test of convalescent plasma effect on COVID-19 infection, Zhou et al. found that the SARS-CoV-2 isolated from bronchoalveolar lavage fluid in a severe patient could be neutralized by the serum of several patients (Zhou et al., 2020b). Additionally, another study of Shen et al. showed that improvements in clinical conditions were observed following plasma transfusions, improvements included normalization of body temperature within three days, a decrease in Sequential Organ Failure Assessment score, resolution of ARDS, and decline in viral loads (Shen et al., 2020). During the emerging of COVID-19 infection in China, the National Health Commission of China also called on convalescent patients to donate blood for COVID – 19 therapy. Despite the difficulty in collecting the plasma, convalescent plasma therapy showed great therapeutic potential for the COVID-19 therapy.