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.