Anti-SARS-CoV-2 virus antibody levels in convalescent plasma of six donors who have recovered from COVID-19.

Background: Anti-SARS-CoV-2 virus antibody levels in convalescent plasma (CP), which may be useful in severe Anti-SARS-CoV-2 virus infections, have been rarely reported. Results: A total of eight donors were considered for enrollment; two of them were excluded because of ineligible routine check. Of the six remaining participants, five samples were tested weakly positive by the IgM ELISA. Meanwhile, high titers of IgG were observed in five samples. The patient treated with CP did not require mechanical ventilation 11 days after plasma transfusion, and was then transferred to a general ward. Conclusions: Our serological findings in convalescent plasma from recovered patients may help facilitate understanding of the SARS-CoV-2 infection and establish CP donor screening protocol in COVID-19 outbreak. Methods: Anti-SARS-CoV-2 antibodies including IgM and IgG were measured by two enzyme-linked immunosorbent assays (ELISA) in convalescent plasma from six donors who have recovered from coronavirus disease 2019 (COVID-19) in Nanjing, China. CP was also utilized for the treatment of one severe COVID-19 patient.