From the editorial in the Journal of the America Medical Association accompanying a newly published research article on this possibility:
Shen et al report findings from a preliminary study of 5 severely ill patients with coronavirus disease 2019 (COVID-19) who were treated in the Shenzhen Third People's Hospital, China, using plasma from recovered individuals.1 All patients had severe respiratory failure and were receiving mechanical ventilation; 1 needed extracorporeal membrane oxygenation (ECMO) and 2 had bacterial and/or fungal pneumonia. Four patients without coexisting diseases received convalescent plasma around hospital day 20, and a patient with hypertension and mitral valve insufficiency received the plasma transfusion at day 10. The donor plasma had demonstrable IgG and IgM anti–SARS-CoV-19 antibodies and neutralized the virus in in vitro cultures. Although these patients continued to receive antiviral treatment primarily with lopinavir/ritonavir and interferon, the use of convalescent plasma may have contributed to their recovery because the clinical status of all patients had improvement approximately 1 week after transfusion, as evidenced by normalization of body temperature as well as improvements in Sequential Organ Failure Assessment scores and Pao2/Fio2 ratio. In addition, the patients’ neutralizing antibody titers increased and respiratory samples tested negative for SARS-CoV-2 between 1 and 12 days after transfusion.
Even though the cases in the report by Shen et al are compelling and well-studied, this investigation has important limitations that are characteristic of other “anecdotal” case series. The intervention, administration of convalescent plasma, was not evaluated in a randomized clinical trial, and the outcomes in the treatment group were not compared with outcomes in a control group of patients who did not receive the intervention. Therefore, it is not possible to determine the true clinical effect of this intervention or whether patients might have recovered without this therapy. In addition, patients received numerous other therapies (including antiviral agents and steroids), making it impossible to disentangle the specific contribution of convalescent plasma to the clinical course or outcomes. Moreover, convalescent plasma was administered up to 3 weeks after hospital admission, and it is unclear whether this timing is optimal or if earlier administration might have been associated with different clinical outcomes. Despite these limitations, the study does provide some evidence to support the possibility of evaluating this well-known therapy in more rigorous investigations involving patients with COVID-19 and severe illness.
(Thanks to Dr. David Ozonoff for the pointer.)
