Convalescent Plasma as Treatment for COVID-19

laboratory assistant analyzing a blood sample
All 6 patients who received treatment with convalescent plasma subsequently tested negative for SARS-CoV-2.

Six patients with coronavirus disease 2019 (COVID-19) experiencing respiratory failure received convalescent plasma after the first detection of viral shedding; subsequently all 6 patients tested negative for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and 5 patients later died, according to results of a study published in The Journal of Infectious Disease.

The alarming rate of infection of SARS-CoV-2 has affected nearly every country on the globe and has showed an overall a mortality rate of 6.9%. Currently, there is no specific antiviral therapy recommended. There is, however, evidence from previous studies that suggested the use of convalescent plasma transfusions collected from individuals who recovered from SARS-CoV-1 might have help prevent mortality and decrease hospital stay for patients during the 2003 pandemic. Plasma benefits have also been observed to have clinical benefits in patients positive for the Ebola virus, Middle East respiratory syndrome coronavirus, and influenza A H1N1. However there is no previous clinical research to prove the evidence of an improvement on SARS-CoV-2 infection. A study performed at the 2 highest referral hospitals for COVID-19 in the Henan province of China collected data from individuals with SARS-CoV-2 infection to test the use of convalescent plasma for the recovery of COVID-19.

A group of 21 intensive care unit patients with critical COVID-19 were included in the study. As a result of ABO compatibility and limited plasma, 6 of these patients received convalescent plasma treatment; 15 patients were included in the non-plasma control group; the median age of patients were 61.5 and 73 years, respectively. Patients in the 2 groups had similar demographics and clinical features.

After treatment with convalescent plasma infusion there were no immediate adverse effects noted. The mortality in the treatment group was 5 of 6, whereas the mortality in the control group was 14 of 15. However, all patients in the treatment group obtained viral clearance after convalescent plasma transfusions, and 100% (5 of 5) and 21.4% (3 of 14) of patients who died had undetectable SARS-CoV-2 before death in treatment and control groups, respectively (P = .005). Furthermore, the survival period of the plasma treatment group was longer than the control group (P = .029).

Therefore, study authors reported that the convalescent plasma treatment may aid in the clearance of infection for patients with SARS-CoV-2, and results indicated the improvement of viral shedding and thus a longer survival periods for patients with COVID-19. However, plasma infusion does not directly reverse mortality rate in critical care patients and should be introduced earlier. The researchers noted the failure to reduce the mortality rate may be the result of the late transfusion of convalescent plasma, which was administrated on median day 21.5 during viral shedding.

The study had have several limitations including a limited number of patients due to the decreasing rate of infection compared with the initial outbreak of the virus, creating a larger population of patients with mild infection who did not need plasma infusion. Further, the antibody treatment regimen was not standardized, and the study was not randomized. Also, due to the technical limitations of testing, SARS-CoV-2 RNA was not quantitated.

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The study authors concluded that further research is therefore needed to determine factors associated with early phase infusion of plasma in receiving populations to prevent clinical deterioration and reduce mortality rate.


Zeng QL, Yu ZJ, Gou JJ, et al. Effect of convalescent plasma therapy on viral shedding and survival in COVID-19 patients [published online April 29, 2020]. J Infect Dis. doi:10.1093/infdis/jiaa228