Convalescent Plasma Use in the USA Was Inversely Correlated With COVID-19 Mortality

Researchers tracked the number of units of COVID-19 convalescent plasma that blood banking organizations dispensed to hospitals and correlated that use with hospital admission and mortality data.

Data analysis showed a strong inverse correlation between the use of convalescent plasma therapy and patient mortality. Changes in the number of hospital admissions, the rise of SARS-CoV-2 variants and different ages of patients could not explain these findings.

Key takeaways include:

  • The use of convalescent plasma therapy rose quickly in the summer of 2020 but declined in late 2020 and early 2021 after randomized clinical trials raised doubts about the treatment's efficacy. Despite potential explanations for the negative results, the reports of these studies were sometimes accompanied by editorials and media coverage that reinforced the message of futility.
  • By spring of 2021, mortality rates remained high, with nearly 1,500 daily deaths — despite a drop in the number of new infections. The authors hypothesized that this was correlated with the reduced use of convalescent plasma therapy.
  • To explore this hypothesis, the research team compared the doses of convalescent plasma per patient versus reported COVID-19 deaths per hospital admission from publicly available databases. The comparison of curves showed a trough in deaths per admission coinciding with the peak of COVID-19 convalescent plasma therapy use.
  • Additionally, the subsequent drop in convalescent plasma therapy use was strongly associated with an increase in mortality among patients hospitalized with COVID-19.
  • The authors project that the retreat from using COVID-19 convalescent plasma therapy may have resulted in as many as 29,000 excess deaths from mid-November 2020 to February 2021.