Drop in Use of Convalescent Plasma Linked With Higher COVID-19 Mortality Rate

A recent study published in the journal eLife has discovered that a slowdown in the use of convalescent plasma in United States hospitals to treat COVID-19 led to a higher rate of mortality during a critical period of the ongoing pandemic.

The study was conducted by investigators from the Johns Hopkins Bloomberg School of Public Health, in collaboration with Michigan State University and the Mayo Clinic.

“A strong inverse correlation between [convalescent plasma] use and mortality per admission in the USA provides population level evidence consistent with the notion that [convalescent plasma] reduces mortality in COVID-19 and suggests that the recent decline in usage could have resulted in excess deaths,” the authors wrote.

For the study, the team of investigators compared the number of units of plasma distributed to hospitals inside the US from blood banks, on a per patient basis, to the number of reported COVID-19 deaths per hospital admission across the country.

Findings showed that convalescent plasma use peaked during December and January of 2021, and after reports of negative results in clinical trials, they fell sharply and deaths rose.

The investigators then created a model to fit the data. The model showed that COVID-19 case fatality rate decreased by 1.8 percentage points for every 10-percentage point increase in the rate of plasma use. 

The model found that 29,018 deaths could have been avoided between November and February of 2021 if peak use in October of 2020 never changed. Additionally, the use of convalescent plasma on the whole was associated with 95,000 fewer deaths through early March of 2021.

"Clinical trials of convalescent plasma use in COVID-19 have had mixed results, but other studies, including this one, have been consistent with the idea that it does reduce mortality," Arturo Casadevall, senior author on the study said. "We hope that physicians, policymakers, and regulators will consider the totality of the available evidence, including our findings, when making decisions about convalescent plasma use in individual COVID-19 patients.”