COVID-19 convalescent plasma shows a trend toward an early mortality benefit compared with hospitalized patients who receive standard treatment, according to research published in the British Journal of Haematology.

Convalescent plasma aims to reduce disease severity by passively transferring antibodies to neutralize the virus. The authors retrospectively compared 263 hospitalized patients who received COVID-19 convalescent plasma to 263 matched controls who received standard treatment at 1 academic health system. The primary outcome measured was 28-day mortality, with evaluations at 7 and 14 days.

Patients who received convalescent plasma had a longer hospital stay than controls, but a decreased risk of death at 7 and 14 days. The 7-day adjusted mortality was significantly better for patients who received convalescent plasma than controls (9.13% vs 19.77%, P <.001). The plasma treatment group also had a significant reduction in 14-day mortality compared to the control group (14.83% vs 23.57%, P =.01).

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Patients who received plasma within 3 days of arrival had a significant time to improvement in oxygen device category (3 days vs 6 days in the control group, P =.02).  However, there was no significant difference in mortality between both groups at 28 days. The 28-day mortality for patients receiving convalescent plasma was 25.48% compared with 27% in the control group (P =.06).

“Convalescent plasma may provide clinical benefit when it contains high IgG antibody titres and when given early in the course of disease,” the study authors wrote.

The study had some limitations. The antibody titres of the transfused plasma were unknown. Patient comorbidities were also not evaluated, and the authors suggested that future studies or analyses of these data should include evaluating pre-existing comorbidities.

Future analyses will look at the hospital course of patients to evaluate why the convalescent plasma did not benefit 28-day mortality.

Disclosures: Some authors have declared affiliations with or received grant support from the pharmaceutical industry. Please refer to the original study for a full list of disclosures.


Shenoy AG, Hettinger AZ, Fernandez SJ, Blumenthal J, Baez V. Early mortality benefit with COVID-19 convalescent plasma: a matched control study. Br J Haematol. 2021;10.1111/bjh.17272. Published online January 22, 2021. doi:10.1111/bjh.17272