Coronavirus: blood plasma of recovered Covid-19 patients could save the very ill, finds US study

Mayo Clinic research finds that treating patients with blood plasma containing a high level of antibodies could reduce mortality rate

Plasma infusion has a long history and was used to treat patients during the 1918 influenza pandemic

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In Beijing, a recovered Covid-19 patient donates plasma on a blood donation bus in February. A study out of the Mayo Clinic in the US has looked at how a plasma infusion rich in specific antibodies may reduce the mortality rate among the very ill. Photo: Xinhua

Published: 8:30pm, 14 Aug 2020Updated: 7:39am, 15 Aug 2020

Treating coronavirus patients in hospital with a high level of antibodies from the blood plasma of recovered patients could greatly reduce mortality, according to a large-scale study run by the Mayo Clinic in the United States.

The study enrolled 35,322 patients treated with such therapy in 2,807 acute care facilities in the US from early April to early July. More than half the enrolments were in the intensive care unit and 27.5 per cent had to breathe with the help of mechanical ventilation at the time of the plasma transfusion.

The study found the early administering of such plasma, called convalescent plasma and donated by recently recovered patients, significantly helped the seriously ill patients

Those who received transfusions – around 200 millilitres or more – within three days of diagnosis had a seven-day death rate of 8.7 per cent while patients who got plasma after four or more days had a mortality rate of 11.9 per cent. The difference is statically significant.

The study also observed a correlation between the level of antibodies in the transfused plasma and mortality.

For 80 patients who received a high level of IgG in plasma the seven-day mortality was 8.9 per cent, whereas for recipients of medium IgG plasma mortality was 11.6 per cent and 13.7 per cent for recipients of low IgG plasma. IgG (Immunoglobulin G) is a common type of antibody.

“The finding of a dose response between antibody levels and reduction in mortality provides strong evidence that specific antibody is the active agent in convalescent plasma for treatment of Covid-19,” the authors wrote.