The plasma of patients healed, a weapon against the coronavirus?

Le plasma de patients guéris, une arme contre le coronavirus?

Illustration of the coronavirus

April 9, 2020

Updated on April 10, 2020 to 0h15

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The plasma of patients healed, a weapon against the coronavirus?

Jean-Benoit Legault

The canadian Press

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MONTREAL — The largest clinical study to date on the use of plasma convalescent in the fight against the coronavirus will be carried out in Canada and several institutions in quebec will participate.

The treatment will be studied in the context of a large clinical trial including a fifty centres in Canada, including a dozen in Quebec.

Scientists at the CHU Sainte-Justine, Centre de recherche du Centre hospitalier de l’université de Montréal, the jewish general Hospital, Héma-Québec and several other hospitals in the province will be as well part.

“It is a therapy to treat the disease, explained one of the leaders of the study, dr. Philippe Bégin at the CHU Sainte-Justine. We speak of passive immunization, with a vaccine we are talking about active immunization.”

Passive immunization involves transfusing plasma from patients cured of the COVID-19 – the plasma-convalescent – in patients in early disease in order to transfer protective antibodies in the hope of limiting the severity of their symptoms.

The plasma is the liquid portion of the blood that contains the antibodies that protect against disease.

“It is like the proverb ‘give a fish, you feed someone for a day, teach a man to fish, you feed someone for always’, was illustrated by dr. Bégin. The vaccine teaches you to fish. You give the widget for which you want to be immunized, the body starts to produce its own antibodies, and he will make them for ever.

“But then, we don’t have the time, because first of all it is not yet known to fish, so you can’t really teach it. So the idea is that we just give the antibodies produced by someone else.”

Anecdotal evidence

The approach was used before the advent of vaccines, during major epidemics, and this is not the first time that we are considering using the plasma from convalescent to combat the COVID-19. But the “evidence” that point towards effectiveness of the treatment remain for the moment anecdotal and of poor scientific quality.

The light therefore remains to be done on the matter, and it is this that will make the quebec researchers and their colleagues at McMaster University, hospital toronto Sunnybrook and SickKids Hospital in Toronto.

“We are a little blind, has admitted dr. Bégin. We don’t have tons of studies that tell us that it takes a particular type of antibody, or such a quantity of plasma.”

The best way to see more clearly is to collect the most quickly as possible the largest possible amount of data, he added.

“We want to go fast, and the best way to go fast is to be several to do the same protocol to put all the data together, he explained. We have colleagues from other countries who are interested and with which we share our protocols so that they are loaded in the same protocol, and even there we could put our data all together and go even faster to acquire the data.”

It is about a month after the end of the disease that the antibody levels are the highest, and it is at this point that we can proceed with a levy. As the pandemic sweeping across Quebec for a few weeks, the number of potential donors – even if it will increase – remains for the moment limited.

The researchers therefore decided that the plasma convalescent available will be restricted to patients infected by the disease. It is not impossible, later on, whether it is offered as a preventive measure, for example health workers working closely with the virus.

Approximately 1200 patients will be recruited in Quebec, including 800 who will receive the plasma convalescent. The study should last approximately three months.

Héma-Québec will be responsible for the collection of plasma in patients healed.

Le Soleil

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