The first two COVID-19 patients in Canada to receive plasma transfusions rich in antibodies are showing signs of improvement as the experimental treatment expands to trials in more than a dozen sites in Ontario and Quebec.

The outlook is ``favourable'' for a female patient in Montreal who was the first to receive a transfusion on May 15th.

She has been released from intensive care.

In Toronto, a 78-year-old man who received a second transfusion on May 22nd, is expected to make a full recovery.

The patients are part of a controlled, randomized trial testing whether a transfusion of plasma donated by recovered COVID-19 patients can reduce deaths and speed up recovery.

It's hoped another person's antibodies will help an infected patient battle COVID-19 until their body can develop its own virus-fighting antibodies.

At least five patients had received transfusions by yesterday, with more joining the trial daily.

Researchers hope to study 12,00 participants in about 60 medical centres, 800 of whom will receive transfusions while 400 will be part of a control group that gets no transfusion.

The trial will be expanded to at least 20 hospitals by the weekend, most of them in Ontario but including a handful in Quebec, and three in New York City.