狐狸视频

U of T plays leading role in effort to develop COVID-19 treatment from recovered patients' blood plasma

Photo of Jeannie Callum of U of T and Sunnybrook as she leans on a railing with a building in the background
Researchers at more than 40 Canadian hospitals and several universities, including Jeannie Callum of U of T and Sunnybrook, seek to test whether blood plasma from recovered COVID-19 patients can be used as a treatment (photo by Nick Iwanyshyn)

Researchers at the 狐狸视频 are playing a leading role in a national effort to study the efficacy of using blood plasma from recovered COVID-19 patients to treat those who are sick with the disease. 

The joint effort with researchers at more than 40 Canadian hospitals, the Universit茅 de Montr茅al, University of Ottawa, McMaster University and the University of British Columbia seeks to test whether it helps to transfuse plasma 鈥 the pale yellow liquid from whole blood that is rich in antibodies 鈥 from people who have recovered from COVID-19 to patients suffering from the illness. 

Antibodies in what鈥檚 known as 鈥渃onvalescent plasma鈥 could give a boost to the immune system of COVID-19-infected patients to help them fight the disease, says Dr. Jeannie Callum, a professor in the department of laboratory medicine and pathobiology in the Faculty of Medicine and an associate scientist at Sunnybrook Health Sciences Centre.

鈥淎ntibodies are kind of like little forks that stick into the virus and assist your immune system,鈥 Callum says, adding that the body鈥檚 immune system sees the virus attached to the end of the fork and tells macrophages and other immune cells to attack it. 鈥淚t鈥檚 like your immune system is at war and you provided more tanks to fight the enemy.鈥

Doctors in China and other countries have experimented with antibody-rich convalescent plasma to treat COVID-19 patients, Callum notes.  focused on 10 鈥渟evere adult cases鈥 and suggested that a dose of plasma from recovered patients was 鈥渨ell tolerated and could significantly increase or maintain the neutralizing antibodies at a high level.鈥 

The Canadian researchers plan to recruit 1,200 adults and 100 children to participate in separate trials to get a much better idea of whether the technique works and, possibly, answer lingering questions about the novel coronavirus, including why it affects adults differently than children.

Dr. Donald Arnold, a hematologist at McMaster University, Dr. Philippe B茅gin, an immuno-allergist at the Universit茅 de Montr茅al, and Dr. Julia Upton, an assistant professor of pediatrics at U of T and staff physician at the Hospital for Sick Children, are leading the trials. 

Canada鈥檚 blood suppliers, Canadian Blood Services and H茅ma-Qu茅bec, will be managing donations of plasma from those who have recovered from COVID-19.

鈥淭his is the most promising thing I鈥檝e seen in a while,鈥 , a professor of epidemiology in U of T鈥檚 Dalla Lana School of Public Health who is cross-appointed to the Faculty of Medicine. Rather than use convalescent serum in intensive care units, Fisman, who isn鈥檛 involved in the trial, said he could see it being used 鈥渦pstream鈥 to treat patients before their condition worsens. 

Doctors have experimented with convalescent plasma as a potential treatment for other illnesses, including SARS and MERS, which belong to the same coronavirus family. The history of the approach dates back even longer 鈥 to the 1918 Spanish flu pandemic. 

鈥淲e know from the use of the [plasma] product in the 1918 pandemic 鈥 it suggested that the earlier you use the product the more likely it is to change the patient鈥檚 outcome,鈥 Callum says. 

The researchers have chosen to do the trial in an 鈥渋ntermediate鈥 group of patients, meaning those who have been hospitalized but aren鈥檛 so sick that they require intensive care and ventilation. 

鈥淲e鈥檙e hoping to turn it around so that the person doesn鈥檛 need to go on a ventilator or go to the ICU, stays a shorter time in hospital and gets back home,鈥 Callum says. 

Dr. Rulan Parekh, a professor of pediatrics and medicine at U of T and associate chief of clinical research at the Hospital for Sick Children, is part of the SickKids group leading the pediatrics component of the trial. Although children tend to have better outcomes from COVID-19, they may have underlying conditions that put them at greater risk and that differ from those often seen in older adults, like diabetes, Parekh says. 

鈥淓ven though there are few deaths [among children with COVID-19] that have been reported, it鈥檚 more likely that they will have a worsening of their clinical symptoms,鈥 she says. 鈥淲e want to see if the convalescent plasma will improve their respiratory findings.鈥 

Because they expect to have fewer study participants in the pediatric trial, researchers will be able to follow patients over a longer period, Upton says. 

Parekh 鈥 who is also a staff physician in nephrology at the University Health Network 鈥 is also leading a study, with Dr. Dana Devine of UBC and Canadian Blood Services, to follow the donors of convalescent plasma to understand factors that impact immunity.

鈥淲e want to study systematically if the virus-neutralizing antibody [concentration] is associated with outcomes in both children and adults,鈥 Parekh says. 

Even if the clinical trials support the use of blood plasma as a treatment for COVID-19, it wouldn't make the development of a vaccine any less important. The plasma treatment may help COVID-19 patients get better, but a vaccine would help prevent infection in the first place. 鈥淭he vaccine is the holy grail,鈥 Callum says, adding that the plasma treatment could help buy time until one is developed 鈥 a process that experts say may take 12 to 18 months.

For the clinical trial to go forward, Callum says Canadians who have fully recovered from COVID-19 have to be 鈥渞eady to step up to the plate鈥 and donate plasma 鈥 more than once if possible. 鈥淲e鈥檙e going to be wholly dependent on their goodwill,鈥 she says, adding that the procedure is less taxing than donating whole blood. 

Richard Carl, a former COVID-19 patient who recovered at Sunnybrook,  that he already plans to donate. 鈥淭he thought of asking someone to help fix this thing 鈥 I couldn鈥檛 say yes fast enough,鈥 he said.

UTC