COVID-19 and convalescent plasma

The clinical trial will assess if convalescent plasma from donors who have recovered from COVID-19 and are vaccinated against the disease may be an effective treatment for patients who are immunocompromised and hospitalized with severe illness. While COVID-19 vaccines are widely available for most age groups, someone who is immunocompromised may not have a strong enough immune response after vaccination to protect them from becoming seriously ill if infected.  

In 2020, we supported similar clinical trials and the results showed convalescent plasma with a high level of antibodies against COVID-19 may benefit patients with immunodeficiency. The 2022 trial will further explore this. It will be an important contribution to research on a global scale that could help more patients in Canada and around the world.  

Canadian Blood Services is responsible for supplying convalescent plasma to all physicians caring for patients in Canada within the context of the clinical trial, under the authorization of Health Canada. Hema-Quebec will distribute convalescent plasma we collect to participating hospitals in Quebec.

As the national blood operator, we have the expertise and the infrastructure necessary to safely collect, prepare and distribute convalescent plasma for use in clinical trials.

Well-designed clinical trials, like the one we were involved with, help provide the information necessary to prove whether convalescent plasma may be an effective treatment for the most vulnerable patients here in Canada and around the world.

The trial we are supporting is called Clinical Trial for Convalescent Plasma for COVID-19: Randomized, Embedded, Multifactorial Adaptive Platform Trial for Community-Acquired Pneumonia (REMAP-CAP). Bacterial and viral infections, including COVID-19, are responsible for most cases of community-acquired pneumonia. 

More than 300 sites in 21 countries, including Canada, are participating in REMAP-CAP. Well-designed clinical trials, like this one, help provide the information necessary to prove whether convalescent plasma may be effective treatment option for patients who are immunocompromised and experiencing severe illness caused by COVID-19.  

To learn more about the trial, visit remapcap.org.

While past studies we contributed convalescent plasma to, and others internationally, did not demonstrate sufficient benefit for the patients enrolled, the results did show COVID-19 convalescent plasma contains antibodies of different types, amounts and functions and that these antibodies can vary significantly from one donor to another. Therefore, there may be potential benefit from plasma with more antibodies compared to plasma with fewer antibodies.  

The timing of how quickly and frequently convalescent plasma is administered may also be a factor, as some studies have shown repeated transfusions earlier in patient care could lead to improved effects.  

And data from one of the studies we supported (REMAP-CAP) suggested that patients who were immunocompromised may benefit from convalescent plasma.    

The research team for this study (REMAP-CAP) is now investigating if plasma with higher levels of COVID-19 antibodies (convalescent plasma from donors who have recovered from and are vaccinated against the disease) transfused sooner could help patients who are immunocompromised recover from serious illness resulting from infection. Even if fully vaccinated for COVID-19, someone who is immunocompromised may not have a strong enough immune response after vaccination to protect them.

Canadian Blood Services will resume collecting convalescent plasma in November 2022 for use at all participating hospitals in Canada. We will continue collecting convalescent plasma donations until the clinical trial investigators in Canada confirm they have the supply needed to complete their research. 

Generally, clinical trial results are known after a trial is complete and the research team has been able to analyze the full dataset from the trial. It can take several months before a research team is ready to publish the results. 

The clinical trial needs to be completed first, so we have evidence that this therapy actually works. Internationally, researchers continue to develop and investigate various options to treat, prevent or cure COVID-19. At this time, it is too early to say what could happen or what our role may be longer term.

There are many reasons someone is or may become immunocompromised. For example: 

• Cancer treatment
• Having a stem cell transplant (within the last two years)
• Receiving chimeric antigen receptor (CAR)-T-cell therapy (a treatment to help the immune system attach to and kill cancer cells)
• An organ transplant requiring medication that suppresses the immune system
• Moderate or severe primary immunodeficiency (e.g., DiGeorge syndrome, Wiskott-Aldrich syndrome)
• Advanced or untreated HIV infection
• Active treatment with high-dose corticosteroids or other medications that can suppress immune response

Patient participation in the trial will be determined by their treating physician in consultation with the patient and according to the clinical trial protocol.

Yes. Since 2020, data collected on the use of COVID-19 convalescent plasma through various studies around the world — some of which Canadian Blood Service participated in — has shown it is safe for patients to receive. Today’s research is now focused on how and when COVID-19 convalescent plasma is administered and whether it may be an effective treatment for some patient populations (e.g., patients who are immunocompromised).