Ontario’s move to add third booster for seniors backed by study at McMaster in Hamilton


Published August 18, 2021 at 2:47 am


Two McMaster University professors say their research shows why the Ontario government is right to offer third booster doses of COVID-19 vaccines to long-term care and retirement home residents.

Dawn Bowdish, a medical professor at the Hamilton university, and Andrew Costa, who is an associate professor in health research methods, evidence, and impacts at Mac, have been studying how long-term care facility residents have developed immunity after receiving two doses. Both are also researchers with Canada’s Global Nexus for Pandemics and Biological Threats.

There has been enough variance in the immune response that is necessary to make a booster available to long-term care residents and other immunocompromised groups.

“We know now that some long-term care residents — for reasons that may be related to other health conditions or simply to age-related changes in the body — remain vulnerable to future COVID-19 infection even after two vaccine doses,” Bowdish stated in a release.

More than two-thirds of Canada’s COVID-19 deaths have occurred in nursing or long-term care homes.

On Tuesday, the Ontario government said that booster doces will be offered to residents of high-risk congregate settings including long-term care homes, higher-risk licensed retirement homes and First Nations elder care lodges. They will also be offered to transplant recipients, patients with hematological cancers, recipients of an anti-CD20 agent, and 

Costa stated that the good news is that the vaccines are generally effective.

“Over 90 per cent of residents studied create an initial immune response,” he said.

“The critical new science sheds light on what happens after vaccination, and the steps we need to take right now to protect some seniors who remain at risk of infection.”

Costa wrote on his Twitter account on Tuesday that there was “compelling” evidence for a “real vaccine mandate” for healthcare workers, which is not a step the province has not taken.

The unpublished study has been supported by a $5-million COVID-19 Immunity Task Force award from the Canadian Institutes for Health Research, which is part of the federal government.  

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