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Canada may find it challenging to reach herd immunity from COVID-19, experts say

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Herd immunity may not be reached in Canada but a return to life similar to that before COVID-19 is possible through immunization, experts say.

Such immunity is achieved when enough people are immune to a virus, either through vaccinations or natural infections or a combination of both.

Prof. Paul Tupper of Simon Fraser University’s mathematics department said herd immunity is unlikely to happen with COVID-19 for a few reasons.

The virus is being transmitted worldwide, which means it is reintroduced in different places across borders and immunity through vaccination and infection doesn’t last permanently. The vaccines don’t seem to be completely effective against some of the new variants, he said.

“So, I think what is more likely to happen is that we end up in a situation like we have with seasonal flu,” Tupper said.

“We have to live with the flu, and I think something similar is going to happen with COVID.”

The level of immunity among the population also changes with the variants, especially the more transmissible strains, he said.

Sarah Otto, a University of British Columbia professor, said the disease’s reproductive rate is hard to pinpoint, which makes it difficult to establish a herd immunity target. Otto is an expert on the mathematical models of pandemic growth and control in the university’s zoology department.

The reproductive rate is the number of additional people infected by a single person with COVID-19, which has also changed because of the variants, she said.

Canada might also fall short of herd immunity because people can still get infected after vaccination, even if they are less likely to develop symptoms, she said.

“We don’t yet know how effective vaccines are at reducing transmission from person to person and that matters a lot,” Otto said.

Vaccinated people are getting fewer infections but those who do can still suffer severe symptoms, she said

“Before the pandemic, we didn’t have working vaccines for coronaviruses, so we don’t know exactly what the outcomes are going to be. It’s very unusual to have a disease with such wildly differing outcomes, with asymptomatic individuals and severely affected long haulers. How are vaccines going to change that mix? We don’t really know why the severe cases are so severe.”

Tupper said public health guidelines will change as more people get vaccinated.

“But the goal of eradicating COVID just does not appear to be realistic.”

Dr. Isaac Bogoch, an infectious disease specialist at the University of Toronto, said vaccines can significantly reduce transmission rates, regardless of whether Canada reaches herd immunity.

“Some communities might have no transmission while other communities, even within the same province, might have some low levels of transmission and it’s all based on vaccine status,” he said.

“But regardless, we will achieve very, very low rates of transmission in our communities because of vaccination.”

Community level immunity is when a virus is not completely eliminated, he said.

“There may be some transmission of COVID-19 but sporadically with small outbreaks or with low levels of transmission, while most people are largely unaffected due to widespread vaccination.”

It had been suggested that herd immunity could be reached when about 70 per cent of the population is vaccinated, but now researchers don’t know what level of protection is required because of the variants.

Otto said there are more questions than answers at this point.

“With every partial answer we get two or three more questions. These are hard and tricky issues and I wish we were less uncertain, but that is the truth of the matter.”

This report by The Canadian Press was first published May 6, 2021.

Hina Alam, The Canadian Press

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Canadian Press NewsAlert: Senior officer who golfed with Vance steps aside from role

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OTTAWA — A senior military officer who recently golfed with former defence chief Jonathan Vance is stepping aside from his role, but not from the Armed Forces overall.

Lt.-Gen. Mike Rouleau says in a statement that he is leaving his position as vice-chief of the defence staff immediately.

He says he will join the Canadian Armed Forces Transition Group, which helps members shift into civilian life.

Rouleau and Royal Canadian Navy commander Vice-Admiral Craig Baines had faced criticism for teeing off with Vance, who is under military police investigation for allegations of sexual misconduct.

More Coming.

This report by The Canadian Press was first published June 14, 2021.

The Canadian Press

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CP NewsAlert: CFL votes to start 2021 season in August after meeting

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The CFL is going ahead with its 2021 season.

The league’s board of governors have voted unanimously in favour of an amended collective bargaining agreement and starting the ’21 campaign Aug. 5.

The CFL did not play in 2020 due to the COVID-19 pandemic.

The league unveiled plans in November for a full 18-game season that was to have started in June but later pushed back the start to August and reduced the number of games to 14.

The Grey Cup game was also pushed back from Nov. 21 to Dec. 12 in Hamilton.

More coming.

The Canadian Press

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