University of Alberta research finds vaccines played key role in 'domesticating' virus

The wolf is still at the door — the study warns against letting down public medicine’s guard against viruses that reach endemic stage.

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Government officials seeking to minimize the importance of COVID vaccines are being schooled by a new paper out of the University of Alberta, researchers say.

Research from Ryley McClelland, a PhD candidate in virology, and his colleagues shows vaccines played a key role in reducing the pathogenicity — the ability of an organism to cause disease — of SARS-CoV-2 by speeding up the domestication process, and helping it adapt to humans without killing.

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“The Alberta government has essentially downplayed the benefits of vaccines, so we essentially have to do it for them in science,” said McClelland, who is a member of the Smith’s Landing First Nation in the Northwest Territories.

The project used the province’s own COVID-19 data from March 7, 2020, to Nov. 21, 2022, a period during which Alberta confirmed 618,030 cumulative COVID-19 cases and 5,177 deaths due to the virus.

The daily number of intensive care unit (ICU) admissions or deaths, divided by the number of hospitalized cases, served as an approximation of COVID-19 severity within a one-week to one-month time frame of hospital admission.

McClelland used these calculations of severity as part of the study showing SARS-CoV-2 variants emerged due to adaptation in humans, shifting it toward an endemic seasonal virus instead of a pandemic.

“We have termed this process ‘virus domestication,’” McClelland said, noting domestication doesn’t mean SARS-CoV-2 is harmless, any more than a domesticated wolf would be harmless.

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After the World Health Organization declared a pandemic on March 11, 2020, there was an initial rise in daily infections, hospitalizations and deaths, which all decreased with the implementation of COVID-19 health protection measures.

Following the reopening of schools for in-class instruction after week 28 of the pandemic, there was another wave of cases, hospitalizations and deaths, the study notes.

“Consistent with the domestication model, we observed a decrease in daily deaths whereas daily cases increased to their highest levels with the peak of Omicron BA1 prevalence,” McClelland stated, noting a considerable reduction in ICU admissions versus hospitalizations with the arrival of variants Delta and then Omicron, in particular.

Overall, the study suggests, SARS-CoV-2 has become more infectious and less virulent through viral domestication.

ICU hospitalization surrogates and plaque sizes decreased by about ten-fold and 17-fold, respectively, with Omicron as compared to the Delta variants. (Plaques are regions of cell destruction caused by an agent such as a virus.)

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McClelland said the findings highlight the importance of SARS-CoV-2 vaccination, and should help inform public policy on the highest probability outcomes.

“This domestication process doesn’t mean it became safer. If anything, this has shown the importance of vaccinations overall. (The vaccines) sped up the domestication process of the virus, and reduced its pathogenicity,” he said, adding that even asymptomatic infection doesn’t mean it’s harmless.

The wolf is still at the door — the study warns that public medicine must keep up its guard against viruses that reach endemic stage.

“This shows we need to keep vaccinating for SARS-CoV-2,” McClelland said, noting that other research has concluded micro-infarctions caused by the virus blocks blood vessels, which could cause severe neurological effects.

“There are significant burdens to global mortality,” he added, citing another domesticated killer. “RSV is the second leading cause of infant mortality worldwide.”

Researchers on the study included Yi-Chan James Lin, Tyce N. Culp, Ryan Noyc, David Evans, Tom C. Hobman and Vanessa Meier-Stephenson. Senior author on the project was David J. Marchant.

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