Quirks & Quarks

Widespread vaccination should mean the impact of COVID variants 'will be blunted'

‘Under the wrong conditions, I think we haven’t seen all of the tricks [the virus] has up its sleeve yet.’

The more the virus circulates, the more chances it gets to mutate into variants of concern

Hospital staff do an x-ray of the lung of a patient suffering from the coronavirus disease (COVID-19) in Barcelona. (Nacho Doce / Reuters)

As the COVID-19 pandemic evolves, so too has the virus. And vaccination seems to be the most potent tool we have to prevent the emergence of new and potentially more dangerous variants.

Canadian researcher Bronwyn MacInnis, the director of pathogen genomic surveillance at Harvard University and the MIT's Broad Institute, is one of the many scientists around the world who's been watching evolution in action with emerging variants of concern. 

She told Quirks & Quarks host, Bob McDonald, viruses mutate all the time when they make copies of themselves, especially RNA viruses like the SARS-CoV-2 virus, but it's only when those errors give the virus an advantage, enabling it to reproduce even more, that new problematic variants emerge.

The more virus there is, the more chances it gets to mutate, which is why as the pandemic rages around the world, viruses with mutations that allowed them to infect and spread more quickly became dominant.

People carrying the COVID-19 delta variant have 1000 times more virus in their nasal passageway, and the more virus there is, the more chances it gets to mutate. (Dado Ruvic / Reuters)

That's what has apparently happened with the delta variant, which has overtaken much of the world, including Canada. It acquired mutations that lead to infected people carrying it to have up to 1000 times more virus in their nasal passages than the original strain of the COVID virus.

Fortunately higher rates of vaccination reduces the number of people who get infected and thus the number of opportunities the virus has to proliferate and mutate. 

A sign is lit at the front of a bus serving as a mobile vaccination facility run by transit agency Metrolinx and the province of Ontario in Ajax. (Chris Helgren / Reuters)

Produced and written by Sonya Buyting. To hear the interview with Dr. MacInnis, click on the link at the top of the page.


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