Vaccine hesitancy adding to risk

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This article was published 14/04/2021 (1793 days ago), so information in it may no longer be current.

Worry is growing vaccine hesitancy could affect the population’s ability to reach herd immunity for COVID-19 as the virus circulates indefinitely.

“If we don’t get better coverage in terms of vaccination… I think there’s a pretty good possibility that we’ll essentially never eradicate this virus and it will continue to circulate among the community at non-epidemic levels, but still causing essentially the same kind of diseases,” said Dr. Anand Kumar, a University of Manitoba professor of medicine.

“That may occur in any case, it may circulate at a very low level, even if everybody or most people get immunized, but certainly, if we have a large subset of people not being immunized, it’s going to be much more prominent.”

As of Monday, about 20 per cent of adult Manitobans had received their first COVID-19 vaccine dose.

Kumar said the general estimated percentage of people vaccinated or with natural antibodies to create herd immunity for the initial strain of COVID-19 was around 70 per cent, while the new, more contagious variants have increased that estimate.

“The per cent of people that you need to get herd immunity with any particular type of virus or infection is related to how infectious that virus is. When you get something like B.1.1.7 (variant), which is more infectious and more prone to jump from one person to another, then you need a correspondingly higher number of people to be vaccinated,” Kumar said Tuesday.

Epidemiologist Cynthia Carr said the general rule is 70 to 80 per cent, but warned herd immunity can’t be easily described with a general number.

“It’s looking at natural immunity, vaccine immunity — what do we actually know about the effectiveness of the vaccines in immunity and not just prevention of symptomatic disease and severe outcomes,” Carr said.

It’s unlikely the novel coronavirus will be completely eradicated.

“Eradication needs a vaccine and a treatment, and it’s much easier to eradicate virus that’s only in humans. This virus is in humans and animals,” she said.

“We’re not going to eradicate it, but we’re looking at trying to control it.”

That requires continued investments in vaccines and treatments to reduce clinical severity and increase immunity.

“In many cases, it might mean it’s endemic in this area of the world but not in others, but it could be endemic everywhere but be more like a seasonal flu. Seasonal flu has clinical severity, which is why we invest in vaccines and vaccine campaigns,” she said.

In the provinces, overall, 76.9 per cent of people are very or somewhat willing to receive the COVID-19 vaccine, according to fall 2020 Statistics Canada data.

Angus-Reid polling released Monday suggests 69 per cent of Canadians, including those who’ve already received their first dose, would take the jab if it was available to them. That’s up from just 39 per cent late last September.

Vaccine hesitancy is concerning to Kumar.

“It puts yourself at risk, it puts your loved ones at risk and it puts the general public at risk,” he said.

Carr said reports of blood-clotting following AstraZeneca and Johnson & Johnson doses — both non-replicating viral vector vaccines, as opposed to mRna vaccines like Moderna and Pfizer — show systems are in place globally to alert officials to potential issues.

“Out of the hundreds of millions of (vaccine) doses, we know there have been just over 200 of those overactive blood clotting situations with relation to AstraZeneca and a small number identified with Johnson & Johnson,” she said.

erik.pindera@freepress.mb.ca