Canadians shouldn't shop around for vaccines with higher efficacy rates, experts say

The approval of a fourth vaccine in Canadashould not give Canadians the green light tohold off on getting inoculated in order to wait for other doses with higher efficacy rates, medical experts say.

That attitude will end up lengthening the time it takes to get the pandemic under control,saidDr. Peter Juni, scientific director of Ontario's COVID-19 Science Advisory Table.

"If people start to do that, they actually prevent Canadians from moving slowly back to normal," he said.

On Friday, Health Canada approved the use of Johnson & Johnson's COVID-19 vaccine. This is the fourth vaccine approved along with shots from Pfizer-BioNTech, Moderna andAstraZeneca-Oxford.

Differentefficacy rates

Each vaccine has a different efficacy rate.Vaccine efficacy refers to the percentage reduction of disease in a vaccinated group of people compared to an unvaccinated group, under idealconditions.

Pfizer-BioNtech and Modernaboth have been determined by Health Canada to have efficacy rates of around 95per cent. AstraZeneca-Oxford hasan efficacyrate of 62 per cent while Johnson & Johnson hasan efficacy rate of 66.9per cent.

Despite different efficacies, trials have shown that those who did become infected after getting vaccinated experienced only mild illness, said Dr. Sumon Chakrabarti, an infectious disease specialist in Mississauga, Ont.

Of the thousands of participants in trials for the vaccines, not a single person who received a shot died or was hospitalized from COVID-19, he told The Canadian Press.

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As more COVID-19 vaccines become available, a new problem is emerging: people who say they will wait until the shot they prefer is available to get vaccinated. Experts say Canadians should take whatever vaccine is available to avoid prolonging the pandemic.

Dr. Zain Chagla, an infectious diseases physician at St. Joseph's Healthcare Hamilton, said debates over efficacyare going to be part of the challenge ofgetting people vaccinated.

"I think there is obviously something we have to deal with here," he said.

Some of that could have been sparked by confusion over the messaging of theAstraZeneca-Oxford vaccine. Canada's National Advisory Committee on Immunization(NACI) has recommendedagainst using thatvaccine in people aged 65 and older"due to limited information" on itsefficacyin that age group.

In Europe,French and German officials are reversing their initial hesitancy aboutAstraZeneca and arenow urging people to take the vaccine. There arereports that many in Germany have declined the AstraZeneca shot over concerns it may not work as well as others.

Detroit turned down Johnson & Johnson

In Detroit, Mayor Mike Dugganlastweek turned down 6,200 doses of the Johnson & Johnson vaccine,saying he favouredshots from Pfizer and Moderna for now.

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Health Canada's Chief Medical Adviser Dr. Supriya Sharma says the process to approve vaccines in Canada "is based solely on science and evidence and grounded by regulation."

Juni saidlong-term care homes are the only settings where it makes sense to use the highest efficacy vaccines,as residents are at extreme risk.

For most people,"there is no such thing as a bad vaccine," he said.

Junicompared the differences in efficacyto high octaneversus low octanegas. Most engines, he said, just need gas.

"But obviously in the situation we're in right now, if you actually are about to run out of gas, you just take whatever is coming that actually works."

Waiting for a preferred vaccine is just too risky, Chagla said."You don't want to be that person with zero per cent protection going into COVID-19 when you could besomeone with at least 60 to 70 per cent protection, if not higher."

'Just take it'

"You would rather start the clock with some protection rather than no protection," Chagla said.

Given the opportunity to get vaccinated, he offered some blunt advice: "Just take it."

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As a single dose COVID-19 vaccine, the Johnson & Johnson product will be especially helpful for people who sometimes have difficulty accessing health care, says Dr. Lisa Bryski, a retired ER doctor in Winnipeg.

Dr. Susy Hota, medical director for infection prevention and control at University Health Network in Toronto, said for those concerned about different efficacy rates, it's important to know it's not quite an apples-to-apples comparison becausethe clinical trials of vaccines were carried out differently.

Chakrabarti saidthe timing of the trials may have impacted efficacy.Pfizer and Moderna testedtheirproducts when the COVID burden was relatively lower in parts of the world. Johnson & Johnson and AstraZeneca, meanwhile, had their trials later when more transmissible coronavirus variants were spreading at a rapid pace.

What shouldn't be lost, Hota said, isthe overall goalof getting vaccinated which isto protect the most vulnerablefrom getting COVID-19 and to get us out of this pandemic.

'Not justifiable'

That means, with the vaccine rollout being such amassive undertaking including: vaccine availability, vaccineprioritization schemesand vaccine registries, vaccine preference should not be a consideration.

"[If] you have to deal with people wanting to make decisions based on preference. It's just, first of all, not justifiable ...but really not feasible," Hotasaid.

She said peoplejabbed with higher efficacy vaccinesare less likely to suffer from mild symptoms if they were to beinfected, andon an individuallevel, if you don't want to get sick at all, "that might be a better decision for you."

"On a public health sort of population level, I would be very disappointed if people felt that was OK and it wasn't going to cause any harm because wedo need to get to a point to immunize as many people as quickly as possible to make gains in managing the pandemic itself."

Dr. Supriya Sharma, Health Canada's chief medical adviser, said on Friday thatvaccination with a vaccine with66 per centefficacydoes not mean a person will have a 34 per centchance of contracting COVID-19.

"While each of the vaccines Health Canada has authorized has different efficacy numbers, the reality is that you will have a greatly reduced chance of getting COVID-19 with any of the ... vaccines that have been authorized,"Sharma said.

She drove home that point earlier this week, telling CBC's The National that her message to Canadians is that when it's their turn,"you roll up your sleeve" and "take the vaccine that's offered to you.

"And that will help all of us bring down the COVID-19 numbers across Canada, which is the most important thing that we're trying to do."

Join us as experts answer some of your vaccine questions on a specialCBC News NationalTown Hall on Tuesday, March 9. We'll discuss the differences between vaccines, how vaccine passports work and where you might be in the queue. The special starts at 8 p.m. ET onCBC Gemand CBC News Network, and 10 p.m. local time (10:30 p.m. NST) on CBC Television.