N.B.'s use of 'confounding and weird' definitions of vaccine protection causing confusion: virologist

For the last two weeks, the rate of death has been higher for New Brunswickers "protected" from COVID-19 than those who are "unprotected," according to the province's weekly reports.

But while the numbers appear to paint a troubling picture, it's not an accurate one, says Raywat Deonandan, a global-health epidemiologist and an associate professor at the University of Ottawa.

He said the problem is the way the provincial government calculates the category, which makes it appear as if those who have been vaccinated are more likely to die — which is far from the case.

"I think this is a master class in poor communication," he said.

The province's weekly COVID-19 report lumps someone with two doses and a booster — albeit more than six months ago — in with someone who hasn't had a single shot.

While that first person's immunity may have waned, it's certainly a lot better than someone who hasn't had any vaccination, said Deonandan.

Protected vs. unprotected COVID death rates per 100,000

He said the problem lies with how the province defines "protected" and "unprotected."

"Protected" is defined as boosted or fully vaccinated less than six months, while "unprotected" refers to being fully vaccinated for more than six months, being partially vaccinated or being unvaccinated.

According to the Department of Health, only 53 per cent of New Brunswickers are considered "protected."

But Deonandan said everywhere in Canada, including New Brunswick, vaccinated people far outnumber unvaccinated people, and that the death rate of unvaccinated group is much higher. In fact, international statistics show the death rate is three to four times higher for unvaccinated people, he said.

There's also another problem with New Brunswick's numbers, said Deonandan.

By grouping those who are up to date with their shots and boosters in one category and everyone else in the other, it "confounds" the numbers because a variety of risk factors associated with age are unevenly distributed between the groups being compared.

Those most likely to be fully vaccinated and boosted are older, said Deonandan. That's also the group most likely to die.

"People above 70 are going to die. They're always dying. People above 70 are also more likely to be vaccinated because they're more vulnerable to COVID. So they're going to die at a high rate … so that gives you the illusion that vaccination is associated with higher death rates."

Deonandan said the opposite is true.

"Every jurisdiction in the world has seen profoundly lesser death rates amongst the vaccinated versus the unvaccinated. Everywhere. New Brunswick is no different than anywhere else.

"So this is a mathematical illusion caused by confounding and weird definitions of 'protected' and 'unprotected.'"

The way New Brunswick calculates COVID-19 deaths is misleading and could send a false message about the effectiveness of vaccination, said Colin Furness, an infection control epidemiologist and an assistant professor with the faculty of information at the University of Toronto.

The "protected" and "unprotected" groups are two different populations, said Furness, and those differences become very important when the prevalence of COVID-19 increases.

"People who are not vaccinated tend to be younger and healthier. Some of them drive around in convoys, and that's very different from vaccinated people."

The vaccinated group is generally more health-conscious and concerned about COVID-19. It would also include older, more vulnerable people.

"Those are people for whom vaccination becomes more important."

Furness said the groups also respond differently to a higher prevalence of COVID-19.

When COVID levels are low, people are less likely to be exposed to it. And because the vaccinated population is generally more vigilant about avoiding it, they are "disproportionately more safe."

But when there's more COVID around, as there has been in recent months in New Brunswick, it's more difficult to avoid.

And when older, more vulnerable people — who are more likely to be vaccinated — get sick and end up in the ICU, they are far more likely to end up dying from it, said Furness.

He said compared the data to what happened in the first six months of vaccination in the United Kingdom, when people getting vaccinated were dying at a much higher rate than those who were not vaccinated.

"That's because vaccination was prioritized for those who were most frail, and vaccination alone can only do so much to protect people. Those unvaccinated were simply less likely to die at all because they were younger and healthier, regardless of vax status."

Message remains the same

Furness said it's important to note that the numbers still clearly support the importance of getting vaccinated. In New Brunswick, for example, you're twice as likely to end up in the ICU if you're not vaccinated.

And that, he said, can be "life-altering."

"You may not die, but your lungs may never really fully recover. Ending up in the ICU is really bad in terms of long-term health outcomes."

Because most unvaccinated people are younger, Furness said they're usually able to survive the disease.

Deonandan worries that the "mathematical illusion" that New Brunswick has created around death rates could be falsely interpreted by those spreading anti-vaccine messages.

"We're in a new era where these kinds of reports have to be written with more careful attention to the ways in which these data are going to be interpreted," said Deonandan.

"In fact, there's a new study out suggesting that these COVID vaccines might be the most effective biotechnological public health intervention in the history of human civilization. In a sense, they have saved more lives than anything else we've ever invented."

According to a study published in the Lancet, vaccines have averted nearly 20 million deaths worldwide.

'Dialling down risky behaviours'

Furness said the numbers also prove what experts have been saying for a long time — that "vaccination on its own is not going to be adequate to protect people who are particularly vulnerable" when there is a lot of COVID-19 around.

"So you need to have a combination of interventions in order to make COVID not prevalent, then being vaccinated will be a lot more helpful."

That includes masking, particularly around vulnerable populations, like those in hospital and nursing homes, paying attention to indoor air quality, and "diallling down risky behaviours, not sharing indoor air with others."

If we did all of those things, Furness said "COVID prevalence would drop and then death rates would drop. But vaccination underpins all of this."

Furness said a lot of hope was put into the vaccines but they didn't end up being as "durable" as experts had hoped.

"I was really hoping in this pandemic that you'd get vaccinated twice and you'd be done. In actual fact, in order to protect all of us, we need to get vaccinated a little bit more frequently," he said.

"We need better vaccines, there's no question."

Furness said scientists are working on a number of advancements. One is an Omicron-specific vaccine that will be available in the fall.

He said they're also developing a nasal spray that induces a strong immune response in the nose, which could provide better protection against getting infected in the first place.

'The Holy Grail'

"The other one, which I'm very excited about, is the idea of a pan-coronavirus vaccine," said Furness.

He said scientists are working to develop a vaccine that isn't vulnerable to changes in the coronavirus's spike protein and mutations that reduce immunity.

A vaccine that targets a virus regardless of mutations would have implications beyond the coronavirus, said Furness. It could also cure some of the common colds,and other forms of SARS.

"It would prevent other coronaviruses in the future from causing these same sorts of problems. So to me, that's the Holy Grail."

The research is cause for optimism, said Furness, but it could be several years away.

"I don't want to get people's hopes up for a quick fix."

No response from Health Department

Asked about the significance of the death rates on Tuesday, Dr. Jennifer Russell, the province's chief medical officer of health, said she wanted to discuss the issue with her team to get a "better sense" of it.

"I don't think it's black and white," she said.

Her department was asked for an explanation again Wednesday morning but didn't provide a response by publication time.