Why we can’t expect a COVID-19 vaccine to save us

Ten burning questions answered on the most elusive virus scientists have ever seen


Most experts agree a vaccine for COVID-19 will be available sooner rather than later. But as new case numbers surge and a summer of reopening starts to give way to renewed restrictions and fall fatigue, the urgency to find an antidote for the pandemic of our times is rising.

The chase for a cure is on, but the most promising human trials so far have had to be paused. Scientists knew taming this virus would be trickier than anything they’ve encountered before.

But the mad scramble to get on the other side of this pandemic is raising ethical and political issues as well.

1. Where’s the COVID-19 vaccine at?

It’s still very much a moving target. We’re nine months into the trajectory of a disease that most experts say will be with us for two years. 

The optimistic projection is that a vaccine will be ready by January. There are some 200 trials worldwide, and a handful of those have entered stage 3 human trials. But those won’t be completed until 2022 or 2023. And two of the most promising research studies have had to be “paused” over adverse side effects. 

The best-case scenario – at least in the short term – says David N. Fisman, professor of epidemiology at the University of Toronto’s Dalla Lana School of Public Health, is a vaccine that’s effective “in some way” by spring or summer. 

The big problem from a scientific point of view, says Fisman, is that the most promising vaccines so far are better at prventing disease than infection.  “The people who are getting sick and dying [from COVID-19] are also the folks who usually have the weakest responses to vaccines.” 

Whatever the projections, the development of a vaccine to treat (if not end) the virus will have to be sooner rather than later. We could be dealing with a different strain months from now.

And the simple logistics are such that it will be some six months after a vaccine is developed before it can be mass-produced and starts reaching the general population.

Adding to the complexity is that vaccines showing the most promise have to be stored in temperatures of between -20 to -80 degrees Celsius. That will make transportation – not to mention distribution in developing countries – a challenge. 

2. Who will be the first in line for a vaccine?

The answer is not so straightforward. The conventional wisdom is that those at most risk (health-care workers and people over 65) would be prioritized. 

But there’s growing research to suggest otherwise. 

According to yet-to-be-published modelling conducted by researchers at the University of Waterloo, vaccinating those more likely to spread the virus (ie: young people, in particular between the ages of 15 and 19) gives us a better chance of reaching enough immunity in the general population to avoid high mortality. But that’s only if a vaccine becomes available later in the pandemic (July 2021). The scenario is flipped if a vaccine becomes available earlier (January 2021).

Closer to home there’s also the politics to consider. The Trudeau government has signed on to World Health Organization (WHO) efforts to prioritize the distribution of a vaccine (when it is finalized) in developing countries.

Canada’s participation in the effort gives it the option of purchasing another 15 million doses of a vaccine. But where we’ll be in the pecking order should the U.S., China or Russia develop a vaccine first is an open question. None of those countries have signed on to the WHO effort.

Bob Hilscher / Getty Images

People wait in line for a COVID-19 test at the Birchmount COVID-19 Assessment Centre at 3030 Birchmount Road in Scarborough.

3. How effective will a vaccine be?

It’s the trillion-dollar question. 

It’s not known to what extent the two trials that were paused recently – reportedly due to inflammation around the spine in one subject – will set efforts back. 

“But clearly scientists are seeing something they did not expect,” says Thomas Tenkate, associate professor at Ryerson’s University’s School of Occupational and Public Health. 

It’s not unusual for trials to be paused over side effects, experts agree. But the political pressure to develop a vaccine for the coronavirus is unlike anything we’ve ever seen before. Approval processes have been fast-tracked. In Canada, Health Canada has started its own “rolling reviews” of candidate vaccines.

But to what extent the scramble to find a cure may compromise safety and push a vaccine into the market before it’s ready is one of the many ethical issues that have been raised. 

The numbers involved in the largest trials (some 30,000 to 60,000 people) far exceed the 3,000 accepted by the U.S. Food and Drug Administration FDA.

But experts caution that adverse side effects may emerge among the hundreds of millions of people that are expected to get a COVID vaccine.

At what point, for example, would those side effects become unacceptable? The bar set by the FDA, which other countries take their cue from, is that a COVID-19 vaccine would have to protect at least 50 per cent of people vaccinated to be considered “efficacious.”

4. Do Canadians believe a vaccine will be safe?

Transparency is key to developing public trust in a vaccine. But recent polling by Angus Reid suggests that Canadians are wary of safety issues. Fewer than half surveyed, some 39 per cent, said they would seek to be vaccinated as soon as a vaccine became available.

That’s lower than in the U.S. where some 50 per cent said they’d line up for a vaccine.  

The recent drop in Canada is most pronounced in Alberta and Quebec. Those also happen to be the two provinces with the highest per capita cases of COVID-19 infection in the country. And where, not so coincidentally, anti-mask and anti-vaxxer movements are messing with the public safety messaging.

In Alberta, the proportion of residents considering vaccination as soon as possible has dropped 13 points since July. In Quebec, the number has declined by 11 percentage points. But anti-lockdown types and anti-vaxxers are not the only ones moving the needle on public opinion. Overall, seven in 10 Canadians (69 per cent) said they were concerned about safety issues. 

5. Will a vaccine be a cure-all?

The short answer is no. While natural immunity in those who have had other coronaviruses like SARS and MERS can last up to five or six years, the window for COVID-19 is much narrower.

Some research suggests that a vaccine may only make people immune from the virus for some 18 months, according to a recent report published in the British medical journal the Lancet. Other research suggests that the number is closer to six months.

As the Lancet article points out, “There is little knowledge of post-infection immunity to SARS-CoV-2, and the biological and genetic factors responsible for the broad spectrum of disease severity remain unclear.” 

Understanding the effects of a possible vaccine on children and pregnant women also remains a gap in the current research. None of the trials currently underway has subjects younger than 18. Pregnant women have also not been part of any human trials. 

Freer Law / Getty Images

6. What are the costs involved?

The Trudeau government says a vaccine will be distributed free in Canada. But the international feeding frenzy to procure a vaccine is already resembling the supply issues we saw with personal protective equipment during the early days of the pandemic with governments placing their bets on a host of vaccine candidates.

So far, the feds have dropped $1 billion on contracts to buy millions of doses of a vaccine from half a dozen manufacturers. 

Despite the international goodwill to develop a vaccine, there is still a lot of money to be made for those who hit the finish line first. And there’s no telling at this point how that may affect distribution. 

7. Is herd immunity even an option?

There’s been renewed talk of herd immunity. That’s the idea that allowing the virus to make its way through the general population would eventually see enough people develop an immunity for it to go away.

The proportion of the population that has to be infected for herd immunity to occur has been estimated at 75 per cent. Others have put that number at 50 per cent. 

The death tolls turned out to be a disaster in countries where it was tried early on.

But as the pandemic becomes more drawn out, calls to end lockdowns and let the disease run its course have gotten louder.

The World Health Organization calls that option unethical. Tim Sly, professor emeritus in epidemiology at Ryerson, calls the idea “lunacy.” 

“The costs in terms of the huge numbers of deaths, and especially the collapse of medical and hospital services, is unacceptable,” he says.

Most health experts agree that any attempt to loosen COVID restrictions risks setting off a larger second wave. 

8. What does the recent surge in cases in Ontario tell us?

Clearly we have testing issues in the province that are hindering efforts to track and trace the disease. COVID fatigue is also setting in. We’re less afraid of the virus than we were in March, which is leading to a level of complacency. 

But compared to the rest of the planet, we’re faring better than most, says Fisman. “People look at what is, but as an epidemiologist I look at what isn’t,” says Fisman. 

While the raw numbers are higher than they’ve ever been in the province, Fisman points out that the rise in “lagging indicators” – deaths and hospitalizations associated with the virus – is more “linear” than the exponential growth we were seeing early in the pandemic. 

What’s also clearer is that while we can slow down the spread of the virus, stopping it completely is trickier. Some would say it’s impossible given its ability to spread asymptomatically.

Schools, for example, are emerging hotspots, making up a growing number (and percentage) of total new daily cases in the province. “It’s the tip of the iceberg,” says Anna Banerji, an infectious disease specialist at the University of Toronto. She says she sees cases every day of children who are displaying flu-like symptoms that can only be COVID-19, but falsely test negative for the virus anyway. 

Andrei Naumenka / Getty Images

9. At what point will it be time to consider another lockdown?

Several countries in the European Union are considering a second lockdown as another wave of the virus flows over the continent.

Germany, Italy and France are reporting anywhere from 20,000 to 50,000 new coronavirus cases per day. The U.S. is reporting 80,000 new cases every day. By comparison, Canada is seeing about 2,300 new cases – although the populations of France, Italy and Germany are roughly twice Canada’s.

It’s at the point in those countries where not to lock down risks losing control over the virus. It’s unlikely it will reach that point in Ontario. We know what seems to work – keeping people apart. But not everyone can do that forever. 

10. What does a post-vaccine world look like?

If only we had a crystal ball. What we do know is that the coronavirus is highly mutable. That means it could remain virulent for some time even with a vaccine. 

On the other hand, it could drift through the population, Fisman says, becoming like any other seasonal flu for which we show up at the drug store every year to be vaccinated. 

The good news is that COVID-19 is going to end – eventually. The bad news is we don’t know when. Either way, it’s going to be a chess game to stay ahead of the virus. 

For more, listen to a podcast interview with Tim Sly, professor emeritus in epidemiology at Ryerson University, about how COVID-19 vaccine development is progressing:

@enzodimatteo

Comments (1)

  • Frank Sterle Jr. October 29, 2020 04:46 PM

    I hope a vaccine somehow makes it out and becomes available to the common citizen sooner than anticipated.
    I typically receive the annual influenza vaccination every fall, but for the last few years I’ve specifically asked for a placebo … to which I receive a serious look by the injection administer, who’s clearly not amused by my attempt at humour on this otherwise serious topic.

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