The COVID-19 vaccines are starting to roll in. Should the oldest get them first?

When COVID-19 vaccines started to trickle into Canada in December, health officials had to decide who should get them first. Given the scarcity of doses, the answer was easy: residents of long-term care and retirement homes.

These vulnerable seniors made up 81 per cent of the deaths in Canada in the first wave of the pandemic. If there was only a smattering of available jabs, it made sense to deliver them to the people at by far the greatest risk of death.

The question facing public-health officials and political leaders now is whether focusing on vaccinating those oldest and most at-risk from COVID-19, rather than those most likely to spread it, is still the best strategy.

Thanks to a vaccine rollout that began in LTC homes, deaths there have dropped dramatically. In the second week of January, Quebec recorded 131 LTC deaths from COVID-19. Last week, the number was five. It’s the same story in Ontario, which has recorded just nine virus-related LTC deaths since March 1.

This counts as a big change in Canada’s pandemic, and a huge improvement. It’s proof the country made the right choice when it allocated the first, scarce doses of vaccine.

But this week the delivery of vaccines to Canada will go from first gear to something approaching the posted speed limit on a country highway. More than a million doses will be arriving weekly between now and the end of May, a number that will increase as production of more recently approved vaccines ramps up.

Other factors have changed since Canada devised its rollout strategy, too. Most notably, we now have a better idea of how effective the vaccines are.

Early data from Israel show that the Pfizer jab not only reduces the likelihood and intensity of infections, but also cuts down on transmission. A study released Monday in the United States shows that the AstraZeneca vaccine is highly effective against COVID-19′s worst outcomes.

At the same time, however, there is growing concern about variants of the COVID-19 virus that are more transmissible. That appears to be one of the reasons why, in much of the country, case counts are on the rise again.

Given these facts, what is the fastest and most efficient way to use vaccines to win the race against the variants? Should priority for shots continue to go to people most at risk, which means focusing on the oldest Canadians? Or should priority switch to those most likely to spread the disease?

Those are two very different groups. People under 60 make up 80 per cent of Canada’s recorded infections to date, but only 4.1 per cent of COVID-19 deaths.

People aged 60 and up account for just 20 per cent of the infected, but 96 per cent of the deaths.

Choosing whom to prioritize is a long-standing and complex debate among scientists. One recent study in the journal Science Advances suggested it is best to target vulnerable populations if vaccine effectiveness is low. But when vaccines are highly effective and readily available, it found that the more efficient strategy is to concentrate on vaccinating high-transmission groups in order to more quickly achieve herd immunity – thereby protecting unvaccinated people of all ages and vulnerability.

Right now, Canada’s strategy continues to focus on rolling out vaccines by descending order of age, with additional priority for health care providers, front-line workers, Indigenous Canadians and people with pre-existing conditions.

The younger age groups most likely to carry and transmit the disease will be vaccinated last.

That’s not an unreasonable strategy. If all goes well, most Canadians will be vaccinated by midsummer anyway. And many people would be alarmed to see healthy 25-year-olds getting jabbed while someone in their 50s was still waiting their turn.

But other places are at least edging in that direction. U.S. President Joe Biden wants the states to open vaccinations to every American over 18 by May 1. In some states, such as Nevada, everyone over 16 is already eligible.

Would it make sense for Canada to loosen or modify the system of age priority? It’s a tough call that would have to take account of the speed of our vaccine deliveries, which are well below the U.S. pace.

But in a crisis, all options have to be considered. The places that defeat the pandemic the soonest will be those that get the most bang out of their vaccine supply.

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