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Editor’s Take: On vaccine efficacy

Editor’s Take: On vaccine efficacy

One of the key metrics that crop protection products are evaluated on is one known as ‘efficacy.’

You’re quite right if you think that’s a $5 word for ‘effectiveness.’ Whether or not a crop protection product does what it says it will do is a critical part of its evaluation by federal regulators.

If it doesn’t, say, control the weeds it says it controls, it’s not going to get the Pest Management Regulator Agency (a division of Health Canada) approval that is required for a company to market it in this country.

Farmers — and their advocacy groups — spend a lot of time and energy defending science-based decision-making around these sort of tools. Without it, many claim, we’ll simply be facing regulatory gridlock as one group or another cherry-picks data to back up the result it is hoping for.

In the agriculture sector we’ve seen this play out as borders have closed due to ginned-up phytosanitary concerns like blackleg in canola shipments.

But the thing about science is you can’t cherry-pick your data. If the data supports a conclusion, after review, you have to accept that conclusion, unless it’s later proven otherwise.

That’s the sometimes clunky and unwieldy scientific method that’s taken humankind to the pinnacle of its achievements, such as space flight.

Here in Manitoba we’ve got a case of cherry-picking playing out before our very eyes, with some very compelling data.

I speak of COVID vaccinations and their ability to protect from the virus that’s kept us all hostage for the past year and a half.

As I write, Manitoba seems to be at the beginning of its fourth (and one hopes final) wave and for the first time in a while, COVID cases hit the triple digits on August 25, with a total of 105 cases.

That’s disheartening and, even more alarming, about a third of those cases were among the immunized. At first blush it might be enough to make one wonder what the point of all the masking, lockdowns, social distancing and vaccinations was.

But when you dig into those numbers just a bit deeper, a much more positive picture began to appear. The province said that 70 of the cases were among unvaccinated and 35 were among the vaccinated.

Manitoba has an impressive vaccination rate, with more than 83 per cent of the eligible population having got at least one shot, and 75 per cent having received two.

The province didn’t say exactly what its definition of unvaccinated and vaccinated was. For example, is the eight per cent of the eligible population with one shot considered vaccinated or unvaccinated?

Better data — and the province certainly has it — would help us all make better decisions. Why it isn’t being released, as it is in other provinces, is perplexing.

But let’s dive into it using the most conservative interpretation possible – that 25 per cent of the eligible population is unvaccinated and 75 per cent is vaccinated.

Manitoba has a population over 12 years of age of roughly 1.2 million, so that would be 300,000 unvaccinated Manitobans and 900,000 vaccinated Manitobans.

Some rough, back-of-the-envelope scratching suggests that would translate into a case rate of 23 per 100,000 people, based on those 105 cases with 70 among the unvaccinated. And among the vaccinated it would be closer to 3.8 per 100,000 of population using the same numbers.

That means an unvaccinated person is about six times more likely to fall ill from COVID. And these figures don’t even take into account the other great efficacy effect. The vaccines are proving to be excellent at preventing these ‘breakthrough’ infections in the vaccinated from becoming serious illnesses.

In the U.S., where the Delta variant has been well-established for far longer, they’re finding that virtually all of the hospitalizations are amongst the unvaccinated, giving rise to the phrase ‘pandemic of the unvaccinated.’

Here in Manitoba, resistance to vaccination seems to be a largely rural issue. The five health regions with the lowest vaccination rates form a band across southern Manitoba: Stanley (22 per cent), Winkler (38.5 per cent), Hanover (45.7 per cent), Altona (49.6 per cent) and North Norfolk (50.1 per cent).

This makes these areas reservoirs for the disease and the numbers bear this out. All of these districts are part of the larger Southern Health Region, and it’s been the single largest contributor to cases of late.

Of the 105 cases, 41 were from the Southern Health Region, and all were unvaccinated, according to provincial officials.

So if rural Manitoba really endorses science-based outcomes, as it so often has claimed, it’s pretty clear they should be rolling up their sleeves en masse — if they haven’t already.

The data clearly supports this course of action.

About the author


Gord Gilmour

Gord Gilmour is Editor of the Manitoba Co-operator.



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