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A new study from Canada set out to test whether Covid “vaccine hesitancy” was associated with the risks of a traffic crash.  It claims there is a link between “vaccine hesitancy” and “risky driving.”  But the point of the study is revealed in their conclusion so read on …

Any rational person would read the title – ‘Covid Vaccine Hesitancy and Risk of a Traffic Crash’ – and assume it was satire.  But the editors of The American Journal of Medicine didn’t think it was a joke – they published it.  And the Stanford Department of Biomedical Data Science and the Princeton University Centre for Behavioural Science & Public Policy didn’t think it was a joke either – they provided “helpful suggestions on specific points.”

It’s worth noting it took three researchers to conduct this study. Plus, another seven to give “helpful suggestions.” Because of their great service to science and humanity, we feel the authors deserve to be named.  The lead author is Donald A. Redelmeier, a doctor in Toronto, Canada.  He was assisted by:

• Jonathan Wang, at the Department of Medicine University of Toronto, and
• Deva Thiruchelvam, who is affiliated with Evaluative Clinical Sciences, Sunnybrook Research Institute and Institute for Clinical Evaluative Sciences (ICES).

The number of researchers involved is not the only surprise the study holds.  Incredibly, it has been peer-reviewed, which calls into question who the peers were and the value of their “review.”

Funding for the researchers to carry out what must be the most senseless study ever conducted was provided by a Canada Research Chair in Medical Decision Sciences, the Canadian Institutes of Health Research, the Graduate Diploma in Health Research at the University of Toronto, and the National Sciences & Engineering Research Council of Canada.

The main problem is its moral compass, tweeted pathologist Dr. Clare Craig, but the entire thing is based on a data error.  Dr. Craig posted a summary of the study in a Twitter thread which we’ve copied below.

[The study states that] because of “a distrust of government or belief in freedom that contributes to both vaccination preferences and increased traffic risks.”

It goes on …

“A different explanation might be misconceptions of everyday risks, faith in natural protection, antipathy toward regulation, chronic poverty, exposure to misinformation, insufficient resources, or other personal beliefs.”

These claims are based on accidents which resulted in hospitalisation.  Each person injured is referred to in the paper as a “crash” – even when the injured person was a pedestrian!

“Results show substantial incidence of serious traffic crashes that is increased for those who are not vaccinated relative to those who are vaccinated.”

There is a fundamental error in how they reached that conclusion. They used two sets of data:

1. the numbers of people presenting to hospital after a traffic accident
2. The number of people in the government vaccination database

Nowhere do they talk about people who are not in the system.  Someone not in the government [vaccine] data could still be in an accident. They would still go to hospital if injured. Only then would they be added to the government data.  All those people who are not in the system and remained healthy are not counted.

Accidents in [vaccine] are measured as a proportion of those [vaccine]. Accidents in the [no vaccine] are measured as a proportion of those [no vaccine] and in the system.

This table shows the problem clearly.  No matter which way you chop the data the risk is apparently increased by about the same amount.  The vertical line at point 1 should be picked up and lifted across to where all the dots are.

You still see an increased risk for people with dementia who were not vaccinated (and highly likely to have been pedestrians).  You also see a lower risk for the old, those with diseases of the old and those who had covid.

Using their same methodology, you could estimate that the unvaccinated had a higher rate of anything:

• giving to charity
• recycling
• buying the most Christmas presents

… whatever you want when the levels are actually the same – because the denominator is artificially small.

The point is probably best made by the number of people they claim to have in the database: 11,270,763.  Not 11,300,000.  It was exactly 11,270,763.  It is not possible to measure the size of a city that accurately.

Their conclusion is worth sharing too:

“These data suggest that Covid vaccine hesitancy is associated with significant increased risks of a traffic crash. An awareness of these risks might help to encourage more Covid vaccination.”

Dr. Craig ended by reposting and remarking on a reply to her thread, see below. “Good point!” she wrote.

“An awareness of these risks might help to encourage more Covid vaccination.”  This sentence, this is what the funders paid for. It would be interesting to know how much that sentence cost the funders, how much they were prepared to pay to have it published in The American Journal of Medicine.

Professor Norman Fenton tweeted: “Great thread by @ClareCraigPath exposing flaws in the ludicrous article claiming unvaxxed are more likely to be in a car accident. I’d note one additional confounder: unvaxxed are more likely to travel since they aren’t too scared to leave home.”

And then made a video about it: