No, the Canadian study does not show that “antivax” is more dangerous on the road

A Canadian study claims to be Among those injured in road accidents in Ontario, Over-representation of people not vaccinated against Covid. Many publications widely distributed in social networks conclude that this “anti-vax” have”much more dangerous” on the road than those who are vaccinated. But the study does not allow for this conclusion: it emphasizes correlation, not causation, between people injured in accidents and their vaccination status. No correlation allows and does not allow for generalization beyond this Canadian sample. Also, people who have not been vaccinated against Covid are generally not “antivax”, which defines those who are fundamentally anti-vaccination. Finally, the study did not distinguish between drivers, passengers or pedestrians. among the wounded. Several experts interviewed by AFP highlighted the many biases and limitations of this study.

According to one study, Antivax would be more dangerous on the road“, says the website Détours on 19 December 2022. Détours, a website specializing in ‘mobility’ launched by Canal Plus and car manufacturer Seat, continues: “People who do not want to be vaccinated against Covid-19 will be more likely to be involved in serious traffic accidents. More, even“.

Detours, according to the Canadian study cited, these people “a very rough consideration of risks“.”Meditating as you approach the next wave and the next turn?“, concludes the article.

This study was carried out by many media, in particular by has many, many more serious traffic accidents than others.”and in the subheading: “and it’s not so surprising”.

On December 15, the site’s front page article, illustrated with a photo of a car stunt, goes further, more or less accusing the unvaccinated of being a public menace: “In short, to think yourself invincible to a virus that will only harm others, and against which any defense is nothing more than a nasty government ploy to control the population, is also to think yourself invincible to sycophants or other virus users. road – who pays the price there too”by many Internet users it is “proof” about the danger”anti-vax”.

Screenshot of the Korii website on January 5, 2023

The study on which this French media is based was published in the American Journal of Medicine on December 2, 2022 (Journal of the American Medical Association, not to be confused with the popular JAMA) and in English it is called “Vaccination hesitancy and the risk of traffic accidents”.

It was widely discussed in press articles in North America, as published here or here , a few days later by Corii and Détours in France, as well as by the site Caradisiac.Are drivers not vaccinated against covid-19?

These posts have generated a lot of comments and reposts on social media, especially here on Facebook. The information led to very harsh comments from anti-Covid vaccine skeptics who mocked the research.”to anything and everything“.”So do vaccines protect against accidents? great!“One of them laughs.

The French publications, especially those of Détours and Korii, go further than the authors of the study by extrapolating several data and assuming that any unvaccinated person will necessarily oppose, creating a practice between unvaccinated people and “antifakes”. with ideological conviction.

What does Canadian research say behind these publications?

Hesitancy over Covid vaccine linked to increased risks down the road”highlight the authors, comparing the risks of unvaccinated people on the road with those who suffer from sleep apnea, page 2. The authors believe that the risk factor is related to “lack of vaccination” remains lower than that associated with alcohol.

The researcher behind this study, Dr. Donald A. Redelmeier of the University of Toronto, is used to researching unusual subjects. “Traffic deaths on US presidential election days“or”Longevity of Oscar-winning actors and actresses”according to this August 2010 New York Times article.

According to the New York Times, this tropism for car accidents comes from his position as an intern at Sunnybrook Hospital in Toronto, where he treats many traffic victims.

His latest research involved analyzing the accident history of the Ontario population over a period of one month. The researchers examined data from all adults who were injured in a traffic accident and consulted in the emergency room.

The study includes 11 million people, a “cohort” that at first glance is huge but actually includes the entire adult population of Ontario. As of July 31, 2021, 16% have not been vaccinated against Covid-19.

Out of these 11 million people, 6,682 sought emergency help after a road accident. Asked by AFP about the study, Romy Sauvaire, a sociologist specializing in science and faith, notes that “this large difference between these two numbers can cause sampling problems“.

Of all these consultations, 1,682 were for unvaccinated individuals. i.e., 25% of the total population, considering the proportion of the total cohort (16%), according to the authors, this group presents a 72% higher risk of being a victim of a traffic accident than vaccinated people.

Screenshot of Donald Redelmeier’s research

For Donald A. Redelmeier, this difference between “vaccinated” and “unvaccinated” can be explained by “.distrust of government and a strong belief in the value of freedom“, but also with “poor perception of everyday risks, belief in natural protection and reluctance to follow rules“.

Prejudice and confusion

Laurent-Henri Vignaud, a professor of modern history at the University of Burgundy and an expert on vaccine resistance, told AFP that indeed “Avoidance of vaccinations can be attributed to “natural” risk reduction“, related to “a feeling of overpowering“.

Assuming (which remains to be proven) that those responsible for accidents among non-drivers are indeed responsible, we can estimate that these drivers [s’estimeraient] suitable for driving in all conditions”Mr. Vignaud continues, believing that we can’t really draw much from this study.

In addition, the researcher notes: the study is not about “antivax,” but about “nonvaccination,” “Those who don’t get vaccinated because they don’t see benefits, not because they’re against vaccination or because they think it’s dangerous.” their sociology is often different.

“Study Focuses on Non-Vacs – More Among Lower Class”, Especially for a social class that is more at risk on the road “the car is in bad condition”, notes.

“There are so many prejudices [dans cette étude] it can produce amazing results! (in statistics, this is called “confounding bias”: for example, a study shows that coffee drinkers get lung cancer more often, the conclusion: coffee causes cancer? No, heavy smokers are also coffee drinkers, and they Raise the Stats…)” , the researcher explains.

Another limitation of the study is that we do not know whether unvaccinated people are responsible for more serious accidents than others: pThe 3-year-old Mr. Redelmeier of the study states that he defines himself as “.serious traffic accidents” accidents that result in hospitalization of the driver as well as a pedestrian or passenger.

“Our study does not analyze responsibility in the event of an accident,” The researcher confirmed the contact via email to AFP “Sometimes a car accident is completely caused by a third party, but it is very difficult to prove.”

However, reading the research, one can observe that one-third of the victims were pedestrians.

Screenshot of the study, prepared on January 5, 2023

In addition to the issue of liability, Mr. Vignaud believes that research suffers greatly “confusion bias”, eg “urban/rural” bias and exposure to road risk.

The authors of the Canadian study also recognize a number of limitations, notably the failure to take into account the distance traveled by accident victims each day.

In addition, the profiles of people who were injured in the study were similar to the profiles of unvaccinated people in Canada,” according to a study titledAnti-covid vaccination wavers among young adults in Canada Published by the Canadian Journal of Public Health in October 2022, it shows that unvaccinated people under the age of 40 mostly have low incomes and low levels of education.

“Observational Correlation Research”

“The authors hypothesize that adults who are unwilling to follow public health recommendations are also more likely to ignore road safety rules.” American surgeon and oncologist Dr. who gave an interview to AFP. David Gorski summarizes: “It is clear from the outset that this is an observational correlational study, and correlation does not mean causation.”

Dr. Gorski notes that this a “retrospective study”, based on public information, “and although the authors ran several analyzes to control for confounders, you can never be sure that there wasn’t one left that skewed the results.”

David Gorski confirms this about the bias of human responsibility in accidents “The research doesn’t seem to have even considered this question (…) so it’s a mix of responsible and non-responsible people, which is probably the best that can be done without individual data on the subject.”

In the study itself, the authors mention that “correlation does not imply causation,” “because our data do not examine potential causes of vaccine avoidance or risky behavior.”

Despite this caution, their savings still strongly emphasizes the responsibility of the unvaccinated accidents: ““The results show that unvaccinated adults should be cautious of others indoors and outdoors in traffic.”

They even go so far as to give advice:the observed risks can also justify changes in insurance policies in the future.”

“This study creates nonsense”

Romy Sauvaire, A sociologist of science and beliefs at the University of Clermont-Ferrand notes that research “square[e] on statistical analysis […] -unvaccinated people have a really high risk of getting into an accident-,he could have been more careful when he said the last sentence ‘unvaccinated people should be careful’.

In effect, “Generalizing the results of the Canadian study to other regions is very complicated: socio-demographic profiles for people who refuse vaccination differ from one country to another, for example, it is difficult to compare Canada with France. French. Women are slightly more reluctant to be vaccinated than men, while there the opposite it seems.”

Apart from the nature of the research, the sociologist doubts Redelemeyer’s chosen starting postulate: “vsThis study is nonsense because it tries to test the already false hypothesis of a link between vaccination status and the risk of traffic accidents.

Any study has many limitations, but the most important one is not to let the data say what it doesn’t say.“, he concludes, fearing the outcome of such a highly viral investigation on social media”strong discrimination” as for the unvaccinated.

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