Does not having a COVID jab increase your risk of a traffic crash?

Introduction

This week’s article was doing the rounds on Twitter in the middle of December. It was called “COVID Vaccine Hesitancy and Risk of a Traffic Crash” and it was by Redelmeier et al (Ref 1). It captured the attention of a few news sites. One headline was “COVID Vaccine Refusers Have 72 Percent Higher Risk of a Serious Traffic Crash, Study Shows” (Ref 2).

The rationale for the study was given in the background to the paper “COVID vaccine hesitancy is a reflection of psychology that might also contribute to traffic safety. We tested whether COVID vaccination was associated with the risks of a traffic crash.”

Vaccine hesitancy is defined by the World Health Organisation as “a delay in acceptance or refusal of vaccination against an important contagious disease despite supply (distribution), access (availability), and awareness (albeit with possible misinformation).” The hypothesis being tested was “individual adults who tend to resist public health recommendations might also neglect basic road safety guidelines.” That’s a subjective judgement, but studies are allowed to test presuppositions.