To me, this likely indicates that the estimates of the number of vaccinated are likely exaggerated. There are a number of ways that the data can be confounded. For instance, their base dataset likely includes many individuals who do not drive. The subset of people in their dataset that do drive are likely to be younger and fitter (the old and sick don't drive as much) and less likely to be jabbed. There is also very likely over estimation of the proportion that are jabbed. The over estimation of the jabbed is "convenient" for the authorities as it: - gives an impression of compliance for use in propaganda. - shows higher vaccine efficacy (as the cases in the vaccinated are spread over an elevated number of people) - shows higher death and hospitalisation in the unvaccinated (as they are spread over a reduced number of people). If the number of vaccinated was over estimated, the results of this study become unsurprising.