Mandating COVID-19 vaccines? Response to nonsense objections

Colleen M. Flood, Bryan Thomas, and Kumanan Wilson rebut Juan Gérvas’s contention that there is insufficient justification for mandating health care worker vaccination against COVID-19.


In a recent commentary on this site, Juan Gérvas takes issue with our recent article in CMAJ, in which we argue that government should require health care workers to be vaccinated for COVID-19 as a condition of service. The article’s primary focus is on the legalities of mandatory vaccination for health care workers, as we review labour law and Charter jurisprudence to show that such mandates would likely survive legal challenge. Gérvas has no objections on this score, but argues that a vaccination mandate for health care workers is nonsensical from the standpoint of public health.

Gérvas’s primary objection is that, to date, there is still no definitive data showing that COVID-19 vaccines prevent transmission of SARS-CoV-2. Given this uncertainty, he argues, one cannot argue for mandatory vaccination on grounds of preventing disease spread among patients and health care workers. Gérvas accuses us of claiming that vaccines prevent transmission, when in fact we repeatedly note the scientific uncertainty. Indeed, our article concludes with a plea for robust postmarket surveillance of the vaccines, precisely to address this issue.       

Photo Credit: AlamosaCounty PublicHealth/flickr. Image description: A health care worker in full personal protective equipment.

Our article is clear-eyed about the scientific uncertainty, and our call for mandatory vaccination of health care workers is explicitly grounded in the precautionary principle. (As data emerges showing that mRNA vaccines reduce viral load, the precautionary approach appears to be all the more prudent).  Gérvas objects that, “[w]e cannot apply the precautionary principle to justify mandatory vaccination of health care workers because the risk of spread could increase if, after vaccination, people mistakenly act as if they are no longer capable of harboring contagion.”  No evidence is offered to substantiate the concern that health care workers will behave recklessly in this way; nor is any explanation offered as to why this concern should eclipse all others in applying the precautionary principle to the issue of health care worker vaccination.    

Earlier in the pandemic, some speculated, along similar lines, that a universal mask mandate would cause the public to neglect other measures (such as physical distancing).  Sociologists such as Zeynep Tufecki were quick to denounce this line of argument – pointing out that the theory of “risk compensation” has been largely rebutted.  At any rate, if vaccinating health care workers leads to their behaving recklessly, that is a problem we must address regardless of whether vaccination is voluntary or mandated as a condition of service.

Gérvas concludes by emphasizing that, given the scientific uncertainty as to whether COVID-19 vaccines prevent transmission, calls for mandatory vaccination of health care workers jeopardize public trust. This is nonsense: no deception or prevarication is required in making the case for mandatory vaccination, grounded in the precautionary principle.  If anything, Gérvas’s pessimistic and unfounded assumption that health care workers will behave recklessly post-vaccination seems more corrosive to public trust.


Colleen M. Flood is University Research Chair in Health Law and Policy at the University of Ottawa. @ColleenFlood2

Bryan Thomas is a Senior Research Associate and Adjunct Professor in the Faculty of Law at the University of Ottawa. @bryanpaulthomas

Kumanan Wilson is a Professor in the Department of Medicine at the University of Ottawa.