When basic logic and truth get mangled by assumptions

Dr. Julie Ponesse speaks with viral immunologist Dr. Byram Bridle about the recent CMAJ article and how its implications and assumptions lead to contradictions, erroneous outcomes and stigmatization.


I spoke with Dr. Byram Bridle, Associate Professor of Viral Immunology in the Department of Pathobiology at the University of Guelph, about the recent CMAJ article that was published on April 25, 2022, titled, Impact of population mixing between vaccinated and unvaccinated subpopulations on infectious disease dynamics: implications for SARS-CoV-2 transmission.” The paper concludes that the unvaccinated are disproportionately contributing to more COVID-19 infections among the vaccinated.

The authors of this study use an epidemiological mathematical model, which is essentially a computer program, to make their predictions of real-life scenarios. These conclusions rely heavily on the quality of information that is being inputted into the model. If these models are used correctly, they can be an important tool for informing public health decisions, but when used incorrectly, Dr. Bridle emphasizes, they can be very dangerous and result in predictions that are vastly overestimated.

We discuss the use of parameters, which are the key variables the authors relied on as part of the data they inputted into the computer program. These parameters should normally be determined and cited from current and weighted scientific literature.

For the CMAJ study, Dr. Bridle argues that the parameters used were incorrect and based on assumptions. He points out a number of assumptions that were made around vaccine efficacy and the duration of immunity post vaccination, as well as around the incidence of natural immunity in the unvaccinated population. When altering the parameter of natural immunity in the model from 20% to 85% of the population, Dr. Bridle shows how a completely different result is reflected.

We examine current data including rates of COVID-19 among the double vaccinated, the boosted and the unvaccinated, and the lack of transparency that has occurred in relation to hospitalization data.

We look at the definition of a vaccine and how, in 2021, the CDC changed the definition of a vaccine from a product that confers immunity to a product that induces an immune response. Traditionally, vaccines have prevented people from getting sick and from transmitting disease to other individuals, but with the new COVID-19 vaccines, this has not been the case, which has been acknowledged by public health officials and politicians. We discuss the traditional purpose of the vaccine and how, if you were vaccinated with a traditional vaccine, it was safe to mix with the unvaccinated because you were protected and had immunity.

We touch on the divisive language in the article that stigmatizes the unvaccinated and discourages the mixing of the vaccinated with the unvaccinated, and how this article promotes segregation and discrimination.

Finally, we talk about the peer-review process that the authors of a journal article must go through prior to having an article published, the element of human error and that just because a paper gets published, does not mean it is the ultimate truth.

Read Dr. Bridles rebuttal to the CMAJ paper: Fiction Disguised as Science to Promote Hatred.

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Dr. Julie Ponesse

Dr. Julie Ponesse


Dr. Julie Ponesse is the Ethics Scholar for The Democracy Fund and author of the new book: My Choice: The Ethical Case Against Covid19 Vaccine Mandates. Dr. Ponesse's focus is on educating Canadians about civil liberties.

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