New model helps determine who should get a COVID-19 vaccine first

Tuesday, October 6, 2020

Researchers have developed a new model to help authorities determine which sector of the population should get COVID-19 vaccination first.

If a vaccine becomes available in January 2021 or shortly after, it should be given to people 60 years old and older first, since they have the highest death rate from COVID-19. According to the model, if the vaccine becomes available in the summer of 2021, the priority group changes.

The model can be populated with information from any province or country to decide the vaccination strategy that would prevent the most COVID-19 deaths in that population. 

“When a vaccine becomes available many people will want to be vaccinated at first, and there might be supply issues, so policymakers will have to prioritize which ages should get it first,” Chris Bauch, co-author of the study and a professor in Waterloo’s Department of Applied Mathematics, says. “Under those conditions, the best vaccination strategy for a specific region depends on when the vaccine becomes available, the number of people in a population who have contracted COVID-19 and are now immune, and the social reaction to the virus, such as the wearing of a mask and social distancing.”

The social-epidemiological model suggests four COVID-19 vaccine strategies to prevent the most deaths from the virus: vaccinating people 60 years of age and older first, those 20 years of age and younger first, everybody irrespective of their age, and the fourth tactic is to initially target the sector of the population responsible for the most contacts. The last three strategies interrupt transmission, while the first targets a vulnerable group. 

The researchers also used the model to look at the particular case where people do not change their mask-wearing or social distancing behaviour over time. In that case, they found that the latter three strategies designed to interrupt transmission work better both in January and in July.

“This research exemplifies how important it is to factor human behaviour into mathematical models of the pandemic,” Madhur Anand, Professor in the School of Environmental Sciences, University of Guelph and Adjunct Professor in Waterloo’s Department of Applied Mathematics, says. “We all have a hand, or I should say, a mask, in this.”

The study, Prioritising COVID-19 vaccination in changing social and epidemiological landscapes, co-authored by Waterloo’s Faculty of Mathematics professor Bauch, Anand and PhD candidate in Waterloo’s Department of Applied Mathematics Peter Jentsch, has been submitted for peer-review and publication.

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