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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Projecting the impact of a two-dose COVID-19 vaccination campaign in Ontario, Canada

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Vilches, Thomas N. [1] ; Zhang, Kevin [2] ; Van Exan, Robert [3] ; Langley, Joanne M. [4, 5] ; Moghadas, Seyed M. [6]
Total Authors: 5
[1] Univ Estadual Campinas, Inst Math Stat & Sci Comp, Campinas, SP - Brazil
[2] Univ Toronto, Fac Med, Toronto, ON M5S 1A8 - Canada
[3] Immunizat Policy & Knowledge Translat, Trent Lakes, ON K0M 1A0 - Canada
[4] Dalhousie Univ, Canadian Ctr Vaccinol, IWK Hlth Ctr, Halifax, NS B3K 6R8 - Canada
[5] Nova Scotia Hlth Author, Halifax, NS B3K 6R8 - Canada
[6] York Univ, Agent Based Modelling Lab, Toronto, ON M3J 1P3 - Canada
Total Affiliations: 6
Document type: Journal article
Source: Vaccine; v. 39, n. 17, p. 2360-2365, APR 22 2021.
Web of Science Citations: 0

Background: A number of highly effective COVID-19 vaccines have been developed and approved for mass vaccination. We evaluated the impact of vaccination on COVID-19 outbreak and disease outcomes in Ontario, Canada. Methods: We used an agent-based transmission model and parameterized it with COVID-19 characteristics, demographics of Ontario, and age-specific clinical outcomes. We implemented a two-dose vaccination program according to tested schedules in clinical trials for Pfizer-BioNTech and Moderna vaccines, prioritizing healthcare workers, individuals with comorbidities, and those aged 65 and older. Daily vaccination rate was parameterized based on vaccine administration data. Using estimates of vaccine efficacy, we projected the impact of vaccination on the overall attack rate, hospitalizations, and deaths. We further investigated the effect of increased daily contacts at different stages during vaccination campaigns on outbreak control. Results: Maintaining non-pharmaceutical interventions (NPIs) with an average of 74% reduction in daily contacts, vaccination with Pfizer-BioNTech and Moderna vaccines was projected to reduce hospitalizations by 27.3% (95% CrI: 22.3% - 32.4%) and 27.0% (95% CrI: 21.9% - 32.6%), respectively, over a oneyear time horizon. The largest benefits of vaccination were observed in preventing deaths with reductions of 31.5% (95% CrI: 22.5% - 39.7%) and 31.9% (95% CrI: 22.0% - 41.4%) for Pfizer-BioNTech and Moderna vaccines, respectively, compared to no vaccination. We found that an increase of only 10% in daily contacts at the end of lockdown, when vaccination coverage with only one dose was 6%, would trigger a surge in the outbreak. Early relaxation of population-wide measures could lead to a substantial increase in the number of infections, potentially reaching levels observed during the peak of the second wave in Ontario. Conclusions: Vaccination can substantially mitigate ongoing COVID-19 outbreaks. Sustaining populationwide NPIs, to allow for a sufficient increase in population-level immunity through vaccination, is essential to prevent future outbreaks. (C) 2021 The Author(s). Published by Elsevier Ltd. (AU)

FAPESP's process: 18/24811-1 - Mathematical modelling for the transmission of schistosomiasis in low-prevalence areas
Grantee:Thomas Nogueira Vilches
Support type: Scholarships in Brazil - Post-Doctorate