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. 2021 Apr 13;9(2):E349. doi: 10.9778/cmajo.20200239

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This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY-NC-ND 4.0) licence, which permits use, distribution and reproduction in any medium, provided that the original publication is properly cited, the use is noncommercial (i.e., research or educational use), and no modifications or adaptations are made. See: https://creativecommons.org/licenses/by-nc-nd/4.0/

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Figure 1: — Flow diagram showing creation of study cohorts. Note: OHIP = Ontario Health Insurance Plan, Tdap = tetanus–diphtheria–acellular pertussis.