Incidence of outbreak-associated COVID-19 cases by industry in Ontario, Canada, 1 April 2020-31 March 2021

Sarah A. Buchan, Peter M. Smith, Christine Warren, Michelle Murti, Cameron Mustard, Jin Hee Kim, Sandya Menon, Kevin A. Brown, Trevor van Ingen, Brendan T. Smith

Research output: Contribution to journalArticleResearchpeer-review

22 Citations (Scopus)


OBJECTIVES: The objective of our study was to estimate the rate of workplace outbreak-associated cases of COVID-19 by industry in labour market participants aged 15-69 years who reported working the majority of hours outside the home in Ontario, Canada. METHODS: We conducted a population-based cross-sectional study of COVID-19 workplace outbreaks and associated cases reported in Ontario between 1 April 2020 and 31 March 2021. All outbreaks were manually classified into two-digit North American Industry Classification System codes. We obtained monthly denominator estimates from the Statistics Canada Labour Force Survey to estimate the incidence of outbreak-associated cases per 100 000 000 hours among individuals who reported the majority of hours were worked outside the home. We performed this analysis across industries and in three distinct time periods. RESULTS: Overall, 12% of cases were attributed to workplace outbreaks among working-age adults across our study period. While incidence varied across the time periods, the five industries with the highest incidence rates across our study period were agriculture, healthcare and social assistance, food manufacturing, educational services, and transportation and warehousing. CONCLUSIONS: Certain industries have consistently increased the incidence of COVID-19 over the course of the pandemic. These results may assist in ongoing efforts to reduce transmission of COVID-19 by prioritising resources, as well as industry-specific guidance, vaccination and public health messaging.

Original languageEnglish
Pages (from-to)403-411
Number of pages9
JournalOccupational and Environmental Medicine
Issue number6
Publication statusPublished - 1 Jun 2022
Externally publishedYes


  • COVID-19
  • disease outbreaks
  • epidemiology
  • occupational health
  • public health surveillance

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