Details view: 2021/11/16 Gabrielle Brankston

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2021/11/16 Gabrielle Brankston

Quantifying Social Contact Patterns in Response to COVID-19 Public Health Measures in Canada.

Abstract: A variety of public health measures have been implemented during the COVID-19 pandemic in Canada to reduce contact between individuals. The objective of this study was to provide empirical contact pattern data to evaluate the effectiveness of public health measures, the degree to which social contacts rebounded to normal levels, as well as direct public health efforts toward age- and location-specific settings.

Methods: Four cross-sectional online surveys were administered to members of a paid panel representative of Canadian adults by age, gender, official language, and region of residence during May (Survey 1), July (Survey 2), September (Survey 3), and December (Survey 4) 2020. A total of 4981 (Survey 1), 2493 (Survey 2), 2495 (Survey 3), and 2491 (Survey 4) respondents provided information about the age and setting for each direct contact made in a 24-hour period. Contact matrices were constructed and contacts for those under the age of 18 years imputed. The next generation matrix approach was used to estimate the reproduction number for each wave of the survey. Respondents with children under 18 estimated the number of contacts their children made in school and extracurricular settings.

Results: The estimated R values were 0.49 (95% CI: 0.29-0.69) for Survey 1, 0.48 (95% CI: 0.29-0.68) for Survey 2, 1.06 (95% CI: 0.63-1.52) for Survey 3, and 0.81 (0.47-1.17) for Survey 4. The highest proportion of reported contacts occurred within the home (51.3% in Survey 1), in ‘other’ locations (49.2% in Survey 2) and at work (66.3% and 65.4% in Surveys 3 and 4, respectively). Respondents with children reported an average of 22.7 (95% CI: 21.1-24.3) (Wave 3) and 19.0 (95% CI 17.7-20.4) (Wave 4) contacts at school per day per child in attendance.

Conclusion: The skewed distribution of reported contacts toward workplace settings in Surveys 3 and 4 combined with the large numbers of reported school-related contacts provides evidence that these settings represent important opportunities for transmission emphasizing the need to support and ensure evidence-based infection prevention and control procedures in both workplaces and schools.

Gabrielle is a PhD candidate focusing on the epidemiology and mathematical modelling of infectious disease. She completed her MHSc in Epidemiology at the University of Toronto in 2006 and her MSc in Medical Science at the University of Alberta in 2002. Her professional background includes both hospital infection control and local public health epidemiology. Given her strong interest in outbreaks, when the COVID-19 pandemic arrived in Canada Gabrielle emerged from graduate student retirement to study all things pandemic. Fortunately, she was already working as a research coordinator with her current thesis advisor Dr. Amy Greer, resulting in a seamless transition back to grad studies.