SARS-CoV-2 infection among healthcare workers: the role of occupational and household exposures during the first three pandemic waves in Quebec, Canada

Sara Carazo; Geoffroy Denis; Lauriane Padet; Pierre Deshaies; Jasmin Villeneuve; Bianka Paquet-Bolduc; Denis Laliberté; Denis Talbot; Gaston De Serres

doi:10.1017/ash.2023.442

SARS-CoV-2 infection among healthcare workers: the role of occupational and household exposures during the first three pandemic waves in Quebec, Canada

Antimicrob Steward Healthc Epidemiol. 2023 Oct 20;3(1):e180. doi: 10.1017/ash.2023.442. eCollection 2023.

Authors

Sara Carazo^{1

2}, Geoffroy Denis^{3

4

5}, Lauriane Padet¹, Pierre Deshaies⁶, Jasmin Villeneuve¹, Bianka Paquet-Bolduc⁷, Denis Laliberté⁸, Denis Talbot^{2

9}, Gaston De Serres^{1

2

9}

Affiliations

¹ Biological and Occupational Risks Unit, Institut national de santé publique du Québec, Quebec City, QC, Canada.
² Social and Preventive Medicine Department, Faculty of Medicine, Laval University, Quebec City, QC, Canada.
³ School of Population and Global Health, Faculty of Medicine, McGill University, Montreal, QC, Canada.
⁴ Public Health Department, CIUSSS Centre Sud de Montréal, Montreal, QC, Canada.
⁵ General Directorate of Public Health, Quebec Ministry of Health and Social Services, Quebec City, QC, Canada.
⁶ Public Health Department, CISSS de Chaudière-Appalaches, Levis, QC, Canada.
⁷ Infection Prevention and Control Unit, Institut Universitaire en cardiologie et pneumologie de Québec, Quebec City, QC, Canada.
⁸ Public Health Department, CIUSSS de la Capitale-Nationale, Quebec City, QC, Canada.
⁹ CHU de Québec-Laval University Research Center, Quebec City, QC, Canada.

Abstract

Objective: We described the evolution of SARS-CoV-2 source of infection in a cohort of healthcare workers (HCWs) of Quebec, Canada, during the first three pandemic waves. We also estimated their household secondary attack rate (SAR) and its risk factors.

Design: Cross-sectional surveys.

Participants: HCWs with a SARS-CoV-2 infection confirmed by polymerasa chain reaction and diagnosed between March 2020 and May 2021.

Methods: We collected demographic, clinical, vaccination, and employment information, self-reported perceived source of infection, and transmission to household members during the first three pandemic waves. SAR was calculated for households with ≥2 members where the HCW was the index case. A Poisson regression model estimated the association between risk factors and SAR.

Results: Among the 11,670 HCWs completing the survey, 91%, perceived their workplace as the source of infection during the first wave (March-July 2020), 71% during the second wave (July 2020-March 2021), and 40% during the third wave (March-May 2021). Conversely, HCWs reported an increasing proportion of household-acquired infections with each wave from 4% to 14% and 33%, respectively. The overall household SAR of 7,990 HCWs living with ≥1 person was 30% (95%CI: 29-30). SAR increased with the presence of symptoms, older age, and during Alpha-variant predominant period.

Conclusions: HCWs and their household members were largely affected during the first pandemic waves of COVID-19, but the relative importance of occupational exposure changed overtime. Pandemic preparedness in healthcare settings is essential to protect HCWs from emerging biological hazard exposures.