This is a summary, written by members of the CITF Secretariat, of:

Cherry N, Adisesh A, Burstyn I, Durand-Moreau Q, Galarneau JM, Labrèche F, Ruzycki S, Zadunayski T. Cohort profile: Recruitment and retention in a prospective cohort of Canadian health care workers during the Covid-19 pandemic. medRxiv. 2023 Apr 17. doi:

The results and/or conclusions contained in the research do not necessarily reflect the views of all CITF members.

A CITF-funded study, published in preprint and not yet peer-reviewed, reported on the establishment of a longitudinal cohort of health care workers (HCWs) employed in hospitals, residential institutions, and the community. Researchers used the cohort to examine factors in the workplace that might serve to mitigate risk of either SARS-CoV-2 infection or mental distress related to work demands, availability of personal protective equipment, vaccination, and infection during the pandemic. This study was led by Dr. Nicola Cherry (University of Alberta).

Participants were recruited in March 2020 from Alberta, British Columbia, Ontario, and Quebec. The cohort includes physicians (MDs), registered nurses (RNs), licensed practical nurses (LPNs), personal support workers (PSWs), and healthcare aides (HCAs). Blood samples were taken for serology testing before and after vaccination. Measurements of anxiety, depression, and sources of stress were conducted throughout the course of the pandemic.

Key findings:

  • The recruited participants included 29% MDs, 63% RNs, 1.4% LPNs, 4.7% PSWs, and 1.6% HCAs.
  • By the fourth questionnaire in Spring 2022, many participants were retained, with a response rate of 89%.
  • 92% of participants received at least one vaccine dose and 60% gave post-vaccine blood samples. Ease of accessing blood collection sites was a strong determinant of participation.
  • In the early phase of the pandemic, unvaccinated HCWs were at greater risk of infection if they worked hands-on with COVID-19 on a ward designated for care of infected patients, or handled objects used by infected patients.

The authors will assess if medical conditions, medications, and stage of pregnancy added to vaccination, infection, and age in affecting the levels of SARS-CoV-2 IgG antibodies. Serology results and demographic data will be entered into the publicly accessible CITF Databank. The ability to link with provincial administrative health databases will validate self-reports of infection and vaccination, facilitate assessment of longer-term consequences of infection, and allow comparison of HCWs to community controls.