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

Burrows AG, Linton S, Thiele J, Sheth PM, Evans GA, Archer S, Doliszny KM, Finlayson M, Flynn L, Huang Y, Kasmani A, Hugh Guan T, Maier A, Hansen-Taugher A, Moore K, Sanfilippo A, Snelgrove-Clarke E, Tripp DA, Walker DMC, Vanner S, Ellis AK. Asymptomatic surveillance testing for COVID-19 in health care professional students: lessons learned from a low prevalence setting. Allergy Asthma Clin Immunol. 2023 Mar 29;19(1):25. 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 Allergy, Asthma & Clinical Immunology suggests that despite a high risk of exposure because of their face-to-face teaching requirements, very few students in healthcare programs caught SARS-CoV-2 during the first three waves of the COVID-19 pandemic. This was even true when counting those with no symptoms. The study was carried out in Kingston, Ontario and led by Dr. Anne Ellis (Queen’s University).

For the purpose of assessing asymptomatic transmission of the virus, students in healthcare programs were selected if they:

  • Did not have COVID-19 symptoms,
  • Had not recently traveled to restricted areas,
  • Had not been in contact with a suspected or confirmed COVID-19 case.

The Kingston, Frontenac, Lennox & Addington (KFL&A) public health region was considered a low COVID-19 prevalence area at the time, with only 1,494 confirmed cases reported from May 2020 to June 2021. Of those, 46.7% of cases occurred in people aged 18-29 years old, an age group that overlapped with this studied population. However, despite a higher risk of exposure than students in other programs, none of the healthcare students participating in the study screened positive for SARS-CoV-2 by RT-PCR.

Take-home messages:

  • Students in healthcare programs are considered a high-risk group for SARS-CoV-2 transmission, whether they show symptoms or not because of face-to-face teaching requirements and presence in clinical settings.
  • COVID-19 had a major impact on healthcare teaching. Appropriate testing, masking, and contact tracing remain essential to protect the most vulnerable and at-risk population groups, with lost training opportunities weighed against community safety.
  • The same challenge still applies today, given the high transmissibility of Omicron.

The Alpha and Delta variants were dominant when this study was conducted. A total of 457 asymptomatic healthcare students from Queen’s University’s Faculty of Health Sciences participated in the study. Participants completed one to five visits, totaling 1,237 PCR tests performed. This study is the first to report data on asymptomatic SARS-CoV-2 infection in the Canadian healthcare student population.