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, Gong Y, Huang Y, Kasmani 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. April 11, 2022, Research Square,

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

A CITF-funded study in preprint, currently under peer review, led by Dr. Anne Ellis (Queen’s University), suggests that despite a high risk of exposure because of their age and the fact that they were studying in healthcare settings, a very low number of healthcare students in Kingston, Ontario tested positive for SARS-CoV-2 during the first three waves of the COVID-19 pandemic, even when counting those with no symptoms.

For the purpose of assessing asymptomatic transmission of the virus, healthcare students were selected based on not having COVID-19 symptoms, not having recently traveled to restricted areas, or not having 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, which overlapped with this studied population. However, despite a higher risk of exposure than students in other areas, none of the healthcare students participating in the study screened positive for COVID-19 by RT-PCR.

Take-home messages:

  • Healthcare students are considered a high-risk group for SARS-CoV-2 transmission, whether they show symptoms or not. Because of face-to-face teaching requirements, often in outpatient and inpatient clinical settings, they pose a risk of contracting the virus and of infecting patients, faculty members and peers.
  • Nasopharyngeal RT-PCR screening tests are the gold standard to detect SARS-CoV-2 infections. Yet, they are very resource-intensive as they must be administered by healthcare professionals and were difficult to obtain during the early stages of the pandemic.
  • 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.