Serial Testing of Asymptomatic Health Care Workers Following Vaccination

Last Updated: February 3, 2021

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This Briefing Note was completed by the Research, Analysis, and Evaluation Branch (Ministry of Health)
based on information provided by members of the COVID-19 Evidence Synthesis Network. Please refer to the Methods section for further information.


This note summarizes available recommendations from various jurisdictions for serial testing of
asymptomatic health care workers (HCWs) working in health care settings with direct patient contact following COVID-19 vaccination, including evidence regarding the possible reduction of post-vaccine asymptomatic SARSCoV-2 infection and transmission.

*The full version of the Briefing Note including the Appendix can be accessed in the PDF file at the top of the page*

Key Findings

Analysis for Ontario

Overall, additional data is needed to inform an approach to serial testing of symptomatic and asymptomatic HCWs following COVID-19 vaccination.

Supporting Evidence

This section below summarizes findings from research and grey literature associated with testing symptomatic and asymptomatic individuals who work in health care settings and have direct patient contact (e.g., physicians, nurses, personal support workers, orderlies, etc.) following SARS-CoV-2 vaccination. For ease, these workers will be referred to as health care workers (HCWs) throughout this Evidence Synthesis Briefing Note; details of the specific professions involved in each study are presented where available.

Scientific Evidence

  • No identified academic or grey literature addresses recommendations on serial testing of asymptomatic HCWs following COVID-19 vaccination.
    • Transmission upon vaccination: Three top global evidence synthesis teams (i.e., COVID-NMA, the Copenhagen Trial Unit (CTU), and McMaster Health Forum) are currently developing living evidence syntheses that address questions about COVID-19 vaccine safety and effectiveness; however, no team has yet identified studies that report the reduction of onward COVID-19 transmission upon vaccination. They are committed to reporting the data if/when they become available.
  • The US Centers for Disease Control and Prevention (CDC) provides recommendations, including viral testing, to minimize the impact of post-vaccination systemic signs and symptoms on health care staffing. These include:
    • Developing a strategy to provide timely assessment of HCWs with systemic signs and symptoms post-vaccination, including providing or identifying options for SARS-CoV-2 viral testing.
  • Suggested approaches to evaluating and managing new-onset systemic post-vaccination signs and symptoms in HCWs are provided in the Appendix accessible in the PDF file at the top of the page.

Canadian Scan

  • The BC Centre for Disease Control (BC CDC) suggests that HCWs, including those working in assisted living facilities, who experience symptoms other than local injection site reactions are advised to refer to the BC COVID-19 Self-Assessment Tool. This will inform HCWs if they must get tested. If HCWs require a COVID-19 test, the BC CDC advises the worker is not to return to work until they receive a negative test result.


The COVID-19 Evidence Synthesis Network is comprised of groups specializing in evidence synthesis and knowledge translation. The group has committed to provide their expertise to provide high-quality, relevant, and timely synthesized research evidence about COVID-19 to inform decision makers as the pandemic continues. The following member of the Network provided an evidence synthesis product that was used to develop this Evidence Synthesis Briefing Note:

  • COVID-End in Canada