Best Practices for Limiting the Transmission of COVID-19 Variants of Concern

Last Updated: February 24, 2021

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This Briefing Note was completed by the Research, Analysis, and Evaluation Branch (Ministry of Health).


This briefing note provides a summary of best practices for limiting the transmission of COVID-19 variants of concern (VOCs).

*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 and Implications

Implications for Ontario: Despite the recent emergence of VOCs in Ontario, there have been no updated recommendations or changes to IPC and public health measures. VOCs and potential changes to measures should be closely monitored in the coming weeks.

Implementation Implications for Ontario:


According to a Public Health Ontario (PHO) report (Feb 15, 2021) on COVID-19 VOC in Ontario, there are three COVID-19 VOCs that have been identified in Ontario, including: PANGO lineage B.1.1.7: first detected in the United Kingdom (UK) in September, 2020; PANGO lineage B.1.351: first detected in South Africa in October, 2020; and PANGO lineage P.1: first detected in Brazil in January, 2021.

A European Centre for Disease Prevention and Control (ECDC) report (Feb 15, 2021) on the increased circulation of VOCs in the European Union (EU) notes that despite measures being in place in most countries, the circulation of variants has progressed in terms of the number and proportion of all cases. There is substantial uncertainty regarding severity estimates for VOC B.1.351 and P.1. Furthermore, if the variant B.1.351 or other variants are found to partially or fully evade available vaccines, this may prolong or worsen the impact, particularly for those most likely to suffer from severe outcomes.

The ECDC report (Feb 15, 2021) further notes that modelling analysis shows that, unless non-pharmaceutical interventions (NPIs) continue or are strengthened in terms of compliance over the coming months, a significant increase in COVID-19-related cases and deaths is anticipated. Although vaccination may mitigate the effect of more transmissible variants, easing measures prematurely will lead to a rapid increase in incidence rates and mortality. In areas where new VOCs have emerged or are anticipated to be the dominant variant in circulation, stringent implementation of NPIs are necessary to reduce transmission and safeguard the functioning of health care systems. Higher transmissibility implies that the effectiveness of several individual NPIs (e.g., physical distancing or the use of face masks) may be reduced and that more intensive layering of NPIs will be needed to achieve similar results. Countries should continue or enhance application of NPIs at personal, environmental, and society levels. Such measures include:

  • Encouraging physical distancing between individuals and limiting the size of public and private gatherings;
  • Promoting hand hygiene and respiratory etiquette;
  • Providing advice on use of face masks where necessary;
  • Continuing with contact tracing, quarantine of contacts, and isolation of cases;
  • Limiting transmission in workplaces by encouraging teleworking whenever possible;
  • Recommending measures to maintain IPC in all health and social care settings, including long-term care facilities;
  • Avoid non-essential travel; and
  • Strengthening in-school mitigation measures and, as a last resort after other measures in society have already been applied, considering partial or complete school closures on a short-term basis.

Supporting Evidence

This section below summarizes scientific evidence and jurisdictional experiences on the best practices for limiting the transmission of COVID-19 VOCs. In terms of jurisdictional experience, information is presented on Canada (Ontario, Manitoba), Europe (UK), and the United States (US).

Additional details are provided in Table 2 (best practices for limiting the transmission of COVID-19 VOCs) in the Appendix (accessible in the full PDF at the top of the page).

Scientific Evidence

  • Preventing Transmission: No information identified.
  • Aerosol Transmission (HVAC): No information identified.
  • IPC and Public Health Measures:
    • PPE: Face coverings are recommended in all indoor public spaces, schools, workplaces, and crowded outdoor spaces. Wearing a face covering with a filtering face piece (FFP) is of particular importance with respect to limiting the transmission of VOCs. Electrospun air filters are noted to contain composite air filter membranes which may improve protection against more transmissible VOCs.
    • Physical Distancing: Continued physical distancing used in conjunction with other public health measures is recommended with the new VOCs. Furthermore, it is suggested that the physical distancing rule of two meters (i.e., six feet) may need to be expanded given the rise in VOCs.
    • Multiprong IPC and Public Health Measures: The following IPC and public health measures can be used with VOCs where applicable: restrictions on high-risk and high-capacity settings, frequent hand washing, delaying travel, widespread diagnostic testing and screening to identify and isolate infectious individuals, particularly those who are asymptomatic, and quarantining of contacts.

International Scan

  • Preventing Transmission: Continued personal, procedural, engineering, and societal mitigation measures may reduce transmission of SARS-CoV-2 and VOCs (EU, UK). The UK variant (B1.1.7) is significantly more transmissible than previously circulating variants, with an estimated potential to increase the reproductive number by 0.4 or greater with an estimated increased transmissibility of up to 70%. Therefore, in addition to current mitigation measures, stricter measures are needed, including:
    • Reducing non-essential travel and social activities (EU);
    • Implementing population level approaches such as changing the operations of schools/universities, travel restrictions between regions and internationally, and/or introducing a national lockdown (UK);
    • Communicating mitigation measures to the public with a focus on alerting the public and organizations that: 1) previous levels of adherence to preventative measures are unlikely to reduce transmission of the new variant, especially in winter; and 2) environmental and personal measures can still reduce transmission if applied more rigorously, including within the home environment (UK);
    • Immediately identifying people with an epidemiological link to cases with the new variant and following up with reports of suspected cases of COVID-19 reinfection (EU); and
    • Developing standardized mechanisms, in partnership with global stakeholders, to investigate and assess newly emerging variants of SARS CoV-2 (EU).
  • Aerosol Transmission (HVAC): At distances greater than two meters, exposure to the virus is determined by ventilation rates and airflow patterns rather than distance. Therefore, it is important to consider effective ventilation in the workplace, public settings, and in the home. Application of ventilation control currently vary in different settings, and it is essential to ensure that all public and workplace spaces include ventilation as part of their COVID secure risk assessment (UK).
  • IPC and Public Health Measures:
    • PPE: Due to their better filtration efficiency, respirators have been considered for use in the community since the emergence of more transmissible new variants of SARS-CoV-2. Nonetheless, the difficulties to ensure their appropriate fitting and use in community settings as well as potential adverse effects related to lower breathability should be considered (EU).
    • Physical Distancing: Mitigation measures that minimize social mixing between school classes and adult staff should be considered, such as school closures with increased community circulation of VOCs (EU).
    • Multiprong IPC and Public Health Measures: The emergence of VOCs highlights the importance of continuing to comply with local and national public health and social measures simultaneously such as physical distancing, wearing a mask, keeping rooms well ventilated, avoiding crowds, hand hygiene, and coughing into a bent elbow or tissue (Global).

Canadian Scan

  • Preventing Transmission: No information identified.
  • Aerosol Transmission (HVAC): No information identified.
  • IPC and Public Health Measures:
    • PPE: IPC protocols and appropriate and consistent use of PPE remain the most effective measures controlling the spread of COVID-19 and VOCs. If worn correctly and consistently, PPE is proven to be effective (Manitoba)
    • Contact Tracing: The following contact tracing measures are recommended in public transportation settings:
      • Public postings of transportation during periods of communicability should note if a VOC is identified.
      • Flight manifests should be requested for contact tracing of those seated within three rows of an identified COVID-19 case in Economy, or two rows in the Business section. It may be expanded to all passengers if movement is noted or if other factors that increase risk of exposure are present. All contacts identified should be advised to quarantine and be tested.
      • Lower thresholds for public notification of exposures on other conveyances (e.g., buses, taxis) should be considered if contacts cannot be identified (Manitoba).

Ontario Scan

  • Preventing Transmission: Mitigation measures should be reinforced in high-risk settings such as long-term care homes, retirement homes, correction facilities, shelters, group homes and other congregate living settings, childcare centers, and schools that remain open. Overall, facilities and settings should review, audit, and reinforce consistent implementation of IPC measures (i.e., screening staff and visitors, universal masking, PPE, hand hygiene, physical distancing and environmental cleaning) to reduce the transmission of COVID-19 and any variant (Toronto).
  • Aerosol Transmission (HVAC): No information identified.
  • IPC and Public Health Measures:
    • PPE: There is no recommended change in PPE practices related to the emergence of the B.1.1.7 VOC or other VOCs in Ontario.
    • Physical Distancing: Health care settings must ensure that all essential measures controlling the spread of non-variant SARS-CoV-2 (NVSC2) are in place or the risk of nosocomial transmission and outbreaks with VOCs may be substantial. Health care providers should have sufficient break space where they can safely eat and drink to avoid crowding and ensure appropriate physical distancing and masking in these areas.
    • Disinfection and Hygiene: Environmental cleaning in health care settings is important to reduce the risk of SARS-CoV-2 transmission although indirect contact transmission through contaminated surfaces and equipment is not considered the primary mode of SARS-CoV-2 transmission. SARS-CoV-2 does not survive for prolonged periods on most surfaces and is inactivated by hospital-grade disinfectants through routine cleaning processes. Health care settings should follow the Provincial Infectious Diseases Advisory Committee’s  Best Practices for Environmental Cleaning for Prevention and Control of Infections in All Health Care Settings.
      • Health care facilities should have sufficient environmental cleaning resources to ensure a safe and clean environment and should have protocols in place for both routine cleaning and disinfection, and cleaning and disinfection for patients with COVID-19.
      • No changes in environmental cleaning protocols are required specific to patients with known VOC infection as compared to patients with NVSC2.
    • Leadership, Education, and Training: In health care settings, it is recommended to use a safety coach where staff practices are inconsistent in high risk areas of suspected or confirmed COVID-19 patients. Education and training of staff on routine practices and additional precautions on COVID-19–specific policies and procedures is critical.
    • Multiprong IPC and Public Health Measures: In health care settings, basic measures should be implemented to prevent nosocomial COVID-19 including universal masking, physical distancing, and hand hygiene.


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.