Meeting 43 of the CSA COVID-19 Expert Panel

As part of the response to the COVID-19 pandemic, the Chief Science Advisor of Canada created the Expert Panel on COVID-19 to advise her on the latest and most relevant scientific developments. This information assists the Chief Science Advisor in providing current, cross-disciplinary and independent advice to the Prime Minister and government.

Overview of discussions

Held by MS Teams on April 30, 2021

 

The following discussion reflects evidence and scientific knowledge up April 29, 2021.

Summary

  • The objective of this meeting was to discuss the safe easing of restrictions and re-opening of the economy.
  • Vaccine coverage alone is not necessarily a good metric for the impact of easing restrictions, hospitalization rates also need to be considered. The target threshold for herd immunity is not yet clear and may evolve over time.
  • Efforts to vaccinate as much of the population as possible may need to continue.
  • Schools and long-term care facilities should be prioritized for safe re-opening and rapid testing could be a useful tool to facilitate this.
  • The case for mandatory COVID-19 vaccination in children is complex, as the benefits they derive from the vaccines are mostly indirect.

Participating experts

  • Mona Nemer PhD, Chief Science Advisor of Canada (chair)

Disease modelling

  • Caroline Colijn PhD, Simon Fraser University
  • Daniel Coombs PhD, University of British Columbia

Risk and behavioural sciences

  • Daniel Krewski PhD, University of Ottawa
  • Kim Lavoie PhD, Université du Québec à Montréal
  • Steven Taylor PhD, University of British Columbia

Biomedical and clinical sciences

  • Eleanor Fish PhD, University of Toronto
  • Joanne Langley MD, Dalhousie University
  • Salah Mahmud MD, PhD, University of Manitoba
  • Allison McGeer MD, Mount Sinai Hospital, University of Toronto
  • Samira Mubareka MD, Sunnybrook Research Institute
  • Caroline Quach-Thahn MD, Université de Montréal
  • Supriya Sharma MD, Health Canada
  • Cara Tannenbaum MD, Université de Montréal, Health Canada Departmental Science Advisor

Participating guests

  • Vivek Goel MD, University of Toronto
  • Rosa Stalteri MSc, CanCOVID Network

Other

  • Lori Engler-Todd MSc, Office of the Chief Science Advisor (support)
  • Vanessa Sung PhD, Office of the Chief Science Advisor (support)
  • Priya Gurnani PhD, Office of the Chief Science Advisor (support)

Managing reopening

Key areas of concern were discussed with respect to a safe re-opening strategy, including increased vaccination rates, appropriate metrics for easing lockdown, the role of rapid testing, and relevant contexts for mandatory vaccination.

Behavioural science considerations

  • People are naturally motivated by things that directly benefit them and avoid those that do not. Emphasizing the beneficial outcomes that will result from everyone getting vaccinated while acknowledging that there are no guarantees, can help people make informed decisions.
    • The most challenging public health measure identified by respondents as part of an iCARE StudyFootnote 1 was not being able to gather with friends and family. An emphasis in messaging on the benefit of high vaccination rates to facilitate a return to social gatherings may be helpful.
  • Government benchmarks for re-opening could give people a collective goal to work towards and may improve adherence to public health measures. It is more difficult for people to make sacrifices without knowing the goal they are striving to reach.

Increasing vaccination rates

  • Given the uncertainties around emerging variants of concern and vaccine effectiveness (e.g., preventing infection vs preventing severe disease), herd immunity is a moving target. Rather than aiming for a percentage of the population, a better goal may be to encourage vaccination of all eligible individuals.
    • An improved understanding of the transmissibility of variants of concern would provide better insight into the required vaccine coverage.
    • In the current context, if restrictions are lifted once 75% of the adult population is vaccinated, there will likely be a wave of infections hitting young people. Because they will not get very sick, and because testing is predominantly limited to symptomatic cases, the virus could circulate relatively undetected.
  • Vaccination intent is a matter of evaluating the risk of disease versus the risk from the vaccine. The goal should be to help Canadians make informed vaccine decisions, acknowledging their concerns, given the rapidly evolving data (or lack thereof in some cases).
    • There has been significant media attention around the potential side effects of the vaccines, and confusing/contradictory public health communication. This has created some level of vaccine anxiety among the public.
    • More emphasis is needed on the positive outcomes of getting vaccinated and what could happen if people do not get vaccinated (depending on where they live, chances of getting COVID-19 can be very high).
    • Ultimately, the best outcome is for people to feel good about their decision to get vaccinated based on all the information they have.
  • Vaccine hesitancy is not the same as “anti-vax”; there are individuals who are well-informed, but are uncertain about the COVID-19 vaccine. This is part of the population on the fence that is a “soft yes” to the vaccine, and whose opinion tends to fluctuate with media reports.
  • With improved vaccine supply, efforts will need to balance encouraging uptake of the first dose and increasing rates of second doses among those who are hesitant.
  • Data on vaccine effectiveness after the first dose in Canada is currently sparse. Experts noted that preliminary data (not yet peer-reviewed) suggest that one dose of vaccine is approximately 67% effective for preventing infection by the current virus strain.

Criteria, metrics, and strategies for re-opening

  • Indicators for re-opening are not solely related to vaccination rates, but also relate to the capacity of the healthcare system (e.g., if 75% vaccination coverage is reached and intensive care units are still full, it would not be advisable to lift measures).
  • Positivity rate has limitations because it depends on the number of people being tested.
  • A plan for a gradual re-opening and easing of measures would provide an opportunity to observe and learn in the event that infection rates rise. Non-pharmaceutical interventions, protective behaviour, testing, contact tracing, and vaccinations would need to continue.
  • The priority populations to consider for re-opening should be young people and long-term care residents who have lost all social contact. Available resources such as rapid testing should be directed to schools and long-term care facilities.
  • Israel (55% of population fully vaccinated)Footnote 2 and the UK (68% of adults having received one dose)Footnote 3 can serve as models of comparable societies in informing how to re-open and what to expect.

The role of testing in easing restrictions

  • While vaccines are capturing a lot of public attention, testing will also need to be a part of the re-opening strategy.
  • Rapid testing is a powerful tool that could play a role in easing lockdown and re-opening in certain contexts.
    • Rapid tests are useful in rural and remote areas where there is limited access to PCR tests.
    • Rapid tests could be useful in large gatherings. For example, at-home rapid testing was recently used in an NBA game in the United States where tickets included the price of the test and the attendees self-tested before going to the gameFootnote 4.
    • Rapid tests are useful in outbreaks and in the context of high community spread and could be selectively deployed.
  • Health Canada recently issued an “Authorization with Conditions” for its first single use at-home molecular test (LUCIRA™ CHECK IT COVID-19 Self-Test) which can be purchased without a prescriptionFootnote 5.

Considerations for mandatory COVID-19 vaccinations in schools

  • In Canada, to date, no government has implemented mandatory vaccination for COVID-19 for children in schools. For the purposes of safely re-opening schools, it is worth considering whether and in what contexts mandatory COVID-19 vaccination might be appropriate from a scientific perspective.
    • The benefits of mandatory vaccination would have to be weighed against the potential ethical/legal issues raised and the challenge of achieving very high levels of vaccination among the general population (e.g., 90%) in order to facilitate safe re-opening of schools.
  • At the current vaccination rate, it is expected that teenagers will be vaccinated by the time they return to school in the fall of 2021.
  • While mandatory childhood vaccinations historically have been effective at encouraging high levels of uptake, mandating COVID-19 vaccinations in children is a complex issue.
    • It is not yet known whether long-COVID affects children. Ongoing studies will provide more insight in the future, but data so far suggests that the majority of children generally do not get very sick from COVID-19. In addition, vaccine benefits for children may be largely indirect (i.e., benefits the adults and family members around them and society in achieving herd immunity). This is a different situation from vaccinating against a severe childhood disease where the health benefit to the individual is obvious.
    • On the other hand, COVID-19 has had a significant social and mental health burden on children, including the loss of in-person education, socialization with their friends and families, indoor sports, and an absence of regular day-to-day activities that could have long-term impacts on the development of some children and youth. Measures that accelerate the reopening of society would greatly benefit them.
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