This is part of a continuing series of recommendations put out by CoVaRR-Net. These recommendations are directed to the Federal Deputy Minister of Health, local and provincial medical health officers, the Urban Public Health Network, the Variant of Concern Expert Panel, and public health officials.
The current environment of the COVID-19 pandemic is very fluid. Some of these recommendations may soon be out of date.
Given the prominence and transmissibility of the Omicron variant, Canadian jurisdictions are now recommending at-home rapid antigen testing (RAT) for infection control and outbreak management. Given the capacity limitations on PCR testingThe “gold standard” in SARS-CoV-2 detection, it is administered at a clinic or a hospital, using a nose or throat swab, or a gargle and spit method in many provinces, RATs are now a necessary tool for quickly identifying positive cases and limiting onward transmission.
There are limitations to this approach, however, including public health monitoring being compromised, the under-counting of cases and rates, as well as losing out on securing positive specimens for gene sequencing and thereby monitoring the emergence of new variants.
Currently, Canada’s federal and provincial jurisdictions lack a database for the public reporting of RAT results. The reliance on using RATs as both a screening and diagnostic tool without needing to formally report (positive) test results to public health officials skew both clinical and public health case numbers.
Socio-economic inequalities are a substantial challenge, as well. Test uptake has been lower and infection rates higher in lower socio-economic areas, in areas with fewer digital resources or lower digital literacy, and within non-white communities. In some jurisdictions, RATs must be purchased, which creates both a cost barrier and social/health inequities.
The appropriate use of RATs
Evidence, both anecdotal and revealed in a pre-print from South Africa, shows conflicting discussion in public health and research regarding the best way to use RATs. Should they be administered with oropharyngeal (throat) or nasopharyngeal (nasal) swabs?
At the federal level:
- Fund and procure enough RATs for Canadian jurisdictions to disseminate so that all populations can access them at no cost. Encourage different jurisdictions to provide available RATs in gathering places such as schools, public libraries, and city-owned spaces.
- Fund, develop, and build a database to record and disseminate Canada-wide data on provincial RAT results.
- Fund rapid research on the effectiveness of RATs, comparing various ways of conducting the tests, including those done with oropharyngeal (throat) and nasopharyngeal (nasal) swabs. Release guidelines on these comparisons via the Public Health Agency of Canada or Health Canada.
At the provincial and territorial levels:
- Ensure that RATs are used in high-prevalence COVID-19 contexts (i.e., daily seven-day average incidences of COVID-19 greater than 25 per 100,000). RATs can be used for self-screening and isolation when individuals have symptoms or suspect exposure, are completing an isolation period, or are self-monitoring an infection status.
- As much as possible, and as resource capacity allows, complement RATs with rt-PCR tests. The use of RATs for self-diagnosis should be used sparingly and be accompanied by strong provincial directives, be equitably distributed and available to marginalized Canadians, and used alongside a robust rt-PCR testing, tracing, and reporting program.
- Recommend that a positive RAT result require an isolation time of seven days and/or a 48-hour symptom-free period (whichever is longer) for all populations, based on the generation time (i.e., exposure to resolution in a person) of Omicron.
- Develop a formal mechanism to connect at-home test results to provincial public health units. This would ensure that proper contact tracing and isolation protocols are followed, and that a diagnosis is recorded for monitoring and program applications.
At the local and regional levels:
- Support and recommend the use of RATs for asymptomatic screening in the following high-risk settings: congregate living (i.e., homeless shelters), care-home facilities, and hospital/emergency departments.