User:J S Lundeen/sandbox

COVID-19 testing

COVID-19 testing can be used to track the prevalence and spread, to diagnose individuals for treatment, to identify infections for isolation and contact tracing, to screen at-risk populations, to clear exposed healthcare workers to return to work, and to identify individuals with potential immunity. The World Health Organization says that jurisdictions should aim to test every suspected case of COVID-19. On April 23rd, Trudeau identified broader testing as key to reopening the country, mentioning the target of 60,000 tests per day set by Dr. Theresa Tam, but warned that up to 120,000 per day may be required. As of late April, approximately 20,000 tests per day were being perfomed in Canada. Total numbers of tests conducted for the provinces and Canada show that over 800,000 Canadians have been tested.

Role of the Government of Canada

Federal approval and regulation of diagnostic tests

Only COVID-19 tests approved by Health Canada can be imported or sold in Canada. Since this is usually a lengthy process, on March 18th, Minister of Health Hajdu issued an interim order to allow expedited access to COVID-19-related medical devices for use by healthcare providers, including diagnostic test kits.The same day, the first commercial tests were approved, RT-PCR tests from Roche and Thermo Fisher. Another 13 diagnostic products have since been approved, all based on Nucleic Acid tests. As of April 30, 21 diagnostic device applications were listed as submitted by Health Canada.

National Microbiology Lab

Canada's National Microbiology Lab in Winnipeg performs diagnostic testing for and research into COVID-19. Samples from suspected cases early in the pandemic were sent by provinces and territories to this national lab for testing, either as the sole test or as a check of an in-province test result. The first confirmed case in Canada was diagnosed by the lab on January 25, 2020. Since then, provinces and territories have established their own testing capacity but have occasionally sent samples to the national lab for a second test as a check.

Federal facilitation of testing

Provinces have faced COVID-19 testing backlogs due to a shortage of supplies, including the chemical reagents required to complete the tests. In late April, the federal government arranged for a cargo flight from China that delivered the equivalent of about six to nine months of production for one particular raw material for the 20-odd raw materials needed by supplier LuminUltra to supply reagent kits for RT-PCR machines.

Types of COVID-19 Tests

Virus-RNA tests

Health Canada identifies nucleic acid-based testing as "the gold standard used in Canada and abroad, for the diagnosis of active COVID-19 infection in patients with symptoms." The predominant type of testing used is RT-PCR. In it, a carefully produced and validated swab is used to collect a sample from a person's throat, back of the nose, or front of the nose. The swab is put inside a sealed container containing a medium that preserves the virus, which is sent to test-processing centres in the corresponding province or territory. At the centres, highly skilled technicians use large commercial machines from a variety of manufactures to process batches of tens to hundreds of samples at a time. The test chemically strips the RNA from the sample then mixes it with a test kit containing chemical reagents designed to detect RNA signatures of SARS-CoV-2. The sample is cycled between a set of temperatures to amplify the chemical RNA signature. This leads to processing times that range from 4 to 24 hours. The actual RT-PCR test is 99% accurate. However, false negative results are estimated to occur 8-10% of the time due to poor swabbing technique and might be as high as 30% depending on how long after symptom onset the test was performed.

Provinces have faced COVID-19 testing backlogs due to a shortage of the chemical reagents and swabs required to complete the tests.

Virus-RNA test reagent kits

LuminUltra Technologies Ltd. of Fredericton is producing reagent test-kits to use with automated RT-PCR machines. On April 15th, Trudeau announced that the company would be "ramping up production … to meet the weekly demand in all provinces." The company announced the same day that it would provide "500,000 urgently needed COVID-19 tests per week to the Canadian federal government for use across Canada."

Canadian-made Virus-RNA test systems

A few companies have developed alternate methods to test for the RNA of the virus. These might be faster than laboratory RT-PCR or portable making them useful at border crossings, isolated communities, prisons, and care homes.

Spartan Bioscience Inc. of Ottawa signed contracts with the federal government and the provinces of Alberta, Quebec, and Ontario to supply virus-RNA testing systems that process a single swab sample in 30 to 60 minutes. Together the contracts were for over one million swab test kits, and at least 250 handheld devices. Health Canada approved the test on April 13. While these machines cannot process many samples in total, they have the advantage of being small and easy to use. Thus, they can be used to provide rapid results at the point-of-care

Precision Biomonitoring of Guelph signed a Letter of Intent on March 31st with the federal government to co-develop a novel point-of-care test kit for COVID‑19, which is now pending an authorization from Health Canada. Their 1.2 kg battery-operated mobile device performs nine tests per hour and takes 60 minutes to produce a result.

Bio-ID Diagnostics of Edmonton has developed a direct 24-hour virus test that can be scaled to 20,000 samples per day. Since it is based on sequencing DNA it avoids false positives, and it detects a low concentration of the virus substantially reducing false negatives in asymptomatic individuals.

Serological testing for antibodies

These blood tests look for antibodies to the SARS-CoV-2 virus and range in complexity from laboratory tests to at-home kits similar to pregnancy tests. Antibodies do not form immediately upon infection, so these tests are not well-suited for detecting a current infection. However, they can potentially identify those who have been infected in the past. Health Canada has been evaluating a number of antibody tests but, as of May 1st 2020, has not approved any. Health Canada deemed that "Serological tests are not appropriate for early diagnosis of COVID-19, largely due variability in the time required after infection to develop antibodies."

Research and population immunity

Health Canada posts "studies will be required to determine how long the antibodies remain detectable, whether for weeks, months or years" and "the relationship between antibodies and immunity to future viral infection." Nonetheless, many countries are conducting or planning large-scale testing to determine what proportion of the population has been infected and is potentially now immune. As of April 20, the WHO estimated that at most 2-3% of people in affected countries have been infected. On April 23, 2020, Trudeau created an Immunity Task Force of researchers, including Dr. Tam, Dr. David Naylor, and Dr. Mona Nemer, to coordinate monitoring of immunity and vulnerability to COVID-19 in the Canadian population. The taskforce will oversee national antibody surveys over the next two years in which will test one million Canadians. Researchers at Sinai Health’s Lunenfeld-Tanenbaum Research Institute in Toronto are developing a robotic system that can process mass numbers of antibody tests.

Canadian-made antibody tests

MedMira of Halifax developed one of the first rapid detection kits for HIV and has now developed a COVID-19 antibody test that takes 15-20 min.

Plantform Corp. of Guelph has applied for funding from the National Research Council to develop an antibody test for COVID-19.

Rapid Antigen testing

These test for antigens, proteins that are part of the surface of the virus. Antigens can be detected almost immediately after infection, like nucleic acid-based tests and unlike antibody tests. However, these tests use similar technology to at-home antibody tests, and are rapid, small, and could be mass-produced. Like the nucleic-acid tests, they can use nasal or throat swabs and do not require blood. They have been held up as a solution for achieve mass testing of the population by Dr. Deborah Birx, the White House coronavirus task force coordinator. However, as of April 2020, the WHO estimates that the sensitivity of these tests might vary from 34% to 80% (based the performance of current influenza antigen rapid tests) and writes the "WHO does not currently recommend the use of antigen-detecting rapid diagnostic tests for patient care, although research into their performance and potential diagnostic utility is highly encouraged."

Canadian-made rapid antigen tests

Sona Nanotech of Halifax is developing point-of-care COVID-19 antigen test kits that provide results in 5-15 minutes and is anticipated to cost less than $50. If successful, the project will yield 20,000 test kits available per week, with the potential to scale-up to 1 million test kits per week.