Recognizing that the question arouses “a lot of debate among experts”, Quebec persists and signs: rapid tests should be used as a priority by people with symptoms of COVID-19. However, “exceptions” will be considered acceptable, for example when visiting an extremely ill person.
“It’s primarily a question of rapid test performance. They perform much better in symptomatic than asymptomatic ones. We have been able to test it in several circumstances, especially in companies where there was this instruction to test asymptomatics. We then saw several false negatives or positives, ”explained the strategic medical advisor to the Ministry of Health and Social Services (MSSS), the DD Marie-France Raynault, during a technical briefing on Thursday.
However, she acknowledges that this “opinion” gives rise to “a lot of debate among experts”. “Rapid tests work when you’re contagious. Contagiousness has nothing to do with the symptoms. The scarcity of resources should not encourage an erroneous argument ”, wrote this week the professor at the School of Public Health of Montreal (ESPUM), Roxane Borgès Da Silva, on Twitter.
Since then, several other specialists, including the former president of the National Advisory Committee on Immunization (NACI), Dr.D Caroline Quach, and McGill Department of Medical Engineering Director David Juncker argued that rapid tests work in asymptomatic people, as long as they carry a high viral load. Several called on Quebec to be transparent with the population, clearly saying that the shortage of rapid tests is the real reason behind this instruction.
“Unnecessary risks”
Marie-France Raynault, she argues that several sources of expertise, including the global and independent network of Cochrane researchers, “continues to say that the sensitivity of rapid tests in asymptomatic is very low.” “There is also a false assurance with a rapid test, which is not as sensitive as a PCR test. People may think they are not at risk of transmitting, and take unnecessary risks, ”said the government official.
PHOTO MARCO CAMPANOZZI, ARCHIVES THE PRESS
The DD Marie-France Raynault
She admits that she “would still make an exception” for a person without symptoms who would have to visit her father “who is very ill”, for example. “Maybe then, to meet someone very vulnerable, we could make an exception. It would be an additional precaution, but it would not exempt you from wearing a mask, and staying two meters away, ”adds Mme Raynault.
Differences between the instructions of the various authorities also seem apparent. Earlier, Thursday, the regional director of public health of Montreal, the DD Mylène Drouin, affirmed that “if a rapid test is positive, you do not need to go to a screening center”.
The MSSS counselor suggests instead “taking a screening test” in a dedicated clinic “if possible”. “If you take a rapid test and you are positive, the urgency is not to go and confirm your test, it is to isolate yourself. Having said that, then it would be desirable for you to confirm it, but there is no rush to do so. Make an appointment. There is no need to queue in a screening center, ”she says. She specifies that it is desirable to be screened in a clinic “for security reasons”, since rapid tests cannot be screened or sequenced, unlike PCR tests.
As for the differences in the instructions, the DD Raynault can be explained by the context of community transmission which differs from one region to another. “In a context of high community transmission like in Montreal, the probability that a rapid positive test is really positive is very high. The probability of having a false positive is therefore lower ”, concluded the DD Raynault, adding however that this possibility “is not null”.
Towards a “self-declaration” platform?
The provincial government is also considering the creation of a digital platform that would allow Quebecers to “self-report” their COVID-19 status, after having passed a rapid test at home. However, nothing would yet be confirmed, the authorities assessing in particular “the reporting bias” that such an exercise could generate. As mentioned on Wednesday by the Minister of Health, Christian Dubé, Quebec is also studying the option of buying its own rapid tests, if the arrivals from the federal government are not sufficient. “There are probably purchases that have already been made,” raised the DD Raynault.