Saturday, January 16

COVID-19 | Rapid tests could be used “cautiously” in Quebec


(Quebec) The million rapid COVID-19 screening tests that are lying dormant in Quebec are in the process of being used in a “prudent” manner. A committee of experts created by the Legault government recommends gradually deploying, in certain circumstances, these tests which “may have a prominent place in the control of the pandemic”.



Tommy Chouinard
Tommy Chouinard
Press

According to his notice sent to Quebec this week, that Press obtained, these tests could be used in a retirement home where a case has been confirmed, in isolated regions, in screening clinics in order to make a diagnosis in particular in children presenting symptoms, in workplaces and accommodation centers for the elderly in a major outbreak situation and when the analysis laboratories for conventional tests are overwhelmed.

There is no question of using these tests to do a massive screening operation. Thus, their use in schools, businesses or within the general population is one of the “possible scenarios, but not prioritized” by the committee. He “believes, however, that these scenarios could be the subject of a subsequent evaluation before being entirely rejected”.

The Legault government created this committee to guide it in the use of rapid tests approved by Health Canada, which allow a result to be obtained in 15 minutes or less. It has received $ 1.3 million from the federal government, and a further $ 1 million is expected. Ottawa regrets that Quebec still does not use them (except in four regions, but on a very small scale). The Liberal Party of Quebec has been following the Legault government on this subject for weeks and is demanding that rapid tests be used in schools in particular.

There are two types of rapid test technology, one which is based on amplification of nucleic acids (the ID NOW test), the other which detects antigens, which are the surface proteins of the virus responsible for COVID-19 (the Panbio and BD Veritor Plus System tests).

The committee stresses that the technologies of these rapid tests “are less efficient than the tests offered in the laboratory” that have been used since the start of the pandemic.

[Ces tests] may not diagnose up to 30% of those infected [produire un résultat faux négatif], but also generate a diagnosis in the absence of infection by the virus [faux positif], especially when the prevalence of the disease in the test group is low.

Extract from the opinion of the expert committee

The committee recalls that, for this reason, conventional tests analyzed in the laboratory must “remain the test of choice for the management of COVID-19”.

“However,” he adds, “these fast technologies have the advantage of delivering immediate results. Deployed intelligently and cautiously, these rapid diagnostic tests may have a prominent place in pandemic control. ”

Thus, the committee “recommends deploying rapid tests in specific contexts that meet one or more criteria”. For example, when the tests currently used “are not sufficiently available or [que] the time taken to obtain results exceeds 48 hours after the sampling ”. When “the probability of a positive result, depending on the epidemiological context, is known”. Or when rapid tests are likely to “accelerate public health management of outbreaks, contagious cases and their contacts in the community.”

ID NOW

For the ID NOW test, the committee proposes to “gradually deploy it as follows:

“In regions poorly served by aircrafts [actuels]either by lack of laboratory or lack of reagents for other available devices or when the delays in obtaining results are detrimental to public health objectives;

“In designated screening or assessment clinics, particularly in regions where laboratory capacities are already overloaded and where the volume of users guarantees optimal use of these devices;

“For teams dedicated to managing outbreaks in living environments for the elderly, provided that the devices prove to be sufficiently resistant”.

Panbio and BD Veritor Plus System

For the Panbio and BD Veritor Plus System tests, “the proposed deployment scenarios are:

“To accelerate the transfer of users to living environments when the deadlines for test results [conventionnels] exceed 12 hours;

“With marginalized and socially disrupted clienteles who do not use the resources of the health and social services network;

“During major outbreaks in workplaces and living environments for the elderly;

“When demand exceeds laboratory analysis capacities, despite the optimal deployment of ID NOWs”.

Benefits despite their limitations

The committee is cautious in specifying that “rapid tests must be the subject of prior technical and clinical validation before their deployment”. He nevertheless recognizes the benefits despite their limitations. “The speed to take care of [les] positive people and to put their contacts in administrative segregation ”that it is possible to obtain with these tests can in a way“ compensate […] the proportion of infected people not diagnosed due to the poor performance of the test ”. “The committee believes that there are probably gains to offer a rapid test by more quickly capturing the cases and their contacts”, we can read.

In the case of schools, the committee agrees that “some argue that testing students in schools with rapid tests could help determine more quickly whether or not outbreaks are present.” But it raises “operational issues” linked to such an operation: “the time needed to obtain parental consent before proceeding with the test and the availability of professional resources to carry out the tests were mentioned as a brake on such an approach. ”

“In addition, the situation in schools seems under control and fairly well understood. More and more schools are relatively autonomous in the application of the instructions and are even ahead of Public Health when a case is declared to them. Some believe that adding a layer of complexity to the management of classes based on different test results risks reducing the fluidity and effectiveness of current case management. […] The committee therefore does not prioritize the use of rapid tests in schools, but […] a research project aims to validate the approach. ”

The committee is made up of experts from the National Institute of Public Health of Quebec, the National Institute of Excellence in Health and Social Services, the health network, regional public health directorates and representatives of the Ministère de Health and Social Services.




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