Wednesday, February 8, 2023

Canada, US warn against sore throat test for at-home COVID-19 rapid test

TORONTO – As the Omicron version of COVID-19 spreads, provinces are continuing with rapid at-home tests designed to detect the virus from nasal swabs.

In an emailed statement to, Health Canada says that medical devices such as rapid test kits should be used only as directed by the manufacturer. The agency says provinces and territories have the ability to authorize health products for “off-label” use, but so far, no provincial or regional public health authority is recommending throat swabs.

There have been several reports on social media that people are testing positive from throat swabs after testing negative through nasal swabs. These anecdotes have been shared with millions of views through TikTok videos and . has been extended with hashtags on twitter,

The Israeli health ministry is recommending swabs for both the throat and nose, albeit against the manufacturer’s recommendation. In the UK, some tests distributed by the National Health Service indicate both throat and nose swelling.

The US Food and Drug Administration has warned against using throat swabs. Agency tweeted last friday, “Fact: When it comes to at-home rapid antigen #COVID19 tests, those swabs are for your nose and not your throat.”

The advice for strangulation is based on some early research suggesting that the omicron variant may be more detectable in the throat. A study from South Africa posted online on Christmas Eve found that nasal swabs were most accurate in detecting the delta version of the virus. But for Omicron, nasal swabs could only detect virus 86 percent of the time, while saliva samples detected virus 100 percent of the time. The study is a pre-print, which means it has yet to go through a peer review process.

Experts are also divided on the use of throat swabs. Dr. Matthew Augton, an infectious diseases specialist at McGill University, explains that the home tests currently available in Canada are increasingly based only on nasal swabs and not evaluated with swabs from other sites.

“As they say in the military, ‘You go to war with your army, not the army you want,'” he told in an email last week. “We have (rapid home testing) those that are being deployed and will be used. It is important to understand their best use and their fundamental limitations so that they can interpret what they are telling us.”

Augton also noted that rapid tests are already more likely to cause false positives than PCR tests.

“I would advise caution in relying on anecdotal reports when it comes to turning up recommendations on testing.”

However, Dr. Colin Furness, an epidemiologist at the University of Toronto, believes that given the evidence that Omicron behaves differently, health officials should provide clear instructions on how to treat sore throats for rapid home tests. be used.

“The tests are much less sensitive to the front of the nose. But there has been no public education about self-cleansing the throat,” he told in an email last week. “It is vitally important that this guidance be developed if we are to continue to rely on rapid tests as a screening tool.”

With files from Kristie Somos and Sonja Puzik of


Nation World News Desk
Nation World News Desk
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