Ontario’s COVID-19 Science Advisory Table is urging people to change the way they use rapid antigen tests after determining the regular nasal swabs are less sensitive to the Omicron variant.
In a new brief released Thursday, the science table warned that a single negative rapid test “cannot reliably rule out infection” and shouldn’t be used as a “green light for abandoning or reducing precautions.”
A regular nasal sample, especially those taken in the first one or two days after infection, are less sensitive to the Omicron variant compared to the Delta strain, officials said.
“What we see based on early results, but very consistently, is that if you just use a swab of your nose, that especially early on during the first perhaps 48 to 72 hours after infection, the sensitivity of the test is relatively low. You won't detect Omicron infection that easily,” Dr. Peter Juni, scientific director of the advisory table, told CTV News Toronto in an interview.
“One of the reasons might be that the distribution of the virus is different than what we saw for previous variants.”
However, the science table says the tests can be more accurate if both cheeks are swabbed, in addition to the back of the tongue or throat, prior to going up the nose.
According to the brief, a nasal sample alone was about 68 per cent effective in detecting Omicron while a combined nasal and throat sample was about 82 per cent.
An instructional video released by the science table on Feb. 7 says that rapid test users should swab the inside of their cheeks, between the cheek and gums while rotating the swab for five seconds.
The video then instructs the user to swab the arch at the back of the mouth for another five seconds “in a circular fashion.”
A gag reflex is normal, officials said, but the process should not be painful.
Finally, users should insert the swab about two centimetres into the nose and gently wipe around the inside of the nostril about three to four times. Then, do the same in the other nostril.
“Stop advancing the swab when slight resistance is felt, even if it is less than two centimetres. No force is needed,” the video says.
The same swab should be used for the cheek, throat and nose.
Juni added that rapid test users should remember to start with the mouth, “otherwise it’s just a bit disgusting.”
If someone does the swab properly and still gets a negative test, the science table warns that it doesn’t necessarily mean the person is clear of infection.
“You still should not rely on a single negative test,” Juni said. “You should repeat tests and have two tests, perhaps 48 hours or more apart.”
A positive result using a rapid test can be considered accurate.
The province is providing free rapid antigen tests to Ontario residents at select grocery stores and pharmacies starting this week.
About 5.5 million tests will be distributed to just over 2,400 sites each week.
Witih files from CTV News Toronto's Colin D'Mello
Thousands of people wearing red and white and waiving Canadian flags packed downtown Ottawa to celebrate Canada's 155th birthday on Friday, while groups of protesters popped up around Parliament Hill to protest COVID-19 vaccines and federal restrictions.
It's been 25 years since Saskatchewan's last residential school closed, but some are still healing.
U.S. President Joe Biden intends to nominate an anti-abortion Republican lawyer to a federal judgeship, two Kentucky Democrats informed of the decision say.
Canada Day has kicked off the unofficial start of summer, and the tourism sector is hopeful the first season in three years largely free of COVID-19 restrictions will marshal a much-needed boost for a pandemic-stricken industry.
A California man has posted a widely-shared video in an attempt to educate people about the monkeypox virus outbreak, to encourage people to get vaccinated if they're eligible and to make it very clear: 'You do not want this.'
When Dan Fine returned from his first trip volunteering at animal shelters on the Polish-Ukrainian border in late April, he immediately felt compelled to return to continue helping pets that have been left behind in the war.
Moving toward reconciliation doesn't come from jumping 'the queue to perfection,' but by building bridges and trusting one another, Canadian singer-songwriter Chantal Kreviazuk told CTV News Channel during Canada Day celebrations in Ottawa on Friday.
In the wake of last year’s discoveries of unmarked graves at residential schools and the prominent displays of the Canadian flag during 'Freedom Convoy' protests, some Canadians are re-evaluating the meaning of the national symbol.
A recent survey shows nearly 50 per cent of Canadians who rent expect to do so forever. As rising interest and inflation rates contribute to a sense of pessimism among first-time homebuyers in Canada, some are sharing their struggles with purchasing their first house.
A prominent housing advocacy group fears Quebec could see an increase in households left without a permanent place to live as leases expire across the province on July 1.
A motorist died after suffering serious injuries in a collision early Friday evening in Quebec’s Montérégie region.
A group of Indigenous people in Quebec expressed disappointment and concern Friday after learning that only 400 seats will be reserved for residential school survivors at the Basilica of Sainte-Anne-de-Beaupré during Pope Francis' visit on July 28.
With his wife Joyce on his arm, Tom Hennessy left Victoria Park in London, Ont. to complete his 100-mile walk to raise money for homeless veterans.
After a two-year break due to COVID-19, the Law Enforcement Torch Run for Special Olympics was back Friday in London.
Close to 1,000 people are at Victoria Park in London, Ont Friday morning for the second annual Turtle Island Healing Walk.
Emergency service workers in the Region of Waterloo kicked off a friendly competition Friday to see which team can donate the most blood by Labour Day.
OPP are trying to identify a man who they say was involved in an "unwanted residential paving incident" in Puslinch, Ont.
Waterloo Region held its first in-person Canada Day celebrations since 2019 and there were several local events for residents to show off their Canadian pride.
Science North and the Sudbury Multicultural and Folk Arts Association held an event showcasing many cultures, traditions and tastes that make up their diverse city.
Hundreds of people lined up for free hot dogs and for fun in the suds in Hollinger Park in Timmins on Canada Day. The event was hosted by the City of Timmins and the Timmins Community Park Association.
The Sudbury Wolves have selected two players from Slovakia in today’s 2022 CHL Import Draft.
Thousands of people wearing red and white and waiving Canadian flags packed downtown Ottawa to celebrate Canada's 155th birthday on Friday, while groups of protesters popped up around Parliament Hill to protest COVID-19 vaccines and federal restrictions.
Emergency crews responded to a collision involving an SUV and a pickup truck at the intersection of Merivale Road and Baseline Road just before 11 a.m. Friday.
With the main show at LeBreton Flats this year instead of Parliament Hill because of construction, the location of the fireworks show has changed, so the usual spots won't get you the best view.
Ontario drivers experienced some relief from record-setting prices at the pump on Friday as the province's gas tax cut came into effect.
With his wife Joyce on his arm, Tom Hennessy left Victoria Park in London, Ont. to complete his 100-mile walk to raise money for homeless veterans.
In the past 24 hours, the Chatham-Kent Police Service responded to 199 calls for service, arresting six people as a result.
Thousands packed downtown streets Friday for the first Canada Day celebration in two years, not restricted by pandemic measures.
Police in Gravenhurst say a man has died after being reported missing.
Two people have been hospitalized with non-life-threatening injuries following an early morning assault in Wasaga Beach.
The spouse of the gunman in the Nova Scotia mass shooting will testify mid-July before a public inquiry, but she won't face direct questions from lawyers representing victims' families.
As Claire Mahaney-Lion dropped her son off at school this morning, she questioned the reasons behind scheduling a school day that would last fewer than two hours.
Saint John is having its dog day. The host city of the 2022 Memorial Cup is celebrating after the Saint John Sea Dogs bested the Hamilton Bulldogs 6-3 in front of a capacity crowd during Wednesday's championship game at TD Station.
Friday marked the first Canada Day in two years without any public health restrictions, which meant Calgarians were finally able to gather at several in-person events across the city.
Members of Calgary’s Vietnamese community gathered Friday at The Journey to Freedom Park to celebrate the unveiling of a meaningful monument.
The Flames lost their longtime organist Friday, when Willy Joosen died.
In-person Canada Day festivities made a return on Friday for the first time since the pandemic started, with residents bringing back old traditions and creating new ones.
A pro-choice rally was held at the Manitoba Legislative Building on Friday -- a week after Roe v. Wade was reversed by the United States Supreme Court.
Officers with the Manitoba RCMP have confirmed that a body was found in the Assiniboine River on Thursday.
It's been almost a year since Kabul's fall and the U.S. withdrawal from Afghanistan. Among the many aspects of Afghan society threatened by the Taliban is the country's rich musical culture.
A former B.C. Mountie is facing discipline for communicating with the sister of a woman found dead in Okanagan Lake.
Marc Diaz is warning others after he spent 11 hours waiting at the Surrey, B.C., passport office this week, only to return to his car and find an $80 ticket – because the adjoining parking lot has a three-hour limit.
From drumming circles, charity runs, to a healing walk, Edmontonians found a way to celebrate their country or reflect on its past in a manner that felt right to them.
An explosive comeback will light up the Edmonton sky Friday night as Canada Day fireworks return to pre-pandemic proportions.
A local beekeeper is asking for help to rescue a colony of honeybees from a junior high school.
© 2022 All rights reserved. Use of this Website assumes acceptance of Terms & Conditions and Privacy Policy