A health-care worker does a test at a drive-thru COVID-19 assessment centre at the Etobicoke General Hospital in Toronto on Tuesday, April 21, 2020. Ontario is reporting 153 new cases of COVID-19 and four new deaths related to the novel coronavirus. THE CANADIAN PRESS/Nathan Denette

Easier, quicker saliva sampling eyed for next stage of COVID-19 testing

Saliva collection could capture infections in people who otherwise would not be tested but should be

A saliva-based COVID-19 test is likely to be available this fall, say private and public health officials touting various methods under consideration across the country as lineups grow at COVID-19 assessment centres and cases emerge in newly reopened schools.

Public Health Ontario’s chief of microbiology and laboratory science lists several issues to be resolved before broad provincial use but expects saliva collection will soon make it easier to detect infection, especially among children and others unable to tolerate a nasopharyngeal swab.

“I do foresee it being an option in the near term,” Dr. Vanessa Allen said in a recent interview.

“We’re aiming in the space of weeks to months. Sometime later this fall looks very probable.”

While not as accurate as the gold standard method — in which a long, flexible swab is inserted deep into the nostril — saliva collection is easier, meaning this approach could capture infections in people who otherwise would not be tested but should be, says Allen.

To be clear, these are not the at-home saliva tests that generate an immediate result, but lab-based tests that use the same molecular analysis to detect novel coronavirus in a nasopharyngeal sample.

Essentially, the only difference is the type of specimen being collected.

In that regard, the sample is no easier or quicker to analyze because it requires essentially the same trained lab personnel, machinery and chemicals used for traditional methods — some of which were subject to global supply chain issues early in the pandemic.

However, at the collection stage, saliva-based detection could preserve high-demand health resources and supplies, such as personal protective equipment and nurses, says Dr. Jenisa Naidoo, chief scientific officer at the testing and laboratory firm Dynacare.

Naidoo says the company has developed a proven technique that is 98.4 per cent as accurate as the standard nasopharyngeal method.

It allows patients to collect their own specimen, thereby avoiding close contact with a public health nurse who would need PPE.

“So you have preservation of the PPE, you also don’t need the skilled health-care worker to take that sample, which they would do with the nasopharyngeal swab. And you also don’t have a dependency on that swab, that we actually had a shortage of,” says Naidoo, whose study did not test the method on children.

“The patient can literally spit into a vial or tube and you can use that method versus having a swab stuck into their nose or going into their throat.”

It’s also designed to use standard, widely available tubes, which can be found in any laboratory and does not require Health Canada approval, adds a Dynacare spokesman.

The Brampton, Ont.-based Dynacare, which has 231 locations in Manitoba, Ontario and Quebec, says it is developing plans for “the initial rollout with all of our stakeholders in both government and private industry.”

“Given our experience and scale, this will take place first in Ontario,” says spokesman Mark Bernhardt, who adds Dynacare is ramping up capacity by adding staff and equipment.

“The next steps are to optimize our process to permit high-throughput testing using automation. We are hoping to eventually offer saliva collection to the broader public.”

Allen calls Dynacare’s study “quite good.” It tested 432 patients, who provided saliva and nasopharyngeal samples between June 3 and Aug. 1. The nasopharyngeal samples missed four positive cases and the saliva test missed three.

“I think it will be an acceptable method; we need to make sure that we’ve done all the due diligence so that it performs as well as possible,” she says, noting that includes ensuring the main labs can handle saliva.

Canada’s chief public health officer acknowledged Tuesday that multiple places across Canada are investigating the potential of saliva to detect COVID-19 and hinted at efforts to ensure the option is available coast-to-coast.

“We are just trying to look at those results, and standardizing them as well,” said Theresa Tam.

A spokeswoman for British Columbia’s Provincial Health Services Authority acknowledges the province is “looking into alternate collection methods as part of its test planning for the fall” but would provide no details.

One saliva-based approach that seems well-positioned for a national rollout comes from researchers at The Ottawa Hospital and University of Ottawa in conjunction with the National Microbiology Lab in Winnipeg.

It employs a saliva collection kit designed by Kanata, Ont.-based DNA Genotek comprised of a small collection tube with a small funnel at the top. The device is awaiting Health Canada approval for use beyond research purposes.

A study led by cancer surgeon Dr. Stephanie Johnson-Obaseki, who was inspired by her previous work on a spit test for HPV, used the device to collect saliva and nasopharyngeal samples from 1,939 people who visited the Ottawa hospital with either mild or no symptoms of COVID-19.

Johnson-Obaseki says 34 people tested positive with both methods, but 22 tested positive with the swab test alone and 14 tested positive with the spit test alone. The results were published Aug. 28 in Annals of Internal Medicine.

“So each test missed some,” says Johnson-Obaseki, a head and neck cancer surgeon at The Ottawa Hospital, who notes no COVID-19 test is perfect.

She says the findings raise questions about whether different tests may be more suitable at different times of a person’s illness.

“More research will have to be done to drill down when each test is the best to use.”

Meanwhile, Public Health Ontario is focused on logistical issues — Allen says some sites have tried urine containers to collect saliva, but at high volumes this “takes up too much space in a lab.” The microbiologist-in-chief at Toronto’s Mount Sinai Hospital adds they’re simply too big for his lab’s machinery.

Dr. Tony Mazzulli also dismisses containers that come with a stabilizing liquid as too expensive to be worthwhile.

Allen admits there is much to sort out.

“We’re collaborating with colleagues in B.C. to look at how we can get the best container to hold it,” says Allen. ”So it’s very practical, perhaps not-so-exciting stuff.”

Then there’s the amount of saliva required. Allen says initial experiments needed as much as five millilitres — basically a full blood tube container.

“That actually takes quite a while (to fill) so now there’s a lot of work on trying to get smaller volume,” she says.

“It’s a tradeoff — you want the best test and you want to make it as easy as possible.”

For months now, Mazzulli has received saliva samples from patients who find nasopharyngeal swabs — as well as less-invasive nasal and throat swabs — too painful or difficult.

He questions whether saliva collection would alleviate staffing or resource demands, noting patient information must still be documented and patients need direct instruction to do it right.

“If you truly want to do it properly, people are supposed to let the saliva pool in their mouth for several minutes before they spit in the container,” says Mazzulli, adding that if a nurse is present for this step, they would definitely need PPE.

“So now they’re going to be sitting there waiting five or 10 minutes because they’re trying to accumulate saliva so you’re getting true liquid and not just the foamy, dry spit so to speak. That could slow things down rather than speed things up.

Nevertheless, public demand for more testing options is clearly on the rise and with COVID-19 cases rising as flu season approaches, various provincial and public health leaders have voiced their commitment to boosting test capacity.

Allen doesn’t expect saliva-collection to become the new standard, but does believe it can make getting a test faster and easier.

“It would still not be the collection method of choice for very sick individuals — we would still retain the gold standard,” she says.

“But again, it’s thinking of innovative ways to make sure that people can get their tests and that there’s no kind of real or perceived impediment to getting that test.”

Cassandra Szklarski, The Canadian Press

Like us on Facebook and follow us on Twitter.

Want to support local journalism? Make a donation here.

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

The Dupras family has been regulars at the Babine River and have seen plentiful grizzlies over the years. (Jay Dupras photo/Lakes District News)
A family’s close encounter with a grizzly on Babine River bridge

Photo-enthusiasts let the bear access the bridge for photos putting others at risk

The Burns Lake RCMP is investigating the incident. (Phil McLachlan photo)
Fatal collision between a pedestrian and train near Burns Lake

Police say the investigation is still ongoing

Stikine provincial election candidates (clockwise from top left): Nathan Cullen, NDP; Darcy Repen, Rural BC Party; Rod Taylor, Christian Heritage; and Gordon Sebastian, BC Liberals.
‘Where is Annita McPhee?’: Cullen under fire from opening salvo of all-candidates forum

Four Stikine candidates spar during online debate from Prestige Hudson Bay Lodge in Smithers

(Wet'suwet'en Access Point on Gidimt'en Territory Facebook screenshot)
Ceremony a right at proposed CGL pipeline drill site: BC Union of Indian Chiefs

Indigenous land defenders cannot be criminalized and targeted, argues UBCIC

(File graphic)
Man dies in Gitlaxt’aamiks (New Aiyansh) after being taken into police custody

IIO and BC Corners Service conducting independent investigations

Working smoothly together on May 11, 2020, health minister Adrian Dix, B.C. Liberal health critic Norm Letnick, provincial health officer Dr. Bonnie Henry and sign language interpreter Nigel Howard. (B.C. government video)
COVID-19 co-operation a casualty of B.C.’s pandemic election

NDP’s Horgan weaponizes senior care, B.C. Liberal Wilkinson calls for ‘wartime economy’

The official search to locate Jordan Naterer was suspended Saturday Oct. 17. Photo courtesy of VPD.
‘I am not leaving without my son,’ says mother of missing Manning Park hiker

Family and friends continue to search for Jordan Naterer, after official efforts suspended

A bear similar to this black bear is believed responsible for killing a llama in Saanich on Oct. 19. (Black Press Media file photo)
Vancouver Island residents warned to watch livestock, pets after bear kills llama

Officers could not track the bear they feel may not fear humans

Bernard Trest and his son Max, 10, are concerned about B.C.’s plan for students in the classroom. He was one of two fathers who filed a court application in August to prevent schools from reopening if stricter COVID-19 protections weren’t in place. That application was dismissed last week. (Contributed photo)
B.C. dad pledges to appeal quashed call for mandatory masks, distancing in schools

Bernard Trest and Gary Shuster challenged health, education ministries’ return-to-school plan

RCMP crest. (Black Press Media files)
RCMP cleared in fatal shooting of armed Lytton man in distress, police watchdog finds

IIO spoke to seven civillian witnesses and 11 police officers in coming to its decision

Join Black Press Media and Do Some Good

Pay it Forward program supports local businesses in their community giving

A 34-year-old man was treated for a gunshot wound in Williams Lake Monday, Oct 19, 2020. (Angie Mindus photo - Williams Lake Tribune)
Williams Lake man treated for gunshot wound after accidental shooting: RCMP

Police are reminding residents to ensure firearms are not loaded when handling them

A injection kit is seen inside the newly opened Fraser Health supervised consumption site is pictured in Surrey, B.C., Tuesday, June 6, 2017. THE CANADIAN PRESS/Jonathan Hayward
B.C. records 127 fatal overdoses in September, roughly 4 each day

Vancouver, Surrey and Victoria continued to see the highest numbers of overdoses

Investigators work at the Sagmoen farm in Silver Creek. - Image credit: Observer file photo.
Sex workers allegedly called to farm of Okanagan man convicted of assault, RCMP investigating

Curtis Sagmoen, convicted in relation to assault of sex trade workers, is prohibited from soliciting escorts

Most Read