Manitoba now testing some asymptomatic people for COVID-19

The province of Manitoba has quietly started testing people for COVID-19 who aren't showing symptoms to get a sense of where it is spreading through people who are asymptomatic. 

A fact sheet posted on the Shared Health website says public health workers are now doing asymptomatic surveillance to monitor the spread of COVID-19 in people without symptoms. 

"The extent of this asymptomatic or presymptomatic spread is currently unknown. To learn more, swabs are now being collected from people that do not have symptoms to test for COVID-19," the fact sheet says. 

People who are visiting a setting or facility where testing is being conducted will be asked if they want a test, it says. 

"Your participation is voluntary. Your care will not be affected" by the choice to refuse or accept participation, it says. 

Manitoba expanded its testing criteria to cover anyone with symptoms of the virus at the end of April. 

Testing in Manitoba had previously been limited to people who were symptomatic and at risk of contracting or spreading the coronavirus, including returning travellers, front-line health-care workers and first responders, anyone in an intensive care unit or personal care home with respiratory symptoms, and anyone living on a First Nation, in a prison or at a remote location, such as a work camp.

Targeted testing 

Chief Provincial Public Health Officer Dr. Brent Roussin said Friday the province was looking into targeted asymptomatic testing to give the province a sense of whether there are people with COVID-19 in the community that they were unaware of. 

This would be done through sentinel surveillance, where they would randomly select a health-care facility, such as a doctor's office, and offer anyone going there a nasalpharyngeal test, he said. 

The province already does this for influenza during flu season, he said. 

"That's just to get a random sample of community transmission." 

He still doesn't believe widespread testing of asymptomatic people is useful, he said.

"That's not what we're going to do. We're going to do targeted asymptomatic testing on say, those who are high risk, those who are traveling … and then we want to do sentinel surveillance, just do this random selection of Manitobans to get an idea that if the virus is circulating out there that we could pick up early."

The province hasn't been seeing as high a demand for testing as expected, Roussin said, so while he's not encouraging widespread testing of people who don't have symptoms, testing sites won't turn people away. 

"We're not recommending people without symptoms be tested, but if somebody showed up, maybe they had mild symptoms that maybe didn't meet our criteria or they're asymptomatic, we'd still offer them the test and then give them that sheet," he said. 

Roussin didn't know offhand how many tests of asymptomatic people have been completed thus far, but the number of people who have tested positive for the virus who didn't show symptoms has been very low, he said.

Jason Kindrachuk, an infectious disease specialist from the University of Manitoba, believes testing asymptomatic people is significant at this point in time, to get a broader sense of the spread of the novel coronavirus that causes COVID-19.

"We have an idea of how many cases we've seen in different regions of not only Canada, but across the globe," Kindrachuk said while on CBC Radio's Up To Speed.

"But that's only a microcosm of what there likely is."

Most COVID-19 tests conducted have been from people showing symptoms of respiratory illness, or people in high-risk demographics, he explained.

For asymptomatic testing, Kindrachuk says front-line workers such as health-care workers and grocery store clerks would be a good place to start.

Two new cases of COVID-19 in the province were announced Friday, bringing the province's total to 292, with 18 active cases, 267 people who have recovered and seven deaths. One person is in hospital and no one is in intensive care.

An additional 873 laboratory tests were performed on Thursday, bringing the total number of tests performed since early February to 37,272.