Healthcare officials are still looking into the growing number of asymptomatic cases of COVID-19 across Canada, who are known as the ‘silent spreaders’ of the deadly disease. An asymptomatic case can remain feeling perfectly well, while spreading COVID-19 to those around them.

Northwestern Ontario residents received a reminder of how dangerous an asymptomatic case can be as six hospital staff at the Meno Ya Win Health Centre screened positive for COVID-19 over the weekend, but no cases of the illness has been found at this time within the facility, patients or staff.

Reported asymptomatic cases in the region include the six Meno Ya Win staff, two inmates at the Kenora Jail and at least one case in the City of Dryden.

While some residents may feel that the Northwestern Health Unit’s catchment area has seen a large number of asymptomatic cases recently, local healthcare leaders say the same situation is playing out across Canada, leaving healthcare staff searching for answers.

“Right around the world, we’re scratching our heads about the significance of asymptomatic people,” says Acting Medical Officer of Health for the Northwestern Health Unit, Dr. Ian Gemmill. “We are testing lots of asymptomatic people across Ontario, and it’s clear that from time to time, positives will turn up. This is not unique to northwestern Ontario.”

“Maybe someone was infected before and still has some of the virus left, even though they’re no longer infectious. It could be someone who didn’t recognize their symptoms. It could be someone who is incubating the illness and is about to become sick, that’s the person that we really want to get at. That’s the kind of person who might be spreading it to others.”

“It’s a tough question to answer. But I’m so glad that we’re not dealing with a large number of very sick people.”

A small Chinese study suggests that asymptomatic COVID-19 carriers will spread the virus longer than those with COVID-19 symptoms, and other research suggests that symptomatic patients had a more robust immune response to the virus.

“To be truthful, we really don’t know. We’re learning as we go with this particular virus,” explains Public Health Physician with the Sioux Lookout First Nations Health Authority, Dr. John Guilfoyle.

“The symptoms for this disease are wide-spread. They’re everything from respiratory symptoms, to a lack of smell, to skin rashes, diarrhoea and a fever, or just generally unwell. It’s really difficult to nail down.”

A recent study from Nature Medicine suggests that people with asymptomatic infections developed signs of minor lung inflammation, similar to pneumonia, but were not exhibiting any other symptoms.

Technical Lead on the COVID-19 pandemic for the World Health Organization, Maria Van Kerkhove, says the actual rates of asymptomatic transmission are not known at this time.

“The majority of transmission that we know about is that people who have symptoms transmit the virus to other people through infectious droplets,” said Van Kerkhove, during a WHO question and answer period. “But there are a subset of people who don’t develop symptoms, and to truly understand how many people don’t have symptoms, we don’t actually have that answer yet.”

Ultimately, healthcare officials around the world are reminding residents that people who are not showing any symptoms for COVID-19 can still spread the virus, whether they feel ill or not. That’s why social distancing measures and mask wearing is so important until a vaccine is available.

In February, the World Health Organization said the first COVID-19 vaccine wouldn’t be available for 18 months, or roughly by August of 2021. The European Medicines Agency said a vaccine could be approved in roughly one year.

On May 15, the W.H.O. said there were 110 possible vaccines that would be tested in preclinical (non-human) evaluations around the world. One of those vaccines is being tested in Halifax, Nova Scotia. However, during public health emergencies such as the COVID-19 pandemic, Health Canada is able to order special authorizations for vaccines that aren’t yet approved in Canada.

As of June 23, the Northwestern Health Unit has conducted over 8,400 COVID-19 tests in their catchment area, resulting in 36 positive cases. 26 of those cases are now considered as resolved.

If you are experiencing COVID-19 symptoms or feel unwell, you are asked to contact your local Assessment Centre.

For more information:
6 hospital staff screen positive for COVID-19 in Sioux Lookout
Is COVID-19 here to stay?