Novel Coronavirus COVID-19
 


Asymptomatic Testing



Tests are most effective when people have symptoms. If someone has no symptoms and gets tested, the test is not as accurate. This means a negative test result could give a false sense of security because the virus could still be in its incubation phase and undetectable.


The incubation period of COVID-19 is 14 days. This means that any time in those 14 days, people could develop symptoms. If someone is tested too early, the test may not be accurate. This means asymptomatic testing cannot rule out a COVID-19 infection. Even if the province was to put a large-scale asymptomatic testing campaign in place, the data may find some cases, but may not find other cases that develop after the person was tested.


A small number of asymptomatic (‘without symptoms’) people may be offered testing on a voluntary basis to better understand COVID-19 transmission patterns in the province. The groups that are offered asymptomatic testing changes as the situation in Manitoba evolves and as we gain better understanding about COVID-19 transmission.


As of late November, Manitoba had conducted more than 340,000 COVID-19 tests. This includes people who have symptoms, people without symptoms but who had been a close contact, and people without symptoms who had no known exposure to COVID-19.

  • Of the 340,000 tests, roughly 66,000 of these tests were asymptomatic tests.
  • Of the 66,000 tests conducted, 2718 of these tests were positive, or 4.11 per cent.

At this time, Manitoba has suspended asymptomatic testing in people without a history of exposure to COVID-19 due to the high positivity test rate and the need to maintain adequate supplies to continue testing of symptomatic individuals. Asymptomatic testing continues to occur in outbreak settings and for close contacts, as well as in a few other circumstances such as on admission to hospitals and personal care homes.

In addition, public health officials have introduced a pilot project around testing in long-term care facilities. The project offers rapid testing for asymptomatic personal care home staff working in three licensed personal care homes. For more information on this pilot project, visit this page.


Voluntary asymptomatic testing was offered to truck drivers, and those in healthcare settings for reasons unrelated to COVID-19.


To be most effective, testing should be done on people who are most likely to have been exposed to COVID-19. This is why we continue to do asymptomatic testing in outbreaks and in contacts, and continue to strongly recommend that symptomatic people, including those with mild symptoms, to get tested. By testing those who have COVID-19 symptoms and those most likely to be exposed, we can track the spread of COVID-19 and maintain our testing supplies.


As we have learned more about COVID-19, testing eligibility has evolved in Manitoba and across Canada to maximize resources and identify cases. Since asymptomatic testing can result in more false negatives, testing only those with symptoms and exposures is the best way to manage our testing supplies and limit the spread of COVID-19.


Test results are significantly more reliable when testing a person with COVID-19 symptoms. Testing those without symptoms can result in false negatives as the virus may be incubating for up to 14 days. Regardless of a negative result, you should stick to the fundamentals (hand hygiene, social distancing, wear a mask and stay home if sick).