Is the notion of asymptomatic spread backed by science?

Is the notion of asymptomatic spread backed by science?

Two minutes with the Justice Centre


‘…instead of cloistering infected people in hospitals to protect a healthy general population, (we) now cloister a healthy general population  at home to protect space in hospitals.’

Canada’s governmental response to COVID-19 is based on the theory that many Canadians may be symptom-free themselves, but infecting others without knowing it; we are all deemed to be asymptomatic spreaders.

The governments’ belief in this theory results in health orders which, instead of cloistering infected people in hospitals to protect a healthy general population, now cloister a healthy general population at home to protect space in hospitals. Thus, millions of apparently healthy Canadians work from home and are ordered to limit social interactions. Restaurants, gyms and all manner of recreational, sporting and entertainment facilities are pushed towards bankruptcy. Airlines are being crippled and, if current trends do not change, international travel will be possible only for the wealthy. Houses of worship have been shut entirely or restricted to such low numbers that they may as well be shut down.

Given how many healthy people are now so ‘cloistered,’ Canadians deserve to know if the cost is worth it.
How many people are actually asymptomatic?
How contagious are they, really?

Given the degree to which the possibility of asymptomatic spread underpins Canada’s lockdown strategy, Canadian data is surprisingly light. But a literature review of 61 learned articles published by the American College of Physicians (Jan 21,2021) concluded that about 30% of people who tested positive for COVID-19, showed no symptoms. (These studies summarized results for about 1.8 million people.) A similar study, (Sept. 2020, PLoS Medicine) put the number lower yet, at 20%. And Alberta suspended asymptomatic testing in October after 233,000 tests found only seven positives in 10,000.

Whether it is 20 %or 30 % would be of little consequence of course, if virus transmission by a person with no symptoms seemed remotely likely.

But, a post-lockdown study in Wuhan last June studied nearly 10 million people and found only 300 asymptomatic cases; of their 1,174 close contacts, none tested positive.
Meanwhile a similar worldwide literature review of 54 studies of household transmission showed asymptomatic carriers infected household members 0.7% of the time, compared to 18% for people showing symptoms.

The evidence therefore suggests that after a year of severe economic and personal distress, fear of asymptomatic transmission can justify neither ongoing lockdowns nor continued infringements of Canadians’ Charter freedoms – with all the attendant and so far uncosted harms that go with them.

Lacking a scientific basis, severe and damaging lockdown restrictions should without delay be replaced by targeted methods to protect the most vulnerable group of Canadians: Seniors in nursing homes.


For more information, see the Justice Centre report:

Flying Blind: Governments’ hasty decisions to lock down Canadians while damaging public health and the economy

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