Random testing at Canada’s borders has no way to distinguish between people who have had the COVID-19 virus in the past and those who are currently infected with it, the government said in a statement.

The mandatory measure, which affects about 1 in 20 fully vaccinated people entering Canada by air, also results in healthy travelers being quarantined.

The PCR or molecular tests used are too sensitive to distinguish active infection from previous infections.

Nevertheless, the government insists on using these tests because it claims that they are the “gold standard” for detecting the virus, even if they can identify people who have fully recovered from it.

According to the government, about 5,000 people are tested each day. The tests are conducted by several private companies, which have received government contracts worth hundreds of millions of dollars since the pandemic began.

Random testing has been widely criticized this spring as a source of unprecedented disruption at Canadian airports. 

To avoid potential problems, including forcing people with past infections into unnecessary isolation, anyone who provides a positive PCR test taken at least 180 days before entering Canada is exempt from the random testing program.

However, over the past year, access to PCR tests has been limited in many places, so it is unlikely that over-infected travelers will be able to provide the evidence needed to obtain an exemption.