Vaccine mandates have been blamed for some of Pearson airport's chaos. Is it time to drop them?

The waning effectiveness of vaccines to stop the spread of the highly infectious Omicron variant of COVID-19 could mean it's time for federal policy makers to consider lifting vaccine mandates, some experts suggest.

"It's hard to really justify our mandates anymore," said Dr Zain Chagla,  an infectious diseases physician at St. Joseph's Healthcare Hamilton and an associate professor at McMaster University.

Toronto's Pearson International Airport has recently been a scene of snarling air passenger traffic, causing long lineups and major delays. 

While government officials have blamed staffing shortages for problems, some industry groups and politicians are laying the blame on COVID-related border restrictions including vaccine mandates that require travellers to prove their vaccine status using an app before entering Canada.

Scientists stress that the vaccines do hold up against what matters — severe illness, hospitalization and death.

And Chagla said that when the Alpha and Delta variants of COVID-19 swept through, data showed that vaccination had a "profound effect"  on stopping a significant amount of infections, and that people's ability to transmit was reduced.

But the vaccines' abilities to prevent transmission of the virus changed with the Omicron variant, he says. 

Last month, in a editorial for The Globe and Mail, under the headline: "The logic behind vaccine mandates for travellers no longer holds," Chagla wrote that with the Omicron variant, vaccine efficacy "wanes significantly" to help prevent transmission. He pointed to data from the UK Health Security Agency that he said showed the effectiveness of two or three doses of vaccine against spreading the Omicron-variant infection over time approaches zero.

"We live in a world now where a lot of people have either been vaccinated or got COVID, that maybe one to two per cent of people isn't in that category," he told CBC News. "Are we really working hard to make sure that they're not able to access a flight?" he said.

"They're not necessarily at an increased risk of transmission as compared to the fully vaccinated person against the next variant."

WATCH | Frustrations mount over delays at Toronto's Pearson International Airport:

Proof-of-vaccine certificates to enter public places have been largely removed in all provinces Canada. The remaining proof-of-vaccination policy requirement applies to federally regulated employees and for travel especially by air overseas and to enter Canada. 

However, the Public Health Agency of Canada recently announced that COVID-19 restrictions at the border will remain in place for at least another month. Those restrictions include vaccine mandates, which require travellers to use the ArriveCan mobile app to download proof of their vaccination before entering Canada.

Those who do not are subject to testing and quarantine.