Australia and Canada have joined a growing list of countries requiring travelers from China to take a COVID-19 test prior to boarding their flight, as China battles a nationwide outbreak of the coronavirus after abruptly easing restrictions that were in place for much of the pandemic.

Australian health authorities said Sunday that from Jan 5. all air travelers from mainland China, Hong Kong, or Macao will need to show a negative COVID-19 test taken within two days of their departure.

Canadian authorities announced similar measures that will also come into effect on Jan. 5 in a statement dated Saturday — a move experts say isn’t very effective.

Kerry Bowman, assistant professor at the University of Toronto’s Temerty Faculty of Medicine, said the requirement is “not based on science at this point.”

“This isn’t the early days of the pandemic,” he said. “It’s pretty clear that point-of-entry screening is not very effective at all. Often people can test positive days and weeks later.”

Dr. Isaac Bogoch, associate professor at the University of Toronto’s Temerty Faculty of Medicine, said it’s not entirely clear what the policy’s goals are, but such measures have not helped.

“We know from the past that very focused and targeted travel measures such as this don’t do much to prevent the spread of COVID, either by importing COVID to Canada or by the threat of variants of concern in Canada,” he said.