The U.S. State Department is now urging Americans to "reconsider travel" to Canada due to what the Centers for Disease Control call "high" levels of COVID-19 infection.
The new Level 3 travel advisory, issued today, marks a quick end to a three-week period when the warning to would-be travellers to Canada had been eased to "exercise increased caution."
That Level 2 advisory coincided with Canada's decision to allow fully vaccinated U.S. citizens and permanent residents back into the country.
There was no specific reason given for the revised advisory beyond the CDC's notice, also issued today, which pegs Canada's current COVID-19 levels at "high."
Only about 61 per cent of eligible Americans are fully vaccinated, compared with nearly 75 per cent of Canadians over the age of 12.
The U.S. is maintaining its existing restrictions on non-essential Canadian travellers until at least Sept. 21, citing the ongoing spread of the Delta variant of COVID-19.