The National Advisory Committee on Immunization says the Johnson & Johnson vaccine should be limited to people over the age of 30 who don't want to wait for Pfizer-BioNTech or Moderna.
The advice is almost identical to that issued for the Oxford-AstraZeneca vaccine last month and comes as both are suspected of causing a new and very rare blood clotting syndrome.
In Canada there have been seven known cases of vaccine-induced thrombotic thrombocytopenia, or VITT, one of them fatal.
As of April 24, 1.7 million people in Canada have been given at least one dose of the AstraZeneca vaccine.
No J&J doses have been injected in Canada thus far, but in the U.S. they have documented 17 cases of the blood-clotting disorder in about eight million doses given.
Canada's first 300,000 doses of J&J are on hold at a Toronto-area warehouse pending investigation to ensure they are safe after discovering they were partly made at an American facility cited for safety and quality-control violations.