OTTAWA: Canada's drug regulator has approved Johnson & Johnson's single-dose COVID-19 vaccine, the fourth such vaccine to be given the green light, a government source said on Friday.

The official announcement will be made later on Friday, said the source, who requested anonymity given the sensitivity of the situation. Health Canada approved the Pfizer-BioNTech and Moderna Inc vaccines in December, and AstraZeneca's vaccine in February.

Canada ordered more doses of the vaccines per capita than any other country, but so far deliveries have been slow, and it is lagging many other developed nations' vaccination campaigns. Ottawa says deliveries should increase significantly in the second quarter.

If the J&J vaccine has been approved, it could ease some logistical challenges. The vaccine is administered in a single dose and can be stored in normal fridges while the Pfizer-BioNTech and Moderna shots must be kept in freezers.

So far, 4.2% of the Canadian population has received at least one dose of a coronavirus vaccine, according to volunteer-run tracking site COVID-19 Tracker Canada. In the United States, more than 16% have received at least one dose.