OTTAWA -- Canada's national panel of vaccine experts says the second COVID-19 vaccine dose can be delayed briefly in a bid to get more people a first dose faster.

The National Advisory Committee on Immunization says every effort should be made to follow the 21-day and 28-day dosing schedules recommended for the two vaccines approved in Canada to date.

But as the pandemic heats up and vaccine supplies are slow to trickle in, they say delaying the second dose up to six weeks, instead of three or four, could more quickly get at least some protection against COVID-19 to more people.

Canada is getting enough vaccine doses to vaccinate the vast majority of Canadians by the fall but the bulk of that won't happen until later in the spring and summer and provinces are warning they're going to run out of doses.

Almost 550,000 doses have now arrived in Canada and about 71 per cent of them injected, with another 380,000 doses scheduled to arrive by the end of the week.

Clinical trials on the Pfizer-BioNTech and Moderna vaccines both showed the first dose provided some protection against serious illness from COVID-19, but the majority of patients in both trials received a second dose on schedule, leaving very limited data on how long the protection from the first dose lasts.

This report by The Canadian Press was first published Jan. 13, 2021.