Vaccine experts and infectious disease specialists are urging provinces to move faster to start getting second doses into arms in Canada, particularly for seniors and people with high-risk health conditions.
"We definitely need to get a move on," said Dr. David Naylor, co-chair of the national immunity task force, in an interview with The Canadian Press.
"I think there are compelling reasons to be picking up the pace on second doses."
Almost 20.5 million Canadians have received at least their first dose as of Thursday, but fewer than two million of those have been fully vaccinated with both required doses.
Canada delayed second doses up to 16 weeks in March, on the advice of the National Advisory Committee on Immunization, because vaccine supplies were so scarce.
The strategy has worked to a point, with more than half of Canadians now having at least one shot, and evidence from the United Kingdom that delaying Pfizer-BioNTech and Oxford-AstraZeneca 12 weeks produced stronger immune responses in the end.
While most provinces are setting their own vaccine markers for reopening the economy, chief public health officer Dr. Theresa Tam wants one-fifth of eligible Canadians to have both doses, and 75 per cent to have at least one, before provinces consider loosening restrictions on outdoor activities.
Canada is likely to get to 75 per cent with one dose by June 21, but one-fifth with two doses is harder to gauge. Canada would have to triple the number of second doses it gives every day, immediately, to get there by Canada Day.
Second doses are slowly increasing. Even a week ago, fewer than one in 10 shots given went to a second dose. In the last two days it has exceeded 15 per cent.
But it's not fast enough for some.
Naylor cited a new study from Public Health England this week which showed two doses of Pfizer-BioNTech or Oxford-AstraZeneca were two or three times as effective than just one dose at preventing a symptomatic infection of COVID-19 from two common variants, B.1.1.7 and B. 1.617.2.
He said there isn't data yet that shows how sick people were getting if infected after one dose, which will make a difference in how troublesome the news is to Canada.
Naylor also said seniors who have been waiting the longest for their second dose, who have been the most cautious about their activities and warned their immune systems aren't as strong after just one dose, also deserve to have their second appointments moved up.
