Sask. has some AstraZeneca doses, is waiting to give out second shots

Premier Scott Moe is telling people not to worry if they got a first COVID-19 shot of AstraZeneca.

The province currently has about 20,000 doses of those shots on hand now, and it’s just waiting for another couple weeks to use them. Health officials have said about 73,000 Saskatchewan residents got AstraZeneca as a first dose.

While the Pfizer and Moderna vaccines can administer a second dose almost anytime between four and 16 weeks, Dr. Saqib Shahab — the province’s chief medical health officer — explained the advantage of waiting for 12 weeks for AstraZeneca.

“Detailed studies, primarily in the U.K. and also in several provinces in Canada, have shown that the efficacy in the clinical trials of AstraZeneca was slightly lower than the mRNA vaccines, but if you wait 12 weeks for the second dose, the efficacy is much higher at 80 per cent, and so it starts approaching the efficacy of the mRNA vaccines,” Shahab said Tuesday.

Shahab said it’s really important for long-term protection.

“The aim of focus and finish, the aim of two doses, is we’re not just looking at the spring and the summer, we want to see a COVID-free fall. That’s why getting AstraZeneca at the optimum 12 weeks will be ideal and preferable,” said Shahab.

The first 15,000 AstraZeneca shots given out in Saskatchewan were at a drive-thru clinic held in Regina in mid-March; it started March 14 for select health-care workers and was opened to people in their 60s over the following week.

It has been between nine and 10 weeks for those people now, which means they’ll be the first to get a second AstraZeneca shot — but they’ll have to wait another couple weeks.

There are some people with compromised immune systems who got AstraZeneca for a first dose who have got a letter saying they’ll be eligible to get their second dose a little earlier.

Concerns have been raised recently about the safety of AstraZeneca, specifically when it comes to blood clots.

Shahab said the rate of blood clots related to the shot is now around 1 in 50,000 people, and there were about 24 cases in Canada, including one in Saskatchewan, where that person recovered. Shahab also said with a second dose, the incidence rate will be lower.

“So there’s good evidence now to support second doses with AstraZeneca,” said Shahab.

For anyone still concerned and who wants to choose Pfizer for a second dose instead, Shahab said health officials are still waiting on guidance from studies that are happening right now.

He explained preliminary data has shown it’s safe, but they’re still waiting on some antibody data to see if using Pfizer as a second dose mounts an immune response as well as using AstraZeneca in those who got the latter vaccine as a first dose.

Saskatchewan Health Authority CEO Scott Livingstone said that if more AstraZeneca is required, then the authority has been assured that it would likely get that vaccine.

When it comes to Pfizer and Moderna, though, Shahab made a point of encouraging people not to wait and to get their second shot as soon as they come eligible.

EDITOR’S NOTE: Due to incorrect information provided, this story had misstated the dates the first AstraZeneca doses were given in Regina. That has now been corrected.