REGINA -- Doses of AstraZeneca’s COVID-19 vaccine will be headed into the arms of Saskatchewan residents in the coming weeks.

The province plans to use the AstraZeneca vaccine for second doses only. Dr. Saqib Shahab, the province’s chief medical health officer, said the optimum time for the second dose of AstraZeneca is 12 weeks after the first, so there is still some time to go as most first doses of the shot were given at the Regina drive-thru clinic in mid-March.

Health officials were previously considering using the Pfizer vaccine as second doses for residents who received the AstraZeneca vaccine because of uncertainty surrounding the supply. 

The province said Tuesday that more AstraZeneca doses have now arrived in the province, so those who got it as a first dose should have access to it for a second dose.

“There's good evidence now to support second doses with AstraZeneca. We have supply available – up to 20,000 doses at present and more in the pipeline. So there will be AstraZeneca available for second doses,” Dr. Shahab said.

Officials said they will consider using other vaccines as a second dose for the AstraZeneca vaccine as additional scientific evidence emerges. Dr. Shahab said the province is waiting on antibody data to see if a second dose of Pfizer mounts the same immune response as a second dose of AstraZeneca.

“We still need some more information to see if those who may want a second dose Pfizer if that's as good as a second dose AstraZeneca or not,” Dr. Shahab said.

Scott Livingstone, CEO of the Saskatchewan Health Authority (SHA), said the health authority has started to open up second doses of the AstraZeneca vaccine to some immunocompromised and vulnerable people – who have been notified by the health authority by mail.

Almost every Saskatchewan resident is expected to have access to a second shot by the end of July. Currently, residents are eligible to book their second dose if they are age 80 or older or if they had their first dose before March 1.

The SHA said it is expanding the booking system and will be working with pharmacies to try and help vaccinate the senior population quickly.