OTTAWA -- The 1.5 million doses of the AstraZeneca vaccine on loan from the U.S. can now be administered to Canadians, following Health Canada’s assessment of the batch itself and the manufacturing site where it originates.

Maj-Gen. Dany Fortin said on Thursday that deliveries to provinces are already underway.

Canada has purchased 20 million AstraZeneca doses coming from the U.S. Another two million is being sent from the Serum Institute in India and another 1.9 million from COVAX, a global vaccine sharing network designed to assist mostly middle to low-income countries.

The news comes just days after the National Advisory Committee on Immunization changed its recommendation to advise suspending use of the vaccine in those under the age of 55, due to the possibility of blood clots.

“When a new potential safety concern or adverse event following immunization is brought to our attention, thorough examination and assessment occurs to determine if the event is related to a vaccine. If necessary, prompt, appropriate action is taken,” said deputy chief public health officer Dr. Howard Njoo on Thursday.

Asked whether the change in guidelines impacts vaccine hesitancy, Njoo said he understands Canadians could feel confused -- but for the most part, he said, the drug remains safe.

“If you look overall, I would say that the AstraZeneca vaccine is safe and effective. You know, 20 million doses plus have been administered worldwide and only a few of these very rare side effects have been reported, ” he said.

Canada has already received 500,000 doses of the AstraZeneca vaccine from India, but concerns mounted last week when India hit pause on international exports in order to fulfill domestic orders as cases soar. Canadian health officials maintain the supplier will fulfill its order, but have no indication of when the next shipment will be sent.

"We are working with the company on determining when the doses will arrive. We are expecting a delay in the shipment but they are committed to meeting their contractual obligations," said Joelle Paquette, from the department of Public Services and Procurement, adding that Canada will receive its first delivery from COVAX next week.

The government is facing heightened pressure to get vaccines in the arms of Canadians as quickly as possible, amid a new round of shutdowns to curb the growing spread of the virus and its variants.

The federal government estimates that nearly 9.5 million doses will have been distributed to provinces and territories by the end of the week. Starting next week, Pfizer-BioNTech will start sending one million doses a week until the end of May. The government maintains the country is on track to obtain 44 million vaccine doses by the end of June.

More than 13 per cent of Canadians have received at least a first dose of a COVID-19 vaccine.