OTTAWA -- The president of Pfizer Canada says when the company signed a purchase agreement last August it didn't expect its vaccine to get approved here until February.

Cole Pinnow also told the House of Commons health committee on Monday that changes to the dosing schedule and conflicting advice could make more people vaccine hesitant.

Last week, the National Advisory Committee on Immunization, or NACI, recommended spreading out the second dose of all COVID-19 vaccines from three or four weeks, to four months. The advice came because real-world data on one dose shows it is highly effective and more people could get vaccinated with one dose sooner while vaccines are in short supply.

One of the reasons for that, said Pinnow, is because when Canada signed a contract on Aug. 1 to get the vaccine, it believed the vaccine wouldn't get approved here until well after the New Year. The United Kingdom and United States saw a chance to get the vaccine authorized before Christmas and planned their deliveries accordingly, he said.

"It wasn't until mid-November that we identified a pathway that would allow us to bring this product to Canadians in December," he said. "Ever since then, we have been working to accelerate delivery to this country."

Pinnow said when the first doses were delivered Dec. 14, Canada was the second major country in the world to receive them, and it was "almost two months earlier than originally anticipated."

Pfizer was to ship four million doses between January and March. The company was able to ship 255,000 doses in December, and Pinnow said Pfizer will increase its deliveries by the end of March to 5.5 million doses.

More than 1.8 million Canadians have now received a single dose of vaccine, and with deliveries coming in faster, the number of people vaccinated each week has gone up.

But Canada remains behind many of its peers, with the U.K. having vaccinated more than one in three people, the United States more than one in four, and much of Europe at least one in 12.

Canada has vaccinated about one in 20.

The slow rollout last week prompted NACI's advice to delay the second dose up to four months and most provinces are heeding the recommendation.

It should mean every adult Canadian gets one dose before Canada Day, rather than the original plan of Sept. 30.

But Pinnow said Pfizer remains steadfast that its clinical trials only show how well the vaccine does if given in two doses 21 days apart. The trials said the doses were 95 per cent effective against COVID-19.

He said that is also how Health Canada authorized the vaccine to be used and worries the conflicting advice between government authorities "creates concern, confusion and potentially hesitancy from certain people within Canada."

Conservative health critic Michelle Rempel Garner asked Pinnow if NACI had contacted Pfizer before issuing the four-month guidance, and Pinnow said no.

Rempel Garner said that was an unexpected answer.

"That's frightening," she said.

The U.K. has delayed the second dose of Pfizer by 12 weeks, and a study in Scotland suggested the first dose of both Pfizer and Oxford-AstraZeneca had a profound effect on hospitalizations and deaths of people over 80.

British Columbia and Quebec reported significant improvements in the pandemic's affect in long-term care homes after most residents received their first dose in January and February.

Canada is the only country to suggest delaying the second dose by four months. All provinces have said they intend to follow the four-month recommendation.

MPs at the health committee also pushed Pinnow on the secrecy of the Pfizer contract, which has been kept entirely out of the public eye.

He refused multiple times to divulge any details of the contract, including how much Canada is paying per dose, or whether Canada had to pay more to get its doses delivered earlier than planned.

Pinnow said releasing the contract details will not do anything to get vaccines into Canada faster.

This report by The Canadian Press was first published March 8, 2021.