Regulators should reach a decision about whether to approve Canada's first COVID-19 vaccine for infants and preschoolers in coming weeks, federal officials said Friday as the United States prepared to roll out tot-sized shots.

Deputy chief public health officer Dr. Howard Njoo said that Health Canada continues to review Moderna's application for a vaccine to protect children between six months and five years old.

"We anticipate a decision in the coming, I would say, weeks or so. I can't give you a precise date," Njoo told a virtual press conference. "Obviously, they need to do their due diligence."

On Friday, U.S. regulators authorized Moderna's and Pfizer-BioNTech's vaccines for the youngest kids, setting the stage for doses to be doled out next week.

Canada has yet to authorize a vaccine for its nearly two million children under five.

Moderna's shot is the only vaccine for this cohort that has been submitted for regulatory review, Njoo said. Moderna has applied for its vaccine to be given in two doses, each a quarter of its adult dose, given about four weeks apart.

A Pfizer Canada spokeswoman said in an email that the company is making progress on its vaccine submission, but couldn't provide a timeline on when it would be filed.

Pfizer-BioNTech's Comirnaty vaccine can be used on kids as young as five, and Moderna's Spikevax shot has been approved for children ages six and up.

Compared to adults, children face a lower risk of severe COVID-19 outcomes, but that risk isn't zero, said Dr. Katharine Smart, president of the Canadian Medical Association.

In recent months, many of the children treated in hospital for COVID-19 have been ineligible for vaccination, said Smart. As the prospect of a potential seventh wave looms, she said Canada needs to extend the benefits of vaccination to the youngest members of its population.

"We know that children under five have had no protection from COVID. There's many parents, of course, that are very concerned," said Smart.

"We don't know what we're facing in the fall. So I think being able to protect those youngest children is going to be critical."

Canada's chief public health officer, Dr. Theresa Tam, told reporters Friday that indicators suggest the spread of COVID-19 is stabilizing at a national level, and rates of severe illness are declining in most jurisdictions.

While officials are "cautiously optimistic," said Tam, there are signs of increased viral activity in some areas. And new Omicron subvariants -- including BA.2.12.1, BA.4 and BA.5 -- appear to be more contagious and better at evading immunity than their predecessors.

"We do not expect our progress to be linear," Tam said. "Therefore, maintaining readiness for a potential resurgence that could result in severe impacts is our best advantage as we head into summer."

Also on Friday, the federal government discontinued the COVID Alert app. The app was launched in the summer of 2020 as a way to alert people if they'd been in close contact with someone who had been infected with COVID-19, without collecting personal data.

The app was criticized as being ineffective and not living up to expectations. While 6.89 million people had downloaded it as of Feb. 1, the latest federal figures say it recorded only 63,117 positive COVID-19 test results.

This report by The Canadian Press was first published June 17, 2022.

-- With files from The Associated Press and Laura Osman in Ottawa