Canada on Wednesday approved the use of the Pfizer-BioNTech Covid-19 vaccine in children aged 12 years and up, becoming the first nation to do so. "This is the first vaccine authorized in Canada for the prevention of Covid-19 in children and marks a significant milestone in Canada's fight against the pandemic," Health Canada chief medical advisor Supriya Sharma told a news conference.

"We are (also) the first in the world to authorize Pfizer for ages 12 to 15," she said, adding that Britain and the European Union are expected to soon follow after reviewing the same testing results submitted by the manufacturer.

The United States will also reportedly authorize the Pfizer-BioNTech vaccine for use in 12-15 year olds as early as next week.

Data from a clinical trial in the United States involving more than 2,000 youths who were given two doses of the vaccine showed it is as safe for adolescents as it is for adults, Sharma said.

There were no cases of Covid-19 recorded among the vaccinated children, according to a Health Canada statement. In adults the Pfizer shot has been shown to be at least 90 percent effective in preventing infection.

The most common reported side effects such as a sore arm, chills or fever were also found to be similar to those in older ages.

The Pfizer-BioNTech vaccine was authorized in December for use in Canadians 16 and older.

Other manufacturers of the four vaccines authorized in Canada -- the others are AstraZeneca, Johnson & Johnson and Moderna -- are conducting or planning their own studies in children as young as six months old.

Sharma said Health Canada will expedite reviews of those results.

Since the start of the pandemic, about 20 percent of all Covid-19 cases in Canada were recorded in people under the age of 19. 

As of Wednesday, nearly 1.25 million people in this country have been diagnosed with Covid-19. More than 24,000 died. 

About 13 million Canadians or 35 percent of the population has so far received at least one vaccine dose.

While younger people are less likely to experience serious illness from Covid, Sharma said, "having access to a safe and effective vaccine will help control the disease's spread to their families and friends, some of whom may be at higher risk complications."

"It'll also support the return to a more normal life for our children who've had such a hard time over the past year," she said.

Sharma also further clarified health authorities' recommendation that Canadians should take whichever Covid vaccine is offered to them first, after a government advisory panel sparked confusion this week by ranking jabs according to safety.

"Each vaccine will have its advantages and disadvantages. The goal," she said, "is to get as many people vaccinated as soon as possible."

Very rare but serious blood clots occurred in a handful of cases among millions who received the AstraZeneca and Johnson & Johnson vaccines. Two new deaths were reported in Alberta and New Brunswick provinces this week, bringing Canada's total clotting deaths linked to the AstraZeneca vaccine to three.

Canadian officials have said the risk of dying from Covid-19 is significantly higher than the likelihood of experiencing fatal vaccine complications.