TORONTO -- Canada's National Advisory Committee on Immunization (NACI) is now recommending that children aged 12 and older be given the same two-dose regimen of the Pfizer COVID-19 vaccine as adults.

Canada's chief public health officer, Dr. Theresa Tam, announced the updated recommendation at a press briefing on Tuesday.

"NACI says a complete series of two doses of the Pfizer-BioNTech COVID-19 vaccine can be offered to individuals 12 to 18 years of age who are eligible to receive the vaccine," Tam said.

According to the update, NACI recommends adolescents 12 years of age and older "without contraindications to the vaccine" be offered the two-dose shot.

NACI noted that the new recommendation for children was based on Health Canada’s authorization following the results of Pfizer-BioNTech’s Phase 3 clinical trial involving 2,260 adolescents aged 12 to 15.

Conducted in the United States, the trial found the vaccine to be 100 per cent effective in children aged 12 to 15, up from the 95 per cent efficacy shown after the second shot in the trials with older age groups.

Health Canada previously noted that some provinces have already provided COVID-19 vaccines to this age group, if they were children at high risk.

Health Canada’s chief medical adviser Dr. Supriya Sharma said in May that Pfizer’s COVID-19 vaccine has been thoroughly reviewed and is safe for use in the younger age group.

"While younger people are less likely to experience serious cases of COVID-19, having access to a safe and effective vaccine will help control the disease's spread to their family and friends, some of whom may be at higher risk of complications," Sharma said.

"It will also support the return to a more normal life for our children who have had such a hard time over the past year," she added.

Despite NACI's new recommendation, whether or not children will be receiving the shot anytime soon is up to individual provinces and territories as the focus of the majority of vaccine rollouts in Canada has been on those 18 years and up.

In Ontario, youth between the ages of 12 and 17 will be able to book an appointment for their first dose of the Pfizer vaccine beginning May 31, while provinces including Alberta, Saskatchewan and Manitoba has already opened their booking systems to this age group.

The two-dose Pfizer vaccine was the first COVID-19 vaccine to be authorized by Health Canada. It was given the regulatory green light in December 2020 and was the first COVID-19 vaccine to be administered in this country.

Other authorized COVID-19 vaccine manufacturers are also conducting trials with their vaccines in children, and it’s likely over time other vaccines in use in Canada could start being offered to younger people.

With files from's Rachel Aiello