"After completing a thorough and independent scientific review of the evidence, the department determined that this vaccine is safe and effective when used in this younger age group," said Health Canada's Chief Medical Advisor Supriya Sharma at a press conference on Wednesday. 

Canada became the first country in the world to have okayed the two-dose Pfizer vaccine shots to the younger age group, the Xinhua news agency reported. 

The Canadian government authorised the vaccine for use in individuals 16 years of age and older last December. 

Health Canada based its decision on data from Phase 3 clinical trial in participants aged 12 to 15 years old. 

The trial enrolled 2,260 adolescents 12 to 15 years of age in the United States. All participants in the trial will continue to be monitored for long-term protection and safety for an additional two years after their second dose. 

"After completing a thorough and independent scientific review of the evidence, the department determined that this vaccine is safe and effective when used in this younger age group," said Sharma. 

"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. "The most commonly reported side effects were temporary and mild, like a sore arm, chills or fever." 

Usually, the vaccine submission review process can take much longer, but because of an emergency order, Health Canada has been able to expedite the authorisation process. 

Health Canada has published a series of documents detailing its decision and a summary of the evidence reviewed. 

Pfizer-BioNTech is required to continue providing Health Canada with ongoing safety and efficacy information as the product is being used in real world settings. 

With nearly 11 million doses sent to Canada to date, Pfizer has committed to sending more than 2 million doses each week, until end of June. 

Asked what this might mean for schools to be able to reopen, Sharma said that will depend on how and when provinces and territories in Canada decide to administer these shots to younger people. 

As of Wednesday noon, Canada reported a cumulative total of 1,253,817 Covid-19 cases, including 24,445 deaths and 130,008 variants, according to CTV.