Canada gave the green light Thursday for children age 5-to 11 to receive the Prizer-BioNTech two-dose vaccine.

Health Canada said the decision -- children under 12 will be given one-third of the vaccine quantity of those over that age -- is a giant step in battling the virus.

“This is the first COVID-19 vaccine authorized in Canada for use in this age group and marks a major milestone in Canada's fight against COVID-19,” Health Canada said in a statement. “After a thorough and independent scientific review of the evidence, the department has determined that the benefits of this vaccine for children between 5 and 11 years of age outweigh the risks.”

Those risks include rare cases of myocarditis - inflammation of the heart muscle - but that must be weighed against the fact that up to a quarter of children who end up in hospital for the virus go into intensive care. Health Canada found the evidence to support the vaccine in younger children was more beneficial than risky.

The government announced the approval at a press conference Thursday.

Health Canada said clinic trails showed the efficacy of the Pfizer vaccine to be 90.7% in the 5-to 11 age group. In those 12-to 15, it was 100% effective and in those 16 and older, 95%, as reported by CTV News.

The National Advisory Committee on Immunization recommended the interval between doses be increased to 21 days from the standard two weeks, since study shows that the longer period improves the protection from the virus.

The approval comes as Canada continues to wrestle with COVID-19, at times seemingly winning only to find the virus once again up and fighting off attempts to dispel it.

So far, close to 30,000 Canadians had died from the virus. Since the first infection was confirmed Jan. 25, 2020, there have been a total of 1.76 million COVID-19 cases.

Probably the province considered most under siege from the virus is Alberta, with 383 new cases as of Thursday, five more deaths active cases of 5,384, with outbreaks in 187 schools. Hospital emergencies are so overloaded that some patients have been flown to Ontario for treatment. Alberta made the mistake of giving carte blanche to businesses to open this past summer, health officials said.

In all, as of Thursday, 78.3% of Canadians have had at least one dose of vaccine, and 75% have received two, according to CBC vaccine tracker statistics./agencies