TORONTO -- Health Canada is reviewing a submission from Pfizer-BioNTech to expand the use of its COVID-19 vaccine in children aged 12 and older.

Health Canada said on Friday that the department is currently reviewing the submission, but did not provide any details on when it may be approved.

Last month, Pfizer said its Phase 3 clinical trials showed its COVID-19 vaccine was safe and 100 per cent effective in 12 to 15-year-olds.

In a statement, the pharmaceutical company said more than 2,200 adolescents participated in the trial.

A total of 18 cases of the coronavirus were identified in the group that was given a placebo shot, but no infections were declared in the group that was given the vaccine, according to Pfizer.

Clinical trials are also underway for both COVID-19 vaccine makers Moderna and Johnson & Johnson in the United States.

Despite showing effective test results in adolescents, the vaccines have not been given approval for use in children in the U.S., according to the U.S. Food and Drug Administration.

Stanford Medicine has expanded Pfizer’s test trials to American children as young as 6 months to 12-years-old, in part of the vaccine’s Phase 3 pediatric trial.

As of Friday, Health Canada has received a total of 15 vaccines submitted for review, only four of which have been granted approval.