Pfizer has submitted preliminary research to Health Canada on the effectiveness of its COVID-19 vaccine in children aged five to 11.
The drugmaker confirmed Saturday it provided the initial trial data to the federal department for review as it prepares to make a formal submission seeking authorization to use the product in children.
Pfizer said its formal submission could come later this month.
Health Canada said in an email that Pfizer submitted the preliminary data for children aged five to 11 Friday afternoon, which was earlier than expected. The department said it expects the formal filing of the company's submission in mid-October.
Pfizer Canada spokeswoman Christina Antoniou said the submission will be a request for full authorization.
She said the new drug submission process for COVID-19 vaccines offers the same flexibility as the interim order authorization pathway did, including allowing the company to submit a rolling submission.
"In other words, [it's] not an emergency use authorization but a full approval under which we would continue to submit new data as it becomes available," Antoniou said in an email.
Pfizer's vaccine was initially given the green light for use in Canada last December under an interim order authorization and received full approval last month.
The two-shot vaccine, developed in partnership with German pharmaceutical company BioNTech, is currently available for those aged 12 and older.
The company is testing a lower dose of the shots in children.
Pfizer and BioNTech said last week that researchers found the vaccine antibody responses in children were just as strong as those found in teenagers and young adults getting regular-strength doses.
The companies submitted the research to the U.S. Food and Drug Administration last week and plan to request emergency use authorization of their vaccine in children ages five to 11 "in the coming weeks." The companies also plan to submit data to the European Medicines Agency and other regulators.
In addition, research involving even younger children is also taking place.
Pediatric studies evaluating the safety and efficacy of Pfizer's COVID-19 vaccine in children aged six months to age five is ongoing, with initial results expected before the end of the year, Antoniou said.
Meanwhile, Health Canada approved the use of Moderna's COVID-19 vaccine in kids as young as 12 in late August.
The American drugmaker is also in the midst of vaccine trials for children younger than 12, with results expected sometime this fall.
This report by The Canadian Press was first published Oct. 2, 2021.
— With files from The Associated Press.
Brett Bundale, The Canadian Press