Pfizer-BioNTech says vaccine is safe and effective in children

Pfizer and BioNTech says trials of the companies’ Covid-19 vaccine, now known as Comirnaty, have produced a “robust” immune response in children aged five to 11.

In a Monday news release, the companies said their trial showed the vaccine is safe and effective when children are given in two doses, 21 days apart. The dose used is 10 micrograms, a third of that received by people aged 12 and over.

“We are eager to extend the protection afforded by the vaccine to this younger population, subject to regulatory authorization, especially as we track the spread of the Delta variant and the substantial threat it poses to children,” said Pfizer chair and chief executive Albert Bourla in a statement.


The companies said they would now share the results with regulators, including Health Canada, which will complete an independent scientific review of the evidence before deciding whether to authorize the vaccine’s use in younger children.

The trial included 2,268 children. Two-thirds received the vaccine while the remainder received a saltwater placebo.

Since children are less likely to become very sick from Covid-19, researchers weren’t able to conclude how effective the vaccine is in preventing Covid-19 or hospitalization. Instead, they compared the level of protective antibodies in children to those seen in adults and teens.

Side effects of the vaccine at the lower dose in children are comparable to side effects seen in people aged 16 to 25, trial researchers concluded.

Monday’s results were published directly by the companies and have yet to be peer-reviewed or published in a recognized scientific journal.


Pfizer-BioNTech announced results of their earlier study involving teenagers aged 12 to 15 on March 31. Health Canada authorized the vaccine’s use for that age group on May 5. The NWT began vaccinating teens the following day.

Pfizer-BioNTech says the results of another study examining the vaccine’s efficacy in children under five years old, using a three-microgram dose, is expected before the end of the year.