VANCOUVER -- Doses of Pfizer’s COVID-19 vaccine are safe and nearly 91 per cent effective, according to details of the company's own study released Friday.

The news comes as more than 62,000 children in B.C. are already pre-registered for vaccine appointments.

The company study tracked 2,268 children aged five to 11. They were given two shots of vaccine three weeks apart of either a placebo or the low-dose vaccine.

Each dose was one-third the amount given to teens and adults.

Sixteen children who were given placebo shots contracted COVID-19, compared to three cases among vaccinated children, according to Pfizer.

No severe illnesses were reported, the company said, but those who were vaccinated had much milder symptoms.

Because more than twice as many children in the trial were given the vaccine than placebo, that equates to better than 90 per cent efficacy, Pfizer said. The study also suggested children developed coronavirus-fighting antibody levels just as strong as teens and young adults who got regular-strength vaccinations.

Dr. Brian Conway, medical director of the Vancouver Infectious Diseases Centre, described the study results as “very good news.”

“We now know that it is as effective in this age group in preventing COVID as it has already been demonstrated to be in clinical trials and in widespread use in all other age groups throughout the world,” Dr. Conway said.

One limitation of the trial, according to Conway, is the sample size. He says it’s too small to detect any serious and extremely rare side effects, such myocarditis – inflammation of the heart.

A recent study by the Ottawa Heart Institute was retracted after overestimating cases of the side effect from an mRNA vaccine at one in 1,000 patients.

Infectious disease specialist Dr. Isaac Bogoch said current estimates are actually “about one in 6,000 to one in 25,000.”

Still, Dr. Conway said it’s important parents understand the risks and benefits of getting children vaccinated.

“In Canada if we vaccinated two million children aged five to 11, there is going to be between 35 and 50 cases of myocarditis caused by the vaccine, we know that,” he said. “But if we don’t vaccinate them in that age group, we are expecting, over the same period of time, 400 to die of COVID.”

In addition, Dr. Conway said the risk of developing myocarditis is likely reduced in younger children.

“We already know that it is less in children aged 12 to 15 than it is in children 16 to 19 so we might expect that at its highest, it will be equivalent to that in the younger teenagers," he said.

Pfizer’s pediatric vaccine is still being reviewed by Health Canada, though Canada is already set to receive 2.9 million doses.

Health Canada’s chief medical advisor Dr. Supriya Sharma said it’s not a done deal yet.

“Kids are not just little big people, they have their own considerations,” Dr. Sharma said. “We wouldn’t authorize it unless it met the rigorous standards that we have to make sure that the benefits outweigh the risk.”

B.C. parents can pre-register children for vaccination appointments online ahead of the shot being approved.

As of Friday, the province said there are 62,438 registrations for children between the ages of five and 11, adding there are approximately 350,000 people in B.C. who are or will be in that age group in 2021.

With files from The Associated Press