The company on Tuesday started a mid-to-late stage study of its vaccine to assess the safety and effectiveness of two doses of the shot, given 28 days apart, and intends to enroll about 6,750 children in the United States and Canada.
In a separate study, which began in December, Moderna is also testing its vaccine in adolescents between 12 and 18 years old.
Moderna’s vaccine has already been authorized in Canada and the U.S. for those who are aged 18 and older. But experts don’t expect to see any approvals for children in the near future.
When asked whether Health Canada could approve a vaccine for use in children before school begins in the fall of 2021, Dr. Supriya Sharma, the agency’s chief medical advisor, said the timeline sounded “a bit optimistic.”
“So the trials in children tend to be a bit slower to get up and running in terms of recruiting individuals,” she said earlier this month. “And then, of course, we have to conduct the trials and then take that information and assess that.”
She said it’s “not inconceivable that we might have some data in the summer.”
“And potentially by the end of this calendar year, we might have some indications in children, but … that’s still pretty optimistic.”
That appeared to be echoed by Dr. Caroline Quach, the chair of Canada’s National Advisory Committee on Immunizations, on Tuesday. She said data has so far been provided by Pfizer-BioNTech on its vaccine being tested within the 12 to 15 age group.
However, she said NACI will not make any recommendations on vaccines used in children before it has seen data from a phase three trial, she said.
“From our understanding, we should get some data in the next two to three months for at least eh 12 to 15-year-olds. Then, as data is accrued and vaccines are deemed to be safe and immunogenic, then they will decrease in age range until they go down to the younger ones,” she said.
“But we’re not expecting anything for children before the end of 2021.”
At this point in Canada, no vaccines have been approved for use in children younger than 16 years of age.
The Pfizer-BioNTech vaccine can be used in anyone 16 and older, Health Canada says, while the other three shots — Moderna, AstraZeneca, and Johnson & Johnson — have been approved for adults 18 and up.
Health Canada says it is waiting on data from the vaccine manufacturers before it approves any shot for use in children.
Sharma said Pfizer and Moderna’s clinical trials in younger-age adults are the furthest along so far, but acknowledged that Johnson & Johnson has also been given Health Canada’s seal of approval to test the safety and efficacy of its vaccine in children aged 12 to 17.
AstraZeneca has also started its own clinical trial to test its vaccine in younger age groups, though Sharma is convinced Health Canada will receive data from Pfizer and Moderna first.
Children have so far fared better than adults throughout the COVID-19 pandemic. The virus is considered far deadlier for adults — particularly seniors and those with pre-existing conditions — but has proven to be generally very mild in the young, with minimal to rare deaths.
The result has essentially put kids near the end of the line for vaccinations. It’s also sparked a debate among scientists and other officials about how important it is to get children immunized.
So far, the rollout of vaccines worldwide has prioritized older people and others at risk because of their health or occupation.
Dr. William Schaffner, an infectious diseases expert from Vanderbilt University, said it’s important vaccine makers are testing their precious drugs in children.
He put it simply: “First of all, they’re not at zero risk.”
“There have been seriously afflicted children in this country and around the world, so we want to protect them,” he said.
“Second, children can be transmitters. They can carry the virus, bring it home, and transmit it among themselves. Not as freely and exuberantly as influenza, but nonetheless, they can do that.”
Schaffner said it’s important to test the vaccines in segmented age groups — like 12 to 15 years old — because it helps “get the dose right.”
“We want to make a careful assessment of all the safety issues, as well as the effectiveness,” he said.
Schaffner believes adding childhood or student vaccination to Canada’s vaccination strategy could add confidence to school safety plans and “lower the risk even further.”
— with files from Global News’ Hannah Jackson and Reggie Cecchini