Moderna seeks COVID vaccine approval for kids under 6 in Canada

Moderna says it's working on a submission to Health Canada for the approval a COVID-19 vaccine for children under the age of six.

The biotech company on Thursday asked U.S. regulators to authorize low doses of its vaccine for children between six months and five years of age.

The long-awaited move is another stride towards potentially opening shots for millions of tots by summer.

In Canada, Moderna says it hopes to complete the application for regulatory approval of its COVID-19 vaccine, Spikevax, "shortly."

To date, Health Canada has only approved mRNA COVID-19 vaccines for children over the age of five.

• 'More questions than answers': COVID vaccines for kids under 5 still not authorized in Canada
• Full COVID-19 coverage at ctvnews.ca/coronavirus

The Pfizer-BioNTech vaccine, Comirnaty, is available for children aged 5 to 11, and Moderna Spikevax is available for children six to 11 years old. About 41 per cent of Canadian children in this cohort have had two shots according to federal data.

Frustrated families are waiting impatiently for a chance to protect the littlest kids as all around them people shed masks and other public health precautions -- even though highly contagious coronavirus mutants continue to spread.

Already about three-quarters of U.S. children of all ages show signs they've been infected at some point during the pandemic.

In Canada, federal data states 10.8 per cent of reported cases were in children up to 11 years old.

Moderna submitted data to the Food and Drug Administration that it hopes will prove two low-dose shots can protect babies, toddlers and preschoolers -- albeit not as effectively during the Omicron surge as earlier in the pandemic.

"There is an important unmet medical need here with these youngest kids," Dr. Paul Burton, Moderna's chief medical officer, told The Associated Press. Two kid-size shots "will safely protect them. I think it is likely that over time they will need additional doses. But we're working on that."

Now, only children ages five or older can be vaccinated in the United States, using rival Pfizer's vaccine, leaving 18 million younger tots unprotected.

Moderna's vaccine isn't the only one in the race. Pfizer is soon expected to announce if three of its even smaller-dose shots work for the littlest kids, months after the disappointing discovery that two doses weren't quite strong enough.

Whether it's one company's shots or both, FDA vaccine chief Dr. Peter Marks said the agency will "move quickly without sacrificing our standards" in deciding if tot-sized doses are safe and effective.

While questions are swirling about what's taking so long, Marks pointedly told lawmakers earlier this week that the FDA can't evaluate a product until a manufacturer completes its application. In a statement Thursday, the FDA said it will schedule a meeting to publicly debate Moderna's evidence with its independent scientific advisers but that the company still must submit some additional data. Moderna expects to do so within weeks.

"It's critically important that we have the proper evaluation so that parents will have trust in any vaccines that we authorize," Marks told a Senate committee.

If FDA clears vaccinations for the littlest, next the Centers for Disease Control and Prevention would have to recommend who needs them -- all tots or just those at higher risk from COVID-19.

"It's very important to get the youngest children vaccinated" but "moving quickly doesn't mean moving sloppily," said Dr. Philip Landrigan, a pediatrician and public health expert at Boston College. FDA must "see if it's safe. They need to see if it's effective. And they need to do so swiftly. But they won't cut corners."

Many parents are desperate for whichever vaccine gets to the scientific finish line first.

"We've been kind of left behind as everybody else moves on," said Meagan Dunphy-Daly, a Duke University marine biologist whose six-year-old daughter is vaccinated -- but whose three-year-old and 18-month-old sons are part of Pfizer's trial.

The family continues to mask and take other precautions until it's clear if the boys got real vaccine or dummy shots. If it turns out they weren't protected in the Pfizer study and Moderna's shots are cleared first, Dunphy-Daly said she'd seek them for her sons.

"I will feel such a sense of relief when I know my boys are vaccinated and that the risk of them getting a serious infection is so low," she said.

The FDA will face some complex questions.

In a study of kids ages six months through five years, two Moderna shots -- each a quarter of the regular dose -- triggered high levels of virus-fighting antibodies, the same amount proven to protect young adults, Burton said. There were no serious side effects, and the shots triggered fewer high fevers than other routine vaccinations.

But the vaccine proved between about 40 per cent and 50 per cent effective at preventing symptomatic COVID-19 during the trial. Burton blamed the Omicron variant's ability to partially evade vaccine immunity, noting that unboosted adults showed similarly less effectiveness against milder Omicron infections. While no children became severely ill during the study, he said high antibody levels are a proxy for protection against more serious illness -- and the company will test a child booster dose.

"That's not totally out of the realm of what we would have expected," said Dr. Bill Muller of Northwestern University, who helped with Moderna's child studies. "Down the road I would anticipate it's going to be a three-shot series."

Another issue: So far in the United States, Moderna's vaccine is restricted to adults. Other countries have expanded the shot to kids as young as six. But while Moderna has filed FDA applications for older kids, too, the FDA hasn't ruled on them. Months ago the agency cited concern about a rare side effect, heart inflammation, in teen boys, a concern that hasn't been reported in much younger children.

It's not clear if FDA will consider Moderna's vaccine for children of all ages now or focus first on the littlest. But Muller already has had lots of parents ask why shots were being tested in tots before older kids -- and says pediatricians and pharmacists must be ready with answers.

Burton said safety data from millions of older children given Moderna vaccinations abroad should help reassure parents.

While COVID-19 generally isn't as dangerous in youngsters as adults, some do become severely ill or even die. About 475 children younger than five have died from COVID-19 since the pandemic's start, according to the CDC, and child hospitalizations soared at Omicron's peak.

Yet it's not clear how many parents intend to vaccinate the youngest kids. Less than a third of children ages five to 11 have had two vaccinations, and 58 per cent of those ages 12 to 17.

-- With files from The Associated Press

This report by The Canadian Press was first published April 28, 2022.