Moderna says vaccine results for kids under 6 are encouraging, will file for authorization soon

Moderna's COVID-19 vaccine works in babies, toddlers and preschoolers, the company announced Wednesday — and if regulators agree it could mean a chance to finally start vaccinating the youngest children by summer.

Moderna anticipates filing for vaccine authorization in Canada this spring for the youngest age group

Clinic volunteer Kelly Brown draws out Moderna vaccine during a clinic at St. Lawrence College in Kingston, Ont., on Jan. 2, 2022. The company is looking to have its vaccine authorized for the only remaining ineligible age group, using a smaller dose. (Lars Hagberg/The Canadian Press)

Moderna's COVID-19 vaccine works in babies, toddlers and preschoolers, the company announced Wednesday — and if regulators agree it could mean a chance to finally start vaccinating the youngest children by summer.

Moderna said in the coming weeks it would ask regulators in the U.S. and Europe to authorize two small-dose shots for youngsters under six. A company representative in an email to CBC News anticipated a similar timeline for Canada.

Early results from the study found that tots developed high levels of virus-fighting antibodies from shots containing a quarter of the dose given to adults — although it was less effective against the super-contagious Omicron variant than prior variants.

"The vaccine provides the same level of protection against COVID in young kids as it does in adults. We think that's good news," Dr. Stephen Hoge, Moderna's president, told The Associated Press.

Parents have anxiously awaited protection for younger kids, disappointed by setbacks and confusion over which shots might work and when. Pfizer is testing even smaller doses for children under five but had to add a third shot to its study when two didn't prove strong enough, leading to a postponement of an already scheduled vaccine advisory committee meeting with the U.S. Food and Drug Administration. Those Pfizer results are expected by early April.

Kids under five are the only age group that aren’t eligible for a vaccine yet. Vaccine manufacturers are working on vaccines for young children, but parents and guardians have a lot of questions while they wait. What do we know about COVID-19 vaccines for kids 5 and under? We find out from Dr. Cora Constantinescu, a pediatrician and infectious diseases physician at Alberta Children's Hospital in Calgary.

Vaccinating the youngest "has been somewhat of a moving target over the last couple of months," Dr. Bill Muller of Northwestern University, an investigator in Moderna's pediatric studies, said in an interview before the company released its findings. "There's still, I think, a lingering urgency to try to get that done as soon as possible."

The younger the child, the smaller the dose being tested. Moderna enrolled about 6,900 kids under six — including babies as young as six months — in a study of the 25-microgram doses. They developed levels of antibodies just as strong as young adults who get full-strength shots, the company said.

Increase in hospital visits during Omicron surge

Moderna's study in tots was conducted during the Omicron surge and found the same trend: While there were no severe illnesses, the vaccine proved just under 44 per cent effective at preventing milder infections in babies up to age two, and nearly 38 per cent effective in the preschoolers.

But Hoge said high antibody levels still should translate into protection against severe disease in young kids just like they do in adults, "which ultimately is probably the strongest reason for somebody to get vaccinated."

Moderna said the small doses were safe, and the main side effects were mild fevers like those associated with other commonly used pediatric vaccines.

While COVID-19 generally isn't as dangerous to youngsters as to adults, some do become severely ill. The CDC says about 400 American children younger than five have died from COVID-19 since the pandemic's start, while Health Canada has documented 24 deaths attributable to the coronavirus of those under 11, more than has been seen in Canadians 12 to 19 years old (10 deaths overall).

Health officials in both Canada and the U.S. noted the fact that those under five were seen at hospitals at higher rates during the Omicron surge than for the original strain of the virus and other variants. Omicron's more exponential growth and the fact the variant has been seen to hinder the upper respiratory tract, where children can be more susceptible to illness than adults, has been noted.

Read the Moderna release on the vaccine study for under-6 group:

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Moderna's vaccine for 6 to 11 group just authorized in Canada

Canada and the U.S. diverge in terms of authorization of Moderna's COVID-19 vaccines.

The U.S. government made a heavy investment in the Massachusetts-based company, among others, as part of an order to get vaccines into arms as soon as possible as part of Operation Warp Speed after the pandemic erupted in 2020.

Some Canadian clinics, like here in Ottawa on Jan. 27, utilized costumed performers, stickers and balloons to make the vaccination process more comfortable for children aged five to 11. (Francis Ferland/Radio-Canada)

But so far, the company's vaccine for adults is the only one approved in the U.S. The FDA never ruled on Moderna's application for teen shots because of concern about a very rare side effect. Heart inflammation has occurred occasionally in teens and young adults, mostly males, after receiving either the Pfizer or Moderna vaccines. 

The heart risk also seems linked to puberty, and regulators in Canada, Europe and elsewhere recently expanded Moderna vaccinations to kids as young as six.

"That concern has not been seen in the younger children," said Northwestern's Muller.

Moderna's vaccine for those 12 to 17 was authorized for use in Canada in August of last year, while last week the go-ahead was given by Health Canada for its COVID-19 shots for kids aged six to 11, nearly four months after Pfizer's product for a similar age group (five to 11) was approved.

It's not clear what the uptake for a COVID-19 vaccine in those under five would look like in Canada.

Health Canada tracking indicates that 84 per cent of Canadians 12 to 17 have been fully vaccinated.

With respect to Canadians five to 11, nearly 57 per cent have received one dose, with 37 per cent fully vaccinated since shots were administered beginning in December. While the pace of vaccination in that age cohort has concerned some Canadian health officials, it is not out of step with what has been seen globally — Canada's rate of vaccination for that cohort outpaces most Western European countries, the U.S. and Israel.

With files from CBC News

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