Health Canada has authorized the use of an updated Moderna vaccine for COVID-19 for all Canadians over the age of six months. Empty Moderna vaccine vials are shown before a COVID-19 vaccine drive-thru clinic at Richardson stadium in Kingston, Ont., on Friday, July 2, 2021.

Image Credit: THE CANADIAN PRESS/Lars Hagberg

OTTAWA - Canada's senior public health officials are urging Canadians to get an updated COVID-19 vaccine this fall following the authorization of the first shot targeting the latest variants Tuesday.

Health Canada's regulatory branch approved Moderna's new Spikevax shot, which is formulated for the XBB.1.5 lineage of the Omicron variant.

Moderna said in a statement the first doses would be shipped to arrive in Canada on Wednesday.

"There is strong evidence showing that the benefits of this vaccine outweigh the potential risks," chief medical adviser Dr. Supriya Sharma said at a news conference in Ottawa.

Moderna began submitting data on clinical trials for the new vaccine at the end of June, and the decision follows an in-depth assessment of that data, Sharma said.

It's recommended that all adults and children as young as five get one dose of the new vaccine, if it has been at least six months since their last dose.

Children between six months and four years of age should get one dose if they have been vaccinated for COVID-19 before, but two doses if they haven't.

The decision comes as a small uptick in COVID-19 is appearing in Canada following months of what chief public health officer Dr. Theresa Tam said were historically low levels of the virus.

While Tam said overall, that uptick has been inconsistent and sporadically located, it is time for people to top up their resistance to the virus.

"I think one of the reasons that we think there's an increased uptick right now is this reduced immunity over time," she said.

Nationally, she said there have been signs of increased positive cases and hospitalizations due to COVID-19. Levels of COVID-19 have increased slightly in 10 of 40 cities where wastewater is being monitored by Health Canada.

The new vaccine targets the XBB.1.5 strain and its sublineages. That line of the virus accounts for 99 per cent of all positive tests in Canada currently.

Tam and Sharma said the Moderna vaccine shows a good immune response to all of them.

Health Canada is also reviewing submissions for XBB.1.5 vaccines from Pfizer-BioNTech and Novavax. Sharma said decisions on both will be forthcoming.

This report by The Canadian Press was first published Sept. 12, 2023.

News from © The Canadian Press, 2023