Dr. Noah Ivers remembers thinking his infant son just had a cold.
But then, he was “clearly struggling to breathe” and had to be rushed to the hospital.
His son had respiratory syncytial virus, or RSV — a common illness with often mild symptoms in children and adults. But for infants and seniors, RSV is a major cause of serious lower respiratory tract infections that can land them in hospital.
Despite his medical knowledge, Ivers said seeing his baby with an oxygen mask left him feeling “unempowered.”
“The most you could do in that moment was hug them and hope,” said Ivers, who is both a primary care physician and a scientist at Women’s College Hospital in Toronto.
That happened about nine years ago, he said, noting there’s no antiviral treatment for RSV — so shielding infants from serious illness in the first place is key.
But until this year, babies across Canada were only given an antibody drug that protects against severe RSV if they were born prematurely or had other significant risk factors. For years, that antibody was palivizumab, which had to be given every month throughout the RSV season to maintain immunity.
This fall and winter, Ontario, Quebec and Nunavut will offer the newer monoclonal antibody nirsevimab — approved by Health Canada in the spring of 2023 — to all babies going through their first RSV season.
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Unlike palivizumab, only one dose of nirsevimab is needed to provide protection throughout the fall and winter, when RSV is most widely circulating.
Although they are administered by injection, nirsevimab and palivizumab are not vaccines, which provoke the body’s immune system to develop antibodies and other defences against a certain virus or bacteria.
Instead, they are already formed antibodies that give passive immunity against serious illness from RSV.
Last May, the National Advisory Committee on Immunization changed its guidelines to recommend “building towards a universal RSV immunization program for all infants” in Canada using nirsevimab, given the “significant burden of disease in all infants from RSV and the impacts of RSV on the Canadian health system.”
Ontario, Quebec and Nunavut are the first provinces and territory to adopt that recommendation and offer nirsevimab to all infants free of charge — a move Ivers welcomes “as a family doc and also as a parent who’s been through this.”
“If there’s something you could do to prevent your kid becoming short of breath and watching them with their ribs heaving in and out and you’re watching them needing to get an oxygen mask — if there’s something simple in your power to do that, please, you know, take advantage of it,” he said.
The other provinces and territories have not announced a universal RSV antibody program for this year. According to their websites, many of them are continuing to offer palivizumab, and only to premature and other high-risk infants.
In an email to The Canadian Press, the Saskatchewan ministry of health said it is “currently assessing” how to best use nirsevimab going forward.
In Ontario, “all infants up to 12 months old, and children up to 24 months who are at high risk of severe illness from RSV are eligible for immunization,” the provincial ministry of health website says.
Ivers said starting this month, hospitals in Ontario will offer nirsevimab to newborn babies. Doctors can also give infants the injection along with their routine vaccinations at the two and four-month marks, he said.
In Quebec, all infants born on or after April 2 of this year will be eligible for nirsevimab, according to the provincial website. It’s not clear exactly when the injections will become available in that province.
Older babies with conditions that put them at higher risk of severe illness from RSV — including cystic fibrosis, lung and heart conditions — may also get nirsevimab during their second RSV season in Quebec.
Nunavut will also provide the antibody injection to newborns and infants during their first RSV season, as well as children up to 24 months old who continue to be at risk of severe illness. The territory has not yet confirmed specifically when it will be available.
Although infants born prematurely are at higher risk of getting very sick with RSV, it’s full-term infants who have made up the majority of hospitalizations each season, Ivers said.
“They were healthy and unlucky,” he said.
Ivers, who declared no affiliation or financial connection to the manufacturers of the monoclonal antibodies, said the preventive RSV treatment will also help the health-care system overall this respiratory virus season.
“If we have thousands less babies in the hospital, there’s room suddenly in our system to do so much more,” he said.
“There’s knock-on effects that is beyond just the individual babies and their families that we’re protecting.”
