Here’s what to know about new RSV antibody drug in Canada

Health Canada has approved a new antibody drug to help protect babies from the serious illness caused by respiratory syncytial virus (RSV).

Nirsevimab, also known under the brand name Beyfortus, was approved on April 19. Developed by AstraZeneca and Sanofi.

Nirsevimab is “a monoclonal antibody for the prevention of severe lower respiratory tract disease due to respiratory syncytial virus (RSV) infection in neonates and infants, which occurs during the first season of RSV,” a Health Canada spokesperson said. A representative, Mark Johnson, said in an email to The Canadian Press on Friday.

Administered by injection, the drug is also approved for children up to two years old if there is a risk of serious infection.

Monoclonal antibodies are made in laboratories to mimic natural antibodies to prevent or treat disease.

According to the European Medicines Agency, nilsevimab binds to a protein on the surface of the virus, interfering with its ability to enter the cells of the body, especially those in the lungs.

Canada already offers the monoclonal antibody palivizumab, also known as the Synagis brand name, to premature babies. The National Advisory Committee on Immunization (NACI) does not recommend palivizumab in healthy babies.

To maintain the efficacy of palivizumab, approximately one (up to four) injections per month are required during the RSV season. Nirsevimab requires only one dose for the entire RSV season.

“This is a game changer,” said Dr. Anna Banerj, a pediatric infectious disease specialist at the University of Toronto’s Dalarna School of Public Health.

Inuit babies in Nunavut are particularly vulnerable to RSV, Banerji said.

Many people become seriously ill each year and have to be transported from remote communities to hospitals in the south, she said.

A single dose of the drug can prevent many of these cases, Banerjee said.

Health Canada has approved nirsevimab for all infants, but it is not known if it will be widely administered.

It is up to provinces and territories to decide who gets the injections, often based on recommendations from the Canadian Agency for Health and Medical Technology (CADTH).

Health Canada said it expects nirsevimab to “be available for limited use during the fall/winter 2023/2024 respiratory season” while CADTH recommendations are pending. I was.

On Friday, the CADTH website said a review of “the cost-effectiveness of nirsevimab for preventing respiratory syncytial virus outcomes in infants” was “ongoing.”

Banerji said it was important to offer nirsevimab to all Inuit infants in Nunavut, not just premature infants, as is currently being done with palivizumab.

Preventing medevacs could offset the economic costs of providing nirsevimab to more infants, she said.

According to Public Health Canada’s website, most children in Canada have been infected with RSV by the age of two. Although it usually causes mild illness, it can be severe and is a common cause of bronchiolitis and pneumonia.

RSV, along with influenza and COVID-19, surged in pediatric hospital admissions last fall and winter. Infectious disease experts say this was in part due to the lifting of pandemic restrictions that had previously prevented respiratory infections, so children were exposed to RSV for the first time.


This report by The Canadian Press was first published on April 22, 2023.

The Canadian Press’ health coverage is supported through a partnership with the Canadian Medical Association.

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