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New medicines promising for fighting RSV in infants, say B.C. researchers

Recent study shows respiratory illness continues to target children under 6 months the most
A doll sits in a neonatal intensive care incubator during a tour showcasing the technology used in the William Osler Health Centre, on Oct. 11, 2007. A 2023 Canadian study shows infants under the age of six months make up almost 50 per cent of all RSV-related pediatric hospital admissions. THE CANADIAN PRESS/J.P. Moczulski

B.C. researchers say a new national study of pediatric RSV cases both before and during the COVID-19 pandemic shows the respiratory illness continues to impact young infants the most. This, the researchers say, is a strong argument for welcoming up-and-coming medicines.

Published last week, the study analysed the number of times a child under the age of 16 was in a pediatric hospital in Canada with respiratory syncytial virus (RSV), between 2017 and 2022. It did not track whether RSV was the patient’s primary reason for admission.

In total, the study found 11,014 total hospitalizations were recorded during that period, almost half of which (5,488 cases) were among children under six months of age. The young infants were also the most likely age group to be admitted to intensive care, making up 60.8 per cent or 1,576 of the cases that ended up there.

While most RSV infections go away on their own, Dr. Nirma Vadlamudi, the first co-author of the study and a vaccine researcher at the BC Children’s Hospital, said the prevalence of cases among infants can be cause for concern.

“The main issue is that children who are admitted to hospital with RSV in their early childhood have higher risk for developing asthma,” she said.

Although rare, RSV can also cause and contribute to death, added study senior co-author Dr. Julie Bettinger.

“It’s not without severe consequences. This is an infection that actually kills,” said the University of British Columbia pediatric infectious diseases professor.

She said they were relieved to find in their study that RSV doesn’t appear to have mutated or changed in severity since 2017, but said the virus remains a serious problem.

With confirmation that it continues to impact the youngest Canadians the most, the study’s authors say two new medicines designed to protect infants could play a big part in reducing the number of RSV cases.

The first is a vaccine administered during pregnancy that protects babies in the early months of their lives outside of the womb. Health Canada accepted Pfizer’s RSV vaccine submission last April and is expected to approve it.

The second option is a monoclonal antibody. This involves injecting man-made antibodies directly into someone, so they can immediately fight off a virus. A vaccine, by contrast, teaches a person’s immune system how to combat a virus on its own over the long term, including the production of natural antibodies.

While monoclonal antibodies to fight RSV have been around for some time, they have only been effective in the short term and typically reserved for infants with underlying health conditions. The study authors say a newly available long-acting monoclonal antibody, known as nirsevimab, promises to protect all infants for longer.

“I think anything we can do to reduce the severity of infection is worth it,” Dr. Bettinger said.

In the most recent Oct. 5 respiratory illness report from the B.C. Centre for Disease Control, the centre said RSV activity in the province remains low so far. It said cases are comparable now to pre-pandemic levels.

READ ALSO: Vaccine fatigue: 55% of British Columbians plan to get a COVID shot this fall

About the Author: Jane Skrypnek

I'm a provincial reporter for Black Press Media after starting as a community reporter in Greater Victoria.
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