Children with chronic medical conditions face a significantly higher risk of hospitalization due to respiratory syncytial virus (RSV) in their first two respiratory virus seasons, according to a recent study by researchers at the UBC Faculty of Medicine, BC Children’s Hospital Research Institute (BCCHR) and BC Centre for Disease Control (BCCDC).
RSV is the leading cause of lower respiratory tract infections in infants and young children, with approximately one per cent of all children requiring hospitalization due to the virus within their first year of life.
For the past three decades, the only preventative medicine available in Canada has been an antibody administered monthly throughout the RSV season. In 2023, new products were approved for the use of RSV prevention in children, including RSVpreF, a vaccine administered during pregnancy, and nirsevimab, a single-dose long-acting monoclonal antibody.
As guidelines for these products are being set and refined, the new study in JAMA Network Open adds important evidence to inform which children would benefit most from preventative treatments.
Dr. Pascal Lavoie
“RSV is one of the most serious diseases for vulnerable young babies,” says senior author Dr. Pascal Lavoie, professor of pediatrics at the UBC Faculty of Medicine and investigator at BCCHR. “B.C. publicly funds RSV antibody immunizations for children younger than two years of age at moderate- and high-risk of severe RSV infection. This study helps us determine which children would benefit the most from these preventative interventions based on their risk profile and the effectiveness of the intervention.”
For the study, the research team looked at more than 430,000 children born in B.C. between 2013 and 2023. Of all children born in that decade, 1.1 per cent were hospitalized due to RSV at least once during their first two viral seasons.
When comparing the rates of hospitalizations, children with chronic medical conditions were hospitalized for RSV at twice the rate of children without underlying conditions. For some of these children, this increased risk persisted through their first two respiratory virus seasons.
The risk was particularly elevated among children with chronic conditions affecting the lungs, heart and digestive system, a premature birth under 28 weeks gestation and those with Down syndrome. Children with chronic medical conditions also required longer stays in hospital and pediatric intensive care units and more mechanical ventilation compared to children with no underlying health conditions.
“RSV prevention options have evolved significantly in the past two years,” says Dr. Lavoie. “We now have two more tools: a vaccine that can be given during pregnancy to boost the infant’s protection at birth, and a long-acting antibody that can be given directly to the baby. Most infants won’t need both, but it’s important to identify which children will benefit most from each approach.”
Canada’s National Advisory Committee on Immunization (NACI) recommends that provinces work toward universal RSV immunization for all infants, depending on what’s available and how much it costs. They also emphasize prioritizing infants at higher risk of severe RSV illness during their first or second RSV season.
“Our findings help identify which children may need antibody protection during their first and second RSV seasons, even if their mother received the RSV vaccine during pregnancy,” says Dr. Lavoie. “In keeping with the recommendations from NACI, these updated risk assessments are already helping to ensure that children in B.C. will be best protected for the next viral respiratory season.”
A version of this story was originally published on the BCCHR website.