Universal RSV immunization: Policy must be fit for purpose
Disease prevention has never been more critical. Seasonal respiratory diseases are known stressors that stretch human and financial resources to their limits. In Canada, the financial burden of respiratory diseases is staggering. A recent study by Nirma Khatri Vadlamudi and others in the Lancet indicates that RSV hospitalizations cost the Canadian healthcare system an average of $66 million annually, with infants under six months accounting for nearly half of those costs.
The reality of RSV in Canada
Respiratory syncytial virus (RSV) is endemic to Canada, joining influenza and COVID-19 as a significant annual threat. Most children are infected with RSV before age two. The burden of RSV on the healthcare system is substantial as children often require hospitalization and intensive care support as complications such as acute bronchiolitis and lower respiratory infections can occur. According to Dr. Elissa Abrams and others, 5% of cases require intensive care. Similarly to most other respiratory viruses with various genetic types, reinfection with RSV is a possibility.
Among infants at high risk of RSV, research has found the following groups and chronic medical conditions to impact health outcomes in substantial numbers:
- Research by Xin Wang and others in the Lancet identified preterm infants facing disproportionately high burden of RSV-associated disease, accounting for 25% of hospitalizations.
- Dr. Marina Viñeta Paramo and others in JAMA Network undertook a retrospective study in British Columbia that discovered preterm infants (less than 28 weeks gestational age) and infants with chronic medical conditions, particularly infants with Down syndrome, multisystem health conditions or cardiovascular disease to be at high risk of RSV infection throughout their first two years of life.
- Indigenous infants and those born in remote and rural communities also experience a high burden of disease.
However, that study by Dr. Abrams and others found that severe outcomes are also associated with healthy, full-term infants, where the burden was found to be higher than influenza. A critical finding by Vadlamudi and others using recent Canadian surveillance is that over 80% of children hospitalized with RSV had no known risk factors.
New tools, proven success
We are approaching the time of year when policymakers are reexamining their budgets and determining which healthcare needs will be prioritized in the next fiscal year. Despite respiratory diseases like RSV making their mark in hospital waiting rooms and in acute care settings across the country, their prevention seldom receives the attention required to reduce their impact the following season.
The approval of nirsevimab (a long-acting monoclonal antibody) and new RSV vaccines for older adults and pregnant women has changed the RSV prevention landscape. Real-world evidence has been definitive showing all products to reduce medically attended RSV infection and associated acute respiratory illness (ARI).
Research in the Lancet by Dewan Sumsuzzman and others., has shown nirsevimab reducing lower respiratory tract infections and hospitalizations, as well as emergency visits in infants under two years of age. Infant protection during Quebec’s first universal nirsevimab immunization campaign was reported by Dr. Sara Carazo and others to have reduced RSV-associated hospitalization by 66% and effectiveness against emergency admission and intensive care admission were measured to be as high as 86% and 88%, respectively.
Administrative data from Ontario’s 2024–2025 rollout shows that 73% of births received RSV protection, including the option of maternal vaccination in shielding newborns through passive immunity. Real-world findings by Thomas Williams and others. showed that maternal vaccination reduces the risk of early-infancy hospitalization. In older adults, Sara Tartof and others discovered RSV vaccination as effective at preventing hospitalization and complications as well.
The implementation gap
Despite this success, the shift towards universal RSV immunization programs has been fragmented by numerous challenges. According to Bosco Paes and others in Human Vaccines and Immunotherapeutics, experiences from Quebec and Ontario reveal policy and program implementation barriers that must be addressed.
Other countries have overcome these barriers by implementing strategies that improve RSV uptake such as screening infants for RSV eligibility in hospital settings to identify maternal immunization status; prioritizing follow-up in community healthcare settings for infants missed during hospital discharge or born outside the RSV season and comprehensive caregiver and health professional education.
Inefficient hospital screening leads to product waste and missed immunizations during the critical birth window. Variances in program start dates, product options and reduced community access mean that an infant's protection often depends on their postal code or birth month, creating public confusion. National RSV surveillance in Canada is still in its infancy, making it difficult for policymakers. More detailed and granular data is required to track real-time shifts in viral timing and virulence.
Quality healthcare services require a call for policy cohesion
To achieve a truly universal RSV immunization strategy, provincial and territorial policymakers must adopt a policy that includes ensuring protection is offered to everyone at risk of disease. Supporting community healthcare providers such as doctors to reach expecting mothers and infants born outside the RSV season is critical.
Also of importance is the need to enhance surveillance to ensure the Canadian healthcare system can identify maternal immunization status, pivot as new data on product durability and viral shifts emerge.
For policy to be fit for purpose, it must ensure that every Canadian regardless of where they live or when they were born has equitable access to RSV prevention.
Lucie Marisa Bucci is an MA with Bucci-Hepworth Health Services Inc. Dr. Vivien Brown is a family doctor in Toronto. Craig Thompson is an RN with Bucci-Hepworth Health Services Inc.
Conflicts of interest: For Dr. Brown: ABCella, Astellas, Bayer, Biosyent, Eisai, Eli Lilly, GSK, Idorsia, Moderna, Merck, NovoNordisk, Pfizer, Sanofi, Sequeris, Sandoz. For Bucci and Thompson: Merck Canada, Pfizer Canada, Astrazeneca, Sanofi Pasteur, World Health Organization, University of Toronto, Public Health Association of BC and The JAMIE Group.