ASTHMA, the most common chronic illness in children and adolescents, affects over 300 million people worldwide and causes significant disability, particularly in low- and middle-income countries. A key contributor to asthma development is respiratory syncytial virus (RSV), a common cause of bronchiolitis in infants. Virtually all children are infected with RSV by the age of two, with the virus most often affecting infants between 3–6 months old. Research indicates that infants who suffer from RSV-related lower respiratory tract infections (RSV-LRTIs) are at significantly increased risk, by two- to twelve-fold, of developing asthma during childhood.
The link between RSV and asthma remains complex. Although strong epidemiological associations exist, a definitive causal relationship has not yet been established. Central to this uncertainty is whether RSV directly drives asthma or simply acts as a marker of underlying genetic and environmental susceptibility. Mechanistically, both RSV and asthma are associated with a Th2-skewed immune response, airway inflammation, and remodelling, but the specific pathways remain incompletely understood.
This research highlights the importance of identifying high-risk children through biomarkers and better understanding neutrophil function in RSV infection. The dual role of neutrophils, essential for viral clearance yet potentially contributing to immunopathology, adds to the complexity of asthma development.
Importantly, current RSV prevention strategies, such as immunoprophylaxis and maternal vaccination, may influence asthma risk. However, trial results remain inconsistent, and long-term outcomes are not fully understood. There is a growing need for large, longitudinal studies using modern statistical and molecular tools to clarify the relationship between RSV and asthma.
In conclusion, while causality remains uncertain, the evidence linking severe RSV infection to long-term respiratory morbidity is strong enough to justify prioritising RSV prevention. With further research, clinicians may soon be able to develop targeted, personalised strategies to reduce asthma incidence, particularly in vulnerable populations. This would not only improve individual outcomes but also reduce the broader societal burden of paediatric asthma.
Reference
Ma R et al. The impact of respiratory syncytial virus on asthma development and exacerbation. Ann Allergy Asthma Immunol. 2025;DOI:10.1016/j.anai.2025.05.011.
