RSV Risk Factors Across Age Groups: From Infants to Older Adults

Dr. Simões introduces an important clinical concept for older adults: rather than focusing on any single risk factor, it is the accumulation of conditions that matters most. Diabetes alone, for example, may not significantly increase hospitalization risk, but when combined with renal disease and cardiac disease, risk becomes exponential. He identifies COPD and cardiac and pulmonary comorbidities as the most clinically relevant risk factors in older adults.

On global seasonality, Dr. Simões notes that RSV circulation follows a winter pattern in temperate climates but shifts to the rainy season in tropical regions — a pattern he and colleagues first described in India four decades ago. In equatorial settings and island regions, RSV can circulate year-round. This variation has direct implications for the timing of maternal immunization programs: regions with extended or year-round RSV circulation must grapple with whether to vaccinate seasonally or throughout the year. The panel emphasizes that a maternal history of asthma is an underappreciated but important risk factor for RSV-related hospitalization in infants.

In the next episode, "RSV Clinical Presentation: Recognizing Severe Disease and Hospitalization Risk," Drs. Tan and Creech reviews the spectrum of RSV symptoms in children and the high hospitalization burden, particularly in infants under 12 months of age.