Age Range Most Susceptible to RSV Infection
Infants in the second month of life have the highest RSV hospitalization rate, nearly twice that of any other age group, with the first year of life accounting for approximately 75% of all pediatric RSV hospitalizations. 1
Highest Risk Age Groups
Infants Under 6 Months
- Infants aged 2 months have the single highest RSV hospitalization rate of any age group 1
- The second highest risk group is infants in their first month of life 1
- Children younger than 2 years represent the primary target for RSV prevention strategies, with approximately 60% of outpatient RSV cases occurring in children aged 2-5 years and 40% in children from birth to 2 years 1
- Among hospitalized children, 53.5% were under 6 months of age, demonstrating this group's disproportionate disease burden 2
Infants 6-24 Months
- This age group accounts for 31.7% of RSV hospitalizations 2
- Young chronologic age remains the most significant risk factor for RSV hospitalization, independent of other factors 1
- Less than 20% of all pediatric RSV hospitalizations occur during the second year of life 3
Children Over 24 Months
- Children aged 24-59 months represent 14.8% of RSV hospitalizations 2
- The mean age of hospitalized children with Down syndrome was notably older (1.3 years; range 0-6.1 years) compared to children without Down syndrome, with some cases extending through 17 years of age 1
- Comorbidities become increasingly important with age: 25% of children under 6 months had comorbidities versus 70% of children aged 24-59 months 2
Older Adults: The Second Peak
Adults 60 Years and Older
- Adults aged 75-84 years have RSV hospitalization rates of 210 per 100,000, while those ≥85 years have rates of 343 per 100,000 1
- Approximately 76.3% of all adult RSV-associated hospital admissions occur in people aged 75 years and older 1
- Annual RSV hospitalization incidence increases dramatically with age: 7.7-11.9 per 100,000 for ages 18-49 years, 33.5-57.5 per 100,000 for ages 50-64 years, and 136.9-255.6 per 100,000 for those ≥65 years 1
Mortality and Severity in Older Adults
- Patients aged ≥75 years have 3.64 times greater risk of serious outcomes (hospitalization, emergency department visit, or pneumonia) compared to those aged 60-64 years 1
- In-hospital mortality rates are 4.6% for ages 60-74 years and 6.1% for ages ≥75 years 1
- Advanced age (>75 years) is associated with longer hospitalization duration and poorer 30-day and 60-day survival 1
Clinical Implications by Age
For prevention strategies, palivizumab prophylaxis targets infants born ≤35 weeks gestational age who are 6 months or younger at RSV season onset, and children with specific high-risk conditions who are 24 months or younger 4
For vaccination strategies, all adults ≥60 years should receive RSV vaccine, with universal vaccination recommended for those ≥75 years regardless of comorbidities 5
The bimodal distribution of severe RSV disease—with peaks in early infancy and advanced age—reflects both immunologic immaturity in the very young and immunosenescence in older adults 1, 6