Age and Comorbidities Drive RSV Hospitalization Rates in Older Adults

Respiratory syncytial virus (RSV) hospitalization rates among older adults residing in Spain rise significancy with age, particularly among those with comorbidities and those who are nursing home residents, according to study findings published by investigators in Eurosurveillance. These data highlight the substantial variation in hospitalization risk based on age and health status, underscoring the need for targeted interventions.^1,2

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RSV is marked as one of the leading causes of acute respiratory tract infection, resulting in severe complications among adults aged 60 years and older and adults with major chronic comorbidities.¹ Recent reviews estimate approximately 787,000 annual RSV-related hospitalizations among older adults in high-income countries, with a 6% to 8% in-hospital fatality rate, rising to 10% in high-risk individuals. However, precise hospitalization rates have been difficult to establish due to limited pre-pandemic screening and increased post-pandemic viral circulation variability.¹

In the current study, researchers aimed to evaluate the average incidence rate of hospital admissions linked to RSV in adults aged 60 years and older across 4 RSV seasons to determine risk factors and population groups in need of prevention.²

The population-based cohort study obtained electronic medical records in the region of Navarre, Spain, including 4 cohorts starting on October 1 of each RSV season from 2016/2017 to 2019/2020. Individuals included in the cohorts were aged 60 years or older, with RSV hospitalizations confirmed with PCR testing.¹

The study authors noted that RSV hospitalization incidence rates were calculated by dividing total cases by population sums across 4 study periods, stratifying rates by sex and age. Poisson regression models were used to assess risk factors, with multivariate analyses adjusted for various demographic and health variables.¹

Across the 4 RSV seasons studied, individuals aged 60 years and older accounted for 84.7 hospitalizations per 100,000 among individuals older than 60 years. However, the study authors noted that the incidence rate varied based on age and risk factors.^1,2

The results demonstrated that RSV hospitalization rates showed no significant difference between males and females (92.2 vs. 78.4/100,000, P = 0.058), but varied significantly by age (p<0.001), with those 75 and older, representing 38.6% of the population, accounting for 76.1% (n = 414) of hospitalizations. Compared with individuals aged 60 to 64 years, the incidence rate increased 2-, 3-, 4-, and 6-fold among individuals older than 70, 75, 80, and 85 years, respectively. Additionally, rates peaked at 243.9/100,000 for individuals aged 85 to 89 and 268.7/100,000 for individuals aged 90 to 94 years.^1,2

Individuals with risk conditions had significantly higher rates (131.1 vs. 18.8/100,000, p<0.001), with hematological malignancies (399.0/100,000), nursing home residence (366.7/100,000), functional dependence (348.1/100,000), and chronic obstructive pulmonary disease (COPD) (269.7/100,000) showing the highest rates.^1,2

Further conditions connected with higher rates of RSV include asthma, cardiovascular disease, chronic kidney disease, and dementia exceeding 200/100,000.^1,2

Additionally, the study had several limitations, including potential variations in RSV circulation across regions and seasons; potential misclassification or pre-existing chronic diseases from electronic records; and the need for further research on other RSV outcomes, vaccine effectiveness, and economic impact.¹

The findings suggest that prioritizing preventive measures for individuals 60 and older with hematological cancer or nursing home residence, those over 74 with COPD or functional dependence, and those over 84 with asthma or cardiovascular disease would effectively address half of RSV hospitalizations in this age group while immunizing only 13% of older adults. The study authors noted that this approach could significantly reduce the strain on hospital resources during peak RSV season and prevent RSV-related deaths.^1,2

REFERENCES

1. Hospitalization due to respiratory syncytial virus in a population-based cohort of older adults in Spain, 2016/17 to 2019/20. Eurosurveillance. News release. March 13, 2025. Accessed March 19, 2025. https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2025.30.10.2400364

2. RSV hospitalization risk among older adults linked to age and certain risk conditions. EurekAlert!. News release. March 13, 2025. Accessed March 19, 2025. https://www.eurekalert.org/news-releases/1076784