Severe respiratory syncytial virus infection in older adults – burden, clinical outcomes and implications for care

Background

Respiratory syncytial virus (RSV) infection in adults remains under-researched. Increased testing is revealing an emerging picture of severe outcomes within the most prevalent lower respiratory tract infections. Understanding risk factors is increasingly important, especially in light of the recent approval of prophylactic vaccination.

Methods

Retrospective evaluation of all real-time polymerase chain reaction-positive RSV cases detected at our institution over three consecutive infection seasons from 2021 to 2024 in adults aged 60 years and older. Subsequent assessment of patients with severe infection requiring hospitalization.

Results

A total of 574 individuals were included, 57 % of whom were female, with a median age of 81,1 years (IQR 74–87 years). The peak number of cases occurred between September and March. We found a hospitalization rate of 51,2 % (representing an incidence of 1 case per 758 inhabitants per year in the elderly population of our region) and an in-hospital mortality rate of 15,6 % (19,1 % if transferred patients are excluded) among older adults with PCR-confirmed RSV infection. Heart failure (p ≤ 0.001), asthma (p = 0005), chronic kidney disease (p = 0006), chronic obstructive pulmonary disease (p = 0,02) and active smoking (p = 0.01) were risk factors for hospitalization. Older age (p = 0.003), residing in long-term care facility (p = 0.003), active cancer (p = 0,01), lower lymphocytes (p ≤ 0,001) and higher creatinine (p = 0,01) were significantly associated with mortality.

Conclusions

This is the first review of health outcomes related to RSV infection in the elderly from a Portuguese hospital. It identifies a high burden of hospitalization and in-hospital mortality in the elderly population. Our findings highlight the need for increased awareness of RSV infection in adults, particularly older adults, and underscore the importance of targeted interventions, such as vaccination programs, to reduce the burden of this disease in vulnerable populations in Portugal.