Functional Impact of Acute Respiratory Viral Infections in Older Adults

The prevention of infectious diseases in older adults remains a major public health challenge, as acute respiratory infections are a leading cause of hospitalisation, mortality, and functional decline worldwide. Immunosenescence and environmental exposures increase susceptibility to infection and reduce vaccine effectiveness in this population. Respiratory viruses, including influenza, SARS-CoV-2, respiratory syncytial virus, and human metapneumovirus, account for a substantial share of this burden, much of which is vaccine-preventable. However, their impact on functional decline and recovery in older adults remains insufficiently characterized. This international study aims to assess the effect of hospitalization for major respiratory viral infections on loss of autonomy in individuals aged 60 years and older, to inform targeted prevention and vaccination strategies.

The prevention of infectious diseases in older adults represents a major public health challenge due to their substantial impact on morbidity, mortality, and loss of functional capacity. Acute respiratory infections are among the leading causes of hospitalization and death in this population worldwide. Ageing is associated with a progressive decline in immune function, resulting in increased susceptibility to infections and reduced vaccine effectiveness. In addition, environmental factors such as residence in collective living settings and repeated exposure to healthcare environments further increase the risk of exposure to and transmission of infectious agents. The pathogens most frequently involved include respiratory viruses namely influenza, SARS-CoV-2, respiratory syncytial virus, and human metapneumovirus as well as bacterial pathogens, particularly Streptococcus pneumoniae, and certain fungal agents. A substantial proportion of these infections are potentially preventable through vaccination. Despite advances generated by the European IMI VITAL project and the AEQUI case-control study, data remain limited regarding the functional consequences of acute respiratory infections in older adults, particularly their impact on dependency, frailty, and post-infectious recovery. This international study aims to address these knowledge gaps by evaluating the impact of hospitalizations related to influenza, SARS-CoV-2, respiratory syncytial virus, and human metapneumovirus on loss of autonomy in individuals aged 60 years and older. The findings are expected to strengthen the scientific evidence base needed to inform targeted vaccination and prevention strategies, ultimately contributing to healthier ageing.