Respiratory syncytial virus (RSV) is often perceived as a paediatric illness, but its impact on older adults is increasingly recognised as a significant public health concern (1,2). While RSV infection in healthy adults typically presents with mild, cold-like symptoms, older adults, particularly those with underlying comorbidities, are at increased risk for severe disease, hospitalisation, and even death (1,2).
RSV is largely undetected and substantially underestimated in adults (3).
Before the Covid-19 pandemic in 2019, RSV infection followed a predictable seasonal pattern, typically spreading throughout the winter months (3).
During the pandemic the incidence dramatically decreased due to social distancing and other hygiene practices but this was followed by a notable rebound of all viral infections (3). While precise incidence rates in older adults are challenging to determine due to low awareness, suboptimal diagnostic sensitivity, and lack of robust RSV surveillance systems (4) studies suggest that RSV is responsible for a substantial burden of respiratory illness in this age group (1-5).
Annual attack rates in the USA range from 2% to 10% in community-dwelling older adults, but this can increase to as high as 80% in outbreaks in long-term care facilities (5).
Older adults at increased risk of severe infection
Several factors predispose older adults to severe RSV infection (1). Immunosenescence, the age-related decline in immune function, plays a crucial role (6).
Comorbidities such as chronic obstructive pulmonary disease (COPD), congestive heart failure, obesity, diabetes mellitus, and chronic kidney disease further increase the risk of severe outcomes (1). Nursing and care home residents are at increased risk due to increased prevalence of comorbidities, increased frailty and increased risk of spread in a closed environment (7).
RSV infection in older adults can lead to a range of serious complications (2,3). Lower respiratory tract infections, including bronchiolitis and pneumonia, are common and can result in hospitalisation, intensive care unit admission, and mechanical ventilation (2,3)
Exacerbations of pre-existing conditions like COPD and heart failure are also frequently observed (2,5). RSV infections in older adults are also associated with a significantly higher risk of death compared to influenza infection (8).
RSV diagnosis in older adults is challenging
RSV infection in older adults can mimic other respiratory illnesses, making clinical diagnosis challenging (2,3,5). Symptoms often overlap with those of influenza and other common respiratory viruses, including cough, rhinorrhoea, sore throat, headache, and fever (2,3,5).
Older adults may also present with atypical symptoms such as worsening of underlying cardiopulmonary diseases (e.g, COPD), confusion, dizziness, and falls (9).
A definitive diagnosis of an RSV infection therefore requires laboratory confirmation, which can be achieved through viral culture, antigen detection and RNA detection by reverse transcriptase polymerase chain reaction (RT-PCR) assays (3,5). In contrast to the insensitivity of culture and antigen assays and the poor clinical utility of serological tests (IgG/IgM), PCR assays have become the gold standard in respiratory virus detection offering both high sensitivity and specificity (3,5).
Even so, adults are still less likely to test positive to RSV due to low viral loads, especially if only upper respiratory tract samples are tested (10).
Effective preventative strategies in older adults are essential.
RSV infection is an important cause of morbidity and mortality in older adults (1,2). Clinicians should maintain a high index of suspicion for RSV in older adults presenting with respiratory symptoms, particularly during the RSV season (11).
Prompt diagnosis and appropriate management are crucial to minimise complications and improve patient outcomes (12).
Given the substantial clinical and economic burden of RSV, the development of effective preventive strategies is paramount (13,14). Recently, significant advancements have been made in RSV vaccine development, which represents a major step forward in protecting this vulnerable population from the serious consequences of RSV infection (13). Ongoing research and surveillance efforts are essential to further refine our understanding of RSV epidemiology, optimise diagnostic strategies, and evaluate the long-term effectiveness of vaccination programmes in this population (11,12,15)
References:
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