How Does the Burden of Respiratory Syncytial Virus Compare to Influenza in Spanish Adults?

Addressing the Underestimated Burden of RSV in Older Adults in Europe: Epidemiology, Surveillance Gaps, and Public Health Implications

BACKGROUND/OBJECTIVES

Respiratory Syncytial Virus (RSV) is a leading cause of Lower Respiratory Tract Infections (LRTIs), posing a serious threat to vulnerable populations. Although growing evidence highlights its significant impact on older adults, RSV surveillance and data collection remain largely focused on children, underestimating the burden in older and high-risk adults. This review aims to synthesize current evidence on the epidemiological and clinical impact of RSV in older adults in Europe, assess existing surveillance strategies, and identify gaps to guide targeted public health responses.

METHODS

A two-phase research strategy was adopted. First, a comprehensive review of studies published between 2015-2025 was conducted via PubMed, focusing on the RSV burden in high-risk and elderly populations in Europe. Second, a structured web screening was performed to assess the status of existing RSV surveillance systems, focusing on eight selected European countries.

RESULTS

The review reported RSV prevalence rates ranging from 1% to 64.7% among older adults, with a high prevalence of comorbidities that exacerbate disease severity. Hospitalization rates varied between 12.6-55.9%, while mortality ranged from 2.15% to 13%, reaching up to 36% in intensive care settings. Surveillance systems for adult RSV infections across Europe remain limited and fragmented, with only 37.5% (3/8) of analyzed countries having dedicated surveillance for adults.

CONCLUSIONS

RSV represents a substantial and underrecognized threat to older adults, with significant clinical and healthcare implications. Strengthening surveillance, standardizing data collection, and ensuring equitable access to newly available preventive measures are urgent priorities to reduce the disease burden, protect vulnerable populations, and support resilient health systems against future health challenges.

Unveiling the Spectrum of Respiratory Syncytial Virus Disease in Adults: From Community to Hospital

BACKGROUND

Respiratory syncytial virus can cause severe disease in the older adult population. Three vaccines for RSV are currently market approved but the risk of RSV-hospitalization in (older) adults from a community level remains elusive. We aimed to estimate the risk of RSV-hospitalization and characterize the patients that end up in hospital.

METHODS

We manually analyzed records of adults aged ≥ 20 with RSV-infection between 2022 and 2024 in three hospitals in the Netherlands. These hospitals implemented routine RSV-testing at emergency departments. Using population-based data in combination with the in-hospital data, we estimated the population risk of RSV-hospitalization. Hospital records were analyzed to characterize the role RSV played in their course of disease.

RESULTS

We analyzed 709 RSV cases of whom 503 (70.9%) were hospitalized. Five hundred twenty-six patients were ≥ 60, and 183 were < 60 years of age. The population RSV-hospitalization rate was 6-20 per 100.000 patients aged 20-59 years and 43-236 per 100.000 for those ≥ 60. The highest risks were observed in those with COPD (1702 per 100.000) and with congestive heart disease (2383 per 100.000). RSV caused clinically relevant infection in 88% of hospitalized cases but was only mentioned using specific ICD-codes in 4.4%. Comorbidity was prevalent (88.5%) and exacerbation of underlying disease caused of 46.3% of RSV-related hospital admissions. ICU admittance was 11.2% and in-hospital mortality was 8.1%.

CONCLUSION

The risk of RSV-hospitalization from the community is low but is increased substantially in those with underlying disease. RSV is often clinically relevant in hospitalized patients by causing exacerbation of underlying disease but is infrequently mentioned in specific ICD-codes.

Respiratory syncytial virus infections in adults

Respiratory syncytial virus (RSV) infections as an important cause of acute respiratory illness (ARI) and exacerbation of chronic lung disease in adults especially affect older adults, adults with immunosuppression, and adults with chronic disease, particularly pulmonary or cardiac disease, who may develop more severe complications. A more accurate determination of the burden of RSV infection in the adult population would improve the approach to infection, especially considering the growth of the older adult population in the world and, above all, that there are currently three approved vaccines aimed at the adult population that could have an effect on the prevention of RSV infection. This review article reviews the most relevant and novel scientific evidence on the epidemiology, diagnosis, treatment and prevention of RSV infection in the adult population.

Severity and outcomes of adult respiratory syncytial virus inpatient compared with influenza: observational study from Japan

BACKGROUND

Respiratory syncytial virus (RSV) significantly impacts not only children but also adults. However, knowledge of the severity and outcomes among adult RSV inpatients is still limited.

OBJECTIVES

To clarify the short- and long-term health threats associated with adult RSV infections.

METHODS

This retrospective observational study included 56,980 adult inpatients aged 18 years and older due to RSV or influenza infection between April 2010 and March 2022. After inverse probability weighting adjustment, we used Poisson's regression to estimate the risk of outcomes.

RESULTS

The RSV group had a higher risk of requiring mechanical ventilation during hospitalization compared to the influenza group (9.7% vs. 7.0%; risk ratio (RR), 1.35; 95% confidence interval (CI), 1.08-1.67). In-hospital mortality was comparable between RSV and influenza groups (7.5% vs. 6.6%; RR, 1.05; 95% CI, 0.82-1.34). RSV group was associated with increased risk of readmission within 1 year after surviving discharge (34.0% vs. 28.9%; RR, 1.19; 95% CI, 1.07-1.32) and all-cause mortality within 1 year of admission (12.9% vs. 10.3%; RR, 1.17; 95% CI, 1.02-1.36). In the age-stratified analysis, the RSV group aged 60 years and older had a higher risk than the influenza group for in-hospital death, readmission and all-cause mortality within one year.

CONCLUSIONS

RSV infections demonstrated comparable or greater health threats than influenza infections not only during hospitalization but also in long-term outcomes. The findings underscore the threat of RSV in adults, the impact on healthcare systems and the need for continued development of public health counter measures against RSV.

Hospitalisation due to respiratory syncytial virus in a population-based cohort of older adults in Spain, 2016/17 to 2019/20

Background

Respiratory syncytial virus (RSV) is a major cause of acute respiratory infection that can lead to complications in risk groups.

Aim

We aimed to estimate the incidence of RSV hospitalisation in adults, determine the risk factors and characterise priority groups for prevention.

Methods

This population-based cohort study included adults 60 years and older in Navarre, Spain, in seasons 2016/17 to 2019/20. We estimated the rate of RSV hospitalisation confirmed by PCR and evaluated risk factors using Poisson regression.

Results

Within 642,622 person-years analysed, we detected 544 RSV hospitalisations (average annual rate: 84.7/100,000). The rate varied among seasons between 59.7 and 95.6 per 100,000. The rate ratio of hospitalisation was higher than 3 from the age of 75 years and around 7 in the 85–94 years age group compared with those aged 60–64 years. Nursing home residence, functional dependence, haematological cancer, chronic obstructive pulmonary disease (COPD), asthma, cardiovascular disease, severe obesity, diabetes and chronic kidney disease were independent risk conditions. Rate of RSV hospitalisation was higher than 300 per 100,000 among people with haematological cancer or nursing home residence, those aged ≥ 75 years with COPD or functional dependence, and those aged ≥ 85 years with asthma or cardiovascular disease. These groups represented 13.2% of all adults aged ≥ 60 years and 50.7% of their RSV hospitalisations. On average, these groups had one RSV hospitalisation per 307 person-years.

Conclusion

Advanced age, in addition to nursing home residence, functional dependence and some comorbidities define priority groups for RSV vaccination.

Adult vaccinations against respiratory infections

INTRODUCTION

Lower respiratory infections have a huge impact on global health, especially in older individuals, immunocompromised people, and those with chronic comorbidities. The COVID-19 pandemic highlights the importance of vaccination. However, there are lower rates of vaccination in the adult population that are commonly due to a missed opportunity to vaccinate. Vaccination offers the best strategy to prevent hospitalization, complications, and death caused by lower respiratory infections.

AREAS COVERED

In this review, the authors provide an overview of the vaccines for lower respiratory infections in the adult population. The review highlights the available data about the impact of vaccines on preventing respiratory infections, focusing on the pneumococcal vaccine, influenza vaccine, COVID-19 vaccines, and respiratory syncytial virus (RSV) vaccines. The authors discuss the currently available scientific evidence on the role of vaccines against respiratory infections. Finally, the authors review the current recommendations for vaccines in the adult population.

EXPERT OPINION

Scientific evidence on the effectiveness of vaccines against respiratory infections is important. An efficient implementation of adult immunization strategies will provide an opportunity to decrease the global burden of lower respiratory infections. Recognizing the existing vaccines and their recommendations for the adult population is essential to achieve a high vaccination rate in the population.