Risk Factors for Respiratory Syncytial Virus Illness Among Patients with Chronic Obstructive Pulmonary Disease

Costs and Complications of Respiratory Syncytial Virus and Acute Respiratory Infections in the Adult Population: Analysis of a German Claims Database

BACKGROUND

Respiratory syncytial virus (RSV) infections pose health and economic burdens to adults. Using claims data, we estimated RSV-associated costs, healthcare resource utilization (HCRU), and complication rates from patients of a nationwide German health insurance database.

METHODS

We analyzed confirmed RSV, RSV-possible, and acute respiratory infection (ARI) cohorts, plus 1:1 matched control cohorts of individuals ≥ 18 years from 2010 to 2019. Matching was performed separately for patients 18-49, 50-59, and ≥ 60 years. Medical costs, HCRU, and sick leave were assessed for inpatients and outpatients. Complications were compared between cases and controls, and logistic regression assessed odds ratios (ORs) for risk.

RESULTS

Altogether, 2668 confirmed RSV index episodes occurred. In ≥ 60-year-olds, 862 episodes incurred mean excess costs of €3773 (95% confidence interval [CI]: €2956-€4591) per episode during the index quarter and €3286 (95% CI: €1841-€4732) in the following four quarters. Mean costs were €5553 per episode for inpatients and €116 for outpatients. In ≥ 60-year-olds, risk for congestive heart failure hospitalization (OR 2.3; 95% CI: 1.4-3.8), exacerbation of asthma (OR 6.0; 95% CI: 1.7-20.9), and chronic obstructive pulmonary disease (OR 3.9; 95% CI: 2.6-5.8) were higher for confirmed RSV than controls. In younger groups, costs, HCRU, and complications were also higher in cases than controls. The complication frequencies increased with age. RSV-possible episodes incurred mean excess costs of €615 (95% CI: €605-€626) during the index quarter and €610 (95% CI: €583-€637) during the following four quarters, while in the ARI cohort, the excess costs were €1003 (95% CI: €991-€1015) during the index quarter and €1003 (95% CI: €973-€1032) in the following four quarters. For all three cohorts, individuals who had comorbidities, were immunocompromised, or living in long-term care facilities incurred higher costs.

CONCLUSIONS

Confirmed RSV is associated with high excess costs - especially in hospital settings - and HCRU. Complication risk increased with RSV presence.

Patients With Inflammatory Bowel Disease Are at Increased Risk of Respiratory Syncytial Virus Infections After Severe Acute Respiratory Syndrome Coronavirus 2 Infection: A Propensity-Matched Cohort Analysis

INTRODUCTION

Patients with inflammatory bowel disease (IBD) are at an increased risk of infections. Before the COVID-19 pandemic, respiratory syncytial virus (RSV) followed predictable seasonal patterns, which have been recently disrupted. This study aimed to investigate whether severe acute respiratory syndrome (SARS) coronavirus 2 (CoV-2) infection is associated with an increased risk of RSV infection in patients with IBD compared with those without a history of SARS-CoV-2 infection.

METHODS

This retrospective cohort study used the TriNetX database to identify patients aged 18 years and older with IBD and SARS-CoV-2 infection (IBD-SARS-CoV-2 cohort) during the 2022 and 2023 RSV seasons. A 1:1 propensity score matching was used to compare patients with IBD but no history of SARS-CoV-2 infection (IBD non-SARS-CoV-2 cohort).

RESULTS

In the 2022 IBD-SARS-CoV-2 cohort (mean age: 53.7 ± 17.6 years; 59% female; 77% White), the RSV infection risk was 0.47%, higher than 0.19% in the matched IBD non-SARS-CoV-2 cohort (adjusted odds ratio [aOR]: 2.4; 95% CI: 1.5-3.6). The risk was highest 30-60 days after SARS-CoV-2 infection (aOR: 2.9; 95% CI: 1.7-4.9), particularly in those aged 60 years and older (aOR: 2.5; 95% CI: 1.3-4.5). The use of systemic corticosteroids (aOR: 2.3; 95% CI: 1.1-4.6) or immune-modifying therapies (aOR: 3.9; 95% CI: 2-7.1) was associated with higher RSV infection risk. Similar trends were observed during the 2023 RSV season, with no significant differences in RSV-related hospitalizations.

DISCUSSION

Adults with IBD have a higher risk of RSV infection after SARS-CoV-2 infection, particularly those receiving steroids or immune therapies. SARS-CoV-2 infection may have contributed to the recent RSV infection surge in this population, warranting further research.

Disparities in Respiratory Syncytial Virus Risk Factors, Diagnosis, and Outcomes in Adults by Race, Ethnicity, and Other Social Determinants of Health in the United States

INTRODUCTION

Respiratory syncytial virus (RSV) vaccination could improve health equity by protecting individuals who are disproportionally at increased risk of RSV infection and severe RSV-related outcomes. However, limited information is available about RSV-related disparities among United States (US) adults.

AREAS COVERED

We reviewed US-specific literature regarding disparities across adult populations in having risk factors for severe RSV disease (cardiopulmonary disease, diabetes, liver disease, kidney disease). We summarize available evidence regarding disparities in having or being diagnosed with RSV, as well as experiencing severe RSV-related health outcomes. Disparities are analyzed by race, ethnicity, socioeconomic status, and other social determinants of health.

EXPERT OPINION

RSV-related disparities are observed across all outcomes of interest, although RSV-specific data are limited in some cases. Racial and ethnic minority groups and socioeconomically disadvantaged populations are more likely to have risk factors for severe RSV disease, overall and at younger ages, yet individuals from these groups are more often underdiagnosed. Disparities in RSV-related hospitalizations, emergency department visits, and deaths are observed, especially among adults from racial and ethnic minority groups, of lower socioeconomic status, and in poorer or more crowded neighborhoods. Findings highlight the importance of RSV vaccination among these groups to improve health equity.

Burden of Respiratory Syncytial Virus Disease in Adults with Asthma and Chronic Obstructive Pulmonary Disease: A Systematic Literature Review

PURPOSE OF REVIEW

Accumulating data indicate that asthma and chronic obstructive pulmonary disease (COPD) increase the risk of severe respiratory syncytial virus (RSV) infection. This systematic literature review assessed the burden of RSV disease among adults ≥ 18 years with asthma or COPD.

RECENT FINDINGS

Data on the prevalence of asthma or COPD among RSV-infected adults, RSV-related hospitalizations, complications, and mortality were collected from studies published between January 1, 2000 and November 28, 2023 in PubMed, Embase, and grey literature. All extracted data were analyzed descriptively. Pooled estimates of asthma or COPD prevalence among RSV-infected adults were calculated from generalized linear mixed effects model meta-analyses. Forty studies were included. The prevalence of asthma and COPD among RSV-infected adults was high, especially in inpatient settings with pooled estimates (95% confidence interval) of 19.3% (15.0-24.6) for asthma and 30.8% (26.1-36.0) for COPD. Adults with asthma or COPD were more likely to be hospitalized following RSV infection than those without these conditions. The incidence rate ratios of hospitalization were 2.0-3.6 (crude) and 6.7-8.2 (adjusted) for asthma and 3.2-13.4 (crude) and 9.6-9.7 (adjusted) for COPD. The most frequently reported RSV-related complications were exacerbation of asthma (up to 64.9%) and COPD (up to ≥ 83.0%). In-hospital case fatality rates were 2.6-4.3% (asthma) and 2.8-17.8% (COPD). These comprehensive data showing a high RSV disease burden in adults with asthma or COPD can be used to inform policy decisions around RSV vaccines and improve preventive care in this high-risk population.

Respiratory Syncytial Virus Vaccination in the Adult Pulmonary Patient

TOPIC IMPORTANCE

Since its discovery in 1957, respiratory syncytial virus (RSV) has been widely recognized as a common and deadly pathogen. Although early studies focused on the impact of RSV on the health of children, more recent data show that RSV imposes a significant burden on individuals aged ≥ 70 years. RSV also substantially harms the health of individuals with cardiopulmonary diseases.

REVIEW FINDINGS

Early efforts to develop an RSV vaccine were hampered by toxicity due to antibody-enhanced viral pneumonia and a lack of efficacy in vaccines that targeted the postfusion configuration of the F fusion protein, which is crucial to the pathogenesis of RSV-mediated injury. A newer wave of vaccines has targeted a stabilized prefusion F protein, generating effective neutralizing antibodies and reducing the burden of mild and severe RSV lower respiratory tract injury. This review focuses on the burden of RSV in patients with pulmonary diseases, highlights the tumultuous path from the early days of RSV vaccine development to the modern era, and offers insights into key gaps in knowledge that must be addressed to adequately protect the vulnerable population of patients with severe pulmonary diseases.

SUMMARY

RSV vaccination with bivalent RSVPreF or RSVPreF3OA, which target the stabilized prefusion F protein, can be broadly recommended to adults aged ≥ 60 years with pulmonary diseases. However, more data are needed to understand how these vaccinations affect key clinical outcomes in individuals with pulmonary disease.

Respiratory Syncytial Virus-related Community Chronic Obstructive Pulmonary Disease Exacerbations and Novel Diagnostics: A Binational Prospective Cohort Study

Rationale: Respiratory syncytial virus (RSV) is a common global respiratory virus that is increasingly recognized as a major pathogen in frail older adults and as a cause of chronic obstructive pulmonary disease (COPD) exacerbations. There is no single test for RSV in adults that has acceptable diagnostic accuracy. Trials of RSV vaccines have recently shown excellent safety and efficacy against RSV in older adults; defining the frequency of RSV-related community infections and COPD exacerbations is important for vaccine deployment decisions. Objectives: This prospective study aimed to establish the frequency of outpatient-managed RSV-related exacerbations of COPD in two well-characterized patient cohorts using a combination of diagnostic methods. Methods: Participants were recruited at specialist clinics in London, United Kingdom, and Groningen, the Netherlands, beginning in 2017 and observed for three consecutive RSV seasons, during exacerbations, and at least twice yearly. RSV infections were detected by RT-PCR and serologic testing. Measurements and Main Results: A total of 377 patients with COPD attended 1,999 clinic visits and reported 310 exacerbations. There were 27 RSV-related exacerbations (8.7% of the total); of these, seven were detected only by PCR, 16 only by serology, and four by both methods. Increases in RSV-specific Nucleoprotein antibody were as sensitive as those in the antibody to Pre-Fusion or Post-Fusion for serodiagnosis of RSV-related exacerbations. Conclusions: RSV is associated with 8.7% of outpatient-managed COPD exacerbations in this study. Antibodies to RSV Nucleoprotein may have diagnostic value and are potentially important in a vaccinated population. The introduction of vaccines that prevent RSV is expected to benefit patients with COPD.

Risk factors for severe respiratory syncytial virus-associated respiratory tract infection in a high HIV prevalence setting, South Africa, 2012 - 2018

BACKGROUND

Identifying risk factors for respiratory syncytial virus (RSV)-associated severe acute respiratory illness (SARI) will assist with targeting vaccine interventions.

METHODS

Using surveillance data from South Africa (2012-2018), we compared the characteristics of individuals with RSV-associated influenza-like illness (ILI) (reference group) to those with RSV-associated SARI to describe factors associated with SARI using a multivariable analysis.

RESULTS

RSV was detected in 6% (483/7792) of ILI cases and 15% (844/5672) of SARI cases. Factors associated with SARI in children included age < 2 months, compared to age 2-4 years (adjusted odds ratio (aOR) 54.4; 95% confidence interval (CI) 23.5-125.8), malnutrition (aOR 1.9; 95% CI 1.2-3.2), prematurity (aOR 2.4; 95% CI 1.3-4.6) and living with HIV (LWH) (aOR 22.5; 95% CI 2.9-174.3). In individuals ≥ 5 years, factors associated with SARI included age ≥ 65 years compared to age 5-24 years (aOR 10.7; 95% CI 1.1-107.5), symptom duration ≥ 5 days (aOR 2.7; 95% CI 1.1-6.3), underlying illness (aOR 2.7; 95% CI 1.5-26.1) and LWH (aOR 16.8, 95% CI: 4.8-58.2).

CONCLUSION

Individuals at the extremes of age and those with identified risk factors might benefit most from RSV prevention interventions.

CLINICAL TRIAL NUMBER

Not applicable, this is not a clinical trial.

Respiratory syncytial virus infections in adults: a narrative review

Respiratory syncytial virus (RSV), an RNA virus spread by droplet infection that affects all ages, is increasingly recognised as an important pathogen in adults, especially among older people living with comorbidities. Distinguishing RSV from other acute viral infections on clinical grounds alone, with sufficient precision to be clinically useful, is not possible. The reference standard diagnosis is by PCR: point-of-care tests perform less well with lower viral loads. Testing samples from a single respiratory tract site could result in underdetection. RSV is identified in 6-11% of outpatient respiratory tract infection (RTI) consultations in older adults (≥60 years, or ≥65 years, depending on the study) and accounts for 4-11% of adults (≥18 years) hospitalised with RTI, with 6-15% of those hospitalised admitted to intensive care, and 1-12% of all adults hospitalised with RSV respiratory tract infection dying. Community-based studies estimate the yearly incidence of RSV infection at around 3-7% in adults aged 60 years and older in high-income countries. Although RSV accounts for a similar disease burden as influenza in adults, those hospitalised with severe RSV disease are typically older (most ≥60 years) and have more comorbidities, more respiratory symptoms, and are frequently without fever. Long-term sequelae are common and include deterioration of underlying disease (typically heart failure and COPD). There are few evidence-based RSV-specific treatments currently available, with supportive care being the main modality. Two protein subunit vaccines for protection from severe RSV in adults aged 60 years and older were licensed in 2023, and a third-an mRNA-based vaccine-recently gained market approval in the USA. The phase 3 studies in these three vaccines showed good protection against severe disease. Data on real-world vaccine effectiveness in older adults, including subgroups at high risk for RSV-associated hospitalisation, are needed to establish the best use of these newly approved RSV vaccines. New diagnostics and therapeutics are being developed, which will also need rigorous evaluation within their target populations to ensure they are used only for those in whom there is evidence of improved outcomes. There is an urgent need to reconceptualise this illness from one that is serious in children, but far less important than influenza in older people, to thinking of RSV as also a major risk to health for older people that needs targeted prevention and treatment.

Respiratory Syncytial Virus Infection in Older Adults: An Update

Respiratory syncytial virus (RSV) infection represents one of the most common infections during childhood, with significant morbidity and mortality in newborns and in the early years of life. RSV is a common infection throughout all age groups, largely undetected and underestimated in adults, with a disproportionately high impact in older individuals. RSV infection has a wide range of clinical presentations, from asymptomatic conditions to acute pneumonia and severe life-threatening respiratory distress, including exacerbations of underlying chronic conditions. Overall, the incidence of RSV infections requiring medical attention increases with age, and it is highest among persons ≥ 70 years of age. As a consequence of a combination of an aging population, immunosenescence, and the related increased burden of comorbidities, high-income countries are at risk of developing RSV epidemics. The standard of care for RSV-infected patients remains supportive, including fluids, antipyretics, and oxygen support when needed. There is an urgent need for antivirals and preventive strategies in this population, particularly in individuals at higher risk of severe outcomes following RSV infection. In this review, we describe prevention and treatment strategies for RSV illnesses, with a deep focus on the novel data on vaccination that has become available (Arexvy, GSK, and Abrysvo, Pfizer) for older adults.

Deviations in RSV epidemiological patterns and population structures in the United States following the COVID-19 pandemic

Respiratory Syncytial Virus (RSV) is a leading cause of acute respiratory tract infection, with the greatest impact on infants, immunocompromised individuals, and older adults. RSV prevalence decreased substantially in the United States (US) following the implementation of COVID-19-related non-pharmaceutical interventions but later rebounded with abnormal seasonality. The biological and epidemiological factors underlying this altered behavior remain poorly defined. In this retrospective cohort study from 2009 to 2023 in Chicago, Illinois, US, we examined RSV epidemiology, clinical severity, and genetic diversity. We found that changes in RSV diagnostic platforms drove increased detections in outpatient settings post-2020 and that hospitalized adults infected with RSV-A were at higher risk of intensive care admission than those with RSV-B. While population structures of RSV-A remained unchanged, RSV-B exhibited a genetic shift into geographically distinct clusters. Mutations in the antigenic regions of the fusion protein suggest convergent evolution with potential implications for vaccine and therapeutic development.

From Forgotten Pathogen to Target for New Vaccines: What Clinicians Need to Know about Respiratory Syncytial Virus Infection in Older Adults

Respiratory syncytial virus (RSV) is increasingly recognized as being implicated in acute illness in older adults, with a significant weight in hospitalizations for respiratory illness and death. By means of a best-evidence review, this paper aims to investigate whether RSV can be considered a forgotten pathogen in older patients, looking at trends in the literature volume and exploring possible epidemiological and clinical features underlying the focus given to it. We then present an assessment of its disease burden and present and future strategies for its reduction, particularly in light of the recent availability of new vaccines.

Respiratory Syncytial Virus Vaccination Recommendations for Adults Aged 60 Years and Older: The NeumoExperts Prevention Group Position Paper

Respiratory syncytial virus (RSV) is a major cause of respiratory tract infections in adults, particularly older adults and those with underlying medical conditions. Vaccination has emerged as a potential key strategy to prevent RSV-related morbidity and mortality. This Neumoexperts Prevention (NEP) Group scientific paper aims to provide an evidence-based positioning and RSV vaccination recommendations for adult patients. We review the current literature on RSV burden and vaccine development and availability, emphasising the importance of vaccination in the adult population. According to our interpretation of the data, RSV vaccines should be part of the adult immunisation programme, and an age-based strategy should be preferred over targeting high-risk groups. The effectiveness and efficiency of this practice will depend on the duration of protection and the need for annual or more spaced doses. Our recommendations should help healthcare professionals formulate guidelines and implement effective vaccination programmes for adult patients at risk of RSV infection now that specific vaccines are available.

Altered RSV Epidemiology and Genetic Diversity Following the COVID-19 Pandemic

Respiratory Syncytial Virus (RSV) is a leading cause of acute respiratory tract infection, with greatest impact on infants, immunocompromised individuals, and older adults. RSV prevalence decreased substantially following the implementation of non-pharmaceutical interventions to mitigate the COVID-19 pandemic but later rebounded with initially abnormal seasonality. The biological and epidemiological factors underlying this altered behavior remain poorly defined. In this retrospective cohort study, we examined RSV epidemiology, clinical severity, and genetic diversity in the years surrounding the COVID-19 pandemic. We found that changes in RSV diagnostic platforms drove increased detections in outpatient settings after 2020 and that hospitalized adults with RSV-A were at higher risk of needing intensive care than those with RSV-B. While the population structure of RSV-A remained unchanged, the population structure of RSV-B shifted in geographically distinct clusters. Mutations in the antigenic regions of the fusion protein suggest convergent evolution with potential implications for vaccine and therapeutic development.

An impact of age on respiratory syncytial virus infection in air-liquid-interface culture bronchial epithelium

Background

Elderly people are known to be vulnerable to virus infection. However, this has not been appropriately tested in in vitro studies due to a lack of appropriate virus infection models. In this report, we investigated the impact of age on respiratory syncytial virus (RSV) in pseudostratified air-liquid-interface (ALI) culture bronchial epithelium, which more closely mimic human airway epithelium morphologically and physiologically, than submerged cancer cell line cultures.

Methods

RSV A2 was inoculated apically to the bronchial epithelium obtained from 8 donors with different ages (28–72 years old), and time-profiles of viral load and inflammatory cytokines were analyzed.

Results

RSV A2 replicated well in ALI-culture bronchial epithelium. The viral peak day and peak viral load were similar between donors at ≤60 years old (n = 4) and  &gt; 65 years old (n = 4; elderly group), but virus clearance was impaired in the elderly group. Furthermore, area under the curve (AUC) analysis, calculated from viral load peak to the end of sample collection (from Day 3 to 10 post inoculation), revealed statistically higher live viral load (PFU assay) and viral genome copies (PCR assay) in the elderly group, and a positive correlation between viral load and age was observed. In addition, the AUCs of RANTES, LDH, and dsDNA (cell damage marker) were statistically higher in the elderly group, and the elderly group showed a trend of higher AUC of CXCL8, CXCL10 and mucin production. The gene expression of p21CDKN1A (cellular senescence marker) at baseline was also higher in the elderly group, and there was a good positive correlation between basal p21 expression and viral load or RANTES (AUC).

Conclusion

Age was found to be a key factor affecting viral kinetics and biomarkers post virus infection in an ALI-culture model. Currently, novel or innovative in vitro cell models are introduced for virus research, but when virus studies are conducted, similarly to working with other clinical samples, the age balance is important to obtain more accurate results.

Targeted Literature Review of the Burden of Respiratory Syncytial Infection among High-Risk and Elderly Patients in Asia Pacific Region

INTRODUCTION

The burden of respiratory syncytial virus (RSV), which causes acute respiratory illness, is well recognized among the pediatric population but also imposes a significant risk to the elderly (age ≥ 60) and those with underlying comorbidities. The study aimed to review the most recent data on epidemiology and burden (clinical and economic) of RSV in the elderly/high-risk populations in China, Japan, South Korea, Taiwan, and Australia.

METHODS

A targeted review was conducted of English, Japanese, Korean, and Chinese language articles published from 1 January 2010 to 7 October 2020 relevant for the purpose.

RESULTS

A total of 881 studies were identified, and 41 were included. The median proportion of elderly patients with RSV in all adult patients with acute respiratory infection (ARI) or community acquired pneumonia was 79.78% (71.43-88.12%) in Japan, 48.00% (3.64-80.00%) in China, 41.67% (33.33-50.00%) in Taiwan, 38.61% in Australia, and 28.57% (22.76-33.33%) in South Korea. RSV was associated with a high clinical burden on those patients with comorbidities such as asthma and chronic obstructive pulmonary disease. In China, inpatients with ARI showed a significantly higher rate of RSV-related hospitalization than outpatients (13.22% versus 4.08%, p < 0.01). The median length of hospital stay among elderly patients with RSV was longest in Japan (30 days) and shortest in China (7 days). Mortality data varied by region with some studies reporting rates as high as 12.00% (9/75) in hospitalized elderly patients. Finally, data on the economic burden was only available for South Korea, with the median cost of a medical admission for an elderly patient with RSV being US dollar (USD) 2933.

CONCLUSION

RSV infection is a major source of disease burden among elderly patients, especially in regions with aging populations. It also complicates the management of those with underlying diseases. Appropriate prevention strategies are required to reduce the burden among the adult, especially the elderly, population. Data gaps regarding economic burden of RSV infection in the Asia Pacific region indicates the need for further research to increase our understanding on the burden of this disease in this region.

Respiratory Syncytial Virus Prefusion F Protein Vaccine in Older Adults

BACKGROUND

Respiratory syncytial virus (RSV) is an important cause of acute respiratory infection, lower respiratory tract disease, clinical complications, and death in older adults. There is currently no licensed vaccine against RSV infection.

METHODS

In an ongoing, international, placebo-controlled, phase 3 trial, we randomly assigned, in a 1:1 ratio, adults 60 years of age or older to receive a single dose of an AS01_E-adjuvanted RSV prefusion F protein-based candidate vaccine (RSVPreF3 OA) or placebo before the RSV season. The primary objective was to show vaccine efficacy of one dose of the RSVPreF3 OA vaccine against RSV-related lower respiratory tract disease, confirmed by reverse-transcriptase polymerase chain reaction (RT-PCR), during one RSV season. The criterion for meeting the primary objective was a lower limit of the confidence interval around the efficacy estimate of more than 20%. Efficacy against severe RSV-related lower respiratory tract disease and RSV-related acute respiratory infection was assessed, and analyses according to RSV subtype (A and B) were performed. Safety was evaluated.

RESULTS

A total of 24,966 participants received one dose of the RSVPreF3 OA vaccine (12,467 participants) or placebo (12,499). Over a median follow-up of 6.7 months, vaccine efficacy against RT-PCR-confirmed RSV-related lower respiratory tract disease was 82.6% (96.95% confidence interval [CI], 57.9 to 94.1), with 7 cases (1.0 per 1000 participant-years) in the vaccine group and 40 cases (5.8 per 1000 participant-years) in the placebo group. Vaccine efficacy was 94.1% (95% CI, 62.4 to 99.9) against severe RSV-related lower respiratory tract disease (assessed on the basis of clinical signs or by the investigator) and 71.7% (95% CI, 56.2 to 82.3) against RSV-related acute respiratory infection. Vaccine efficacy was similar against the RSV A and B subtypes (for RSV-related lower respiratory tract disease: 84.6% and 80.9%, respectively; for RSV-related acute respiratory infection: 71.9% and 70.6%, respectively). High vaccine efficacy was observed in various age groups and in participants with coexisting conditions. The RSVPreF3 OA vaccine was more reactogenic than placebo, but most adverse events for which reports were solicited were transient, with mild-to-moderate severity. The incidences of serious adverse events and potential immune-mediated diseases were similar in the two groups.

CONCLUSIONS

A single dose of the RSVPreF3 OA vaccine had an acceptable safety profile and prevented RSV-related acute respiratory infection and lower respiratory tract disease and severe RSV-related lower respiratory tract disease in adults 60 years of age or older, regardless of RSV subtype and the presence of underlying coexisting conditions. (Funded by GlaxoSmithKline Biologicals; AReSVi-006 ClinicalTrials.gov number, NCT04886596.).

A prefusion-stabilized RSV F subunit vaccine elicits B cell responses with greater breadth and potency than a postfusion F vaccine

There is currently no licensed vaccine for respiratory syncytial virus (RSV). Here, we assess the effect of RSV fusion protein (F) conformation on B cell responses in a post hoc comparison of samples from the DS-Cav1 [prefusion (pre-F)] and MEDI7510 [postfusion (post-F)] vaccine clinical trials. We compared the magnitude and quality of the serological and B cell responses across time points and vaccines. We measured RSV A and B neutralization, F-binding immunoglobulin G titers, and competition assays at week 0 (before vaccination) and week 4 (after vaccination) to evaluate antibody specificity and potency. To compare B cell specificity and activation, we used pre-F and post-F probes in tandem with a 17-color immunophenotyping flow cytometry panel at week 0 (before vaccination) and week 1 (after vaccination). Our data demonstrate that both DS-Cav1 and MEDI7510 vaccination robustly elicit F-specific antibodies and B cells, but DS-Cav1 elicited antibodies that more potently neutralized both RSV A and B. The superior potency was mediated by antibodies that bind antigenic sites on the apex of pre-F that are not present on post-F. In the memory (CD27+) B cell compartment, vaccination with DS-Cav1 or MEDI7510 elicited B cells with different epitope specificities. B cells preferentially binding the pre-F probe were activated in DS-Cav1-vaccinated participants but not in MEDI7510-vaccinated participants. Our findings emphasize the importance of using pre-F as an immunogen in humans because of its deterministic role in eliciting highly potent neutralizing antibodies and memory B cells.

Going Viral-RSV as the Neglected Adult Respiratory Virus

Human respiratory syncytial virus (RSV) is increasingly recognized as a significant viral pathogen in adults with acute respiratory illness, particularly in the elderly, the immunocompromised, and those with underlying cardiopulmonary disease. Although long acknowledged as one of the most common causes of upper respiratory tract infections (URI) in children since its discovery in 1956, the true burden of disease in adults is likely significantly under-recognized. The emerging evidence of RSV as a driver of morbidity and mortality in elderly and immunocompromised patients has sparked advances in vaccine development and renewed interest in quantifying the true burden of disease. This review attempts to summarize the findings of the most recent evidence investigating the burden of RSV related disease in adults and to highlight where future research is needed.

Impact of respiratory viral infections on mortality and critical illness among hospitalized patients with chronic obstructive pulmonary disease

BACKGROUND

Seasonal respiratory viral infections are associated with exacerbations and morbidity among patients with COPD. The real-world clinical outcomes associated with seasonal viral infections are less well established among hospitalized patients.

RESEARCH QUESTION

To estimate the association between seasonal respiratory viral infections, 30-day mortality, and intensive care unit (ICU) admission among hospitalized COPD patients.

STUDY DESIGN AND METHODS

We conducted an analysis of a national prospective multicenter cohort of COPD patients hospitalized with acute respiratory illness during winter seasons (2011-2015) in Canada. Nasopharyngeal swabs were performed on all patients at the onset of hospital admission for diagnosis of viral infection. Primary outcomes were 30-day mortality and ICU admissions. Secondary outcomes included invasive/non-invasive ventilation use.

RESULTS

Among 3931 hospitalized patients with COPD, 28.5% (1122/3931) were diagnosed with seasonal respiratory viral infection. Viral infection was associated with increased admission to ICU (OR 1.5, 95% CI 1.2-1.9) and need for mechanical ventilation (OR 1.9, 95% CI 1.4-2.5), but was not associated with mortality (OR 1.1, 95% CI 0.8-1.4). Patients with respiratory syncytial virus (RSV) were equally likely to require ICU admission (OR 1.09, 95% CI 0.67-1.78), and more likely to need non-invasive ventilation (OR 3.1; 95% CI 1.8-5.1) compared to patients with influenza.

INTERPRETATION

Our results suggest COPD patients requiring hospitalization for respiratory symptoms should routinely receive viral testing at admission, especially for RSV and influenza, to inform prognosis, clinical management, and infection control practices during winter seasons. Patients with COPD will be an important target population for newly developed RSV therapeutics.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT01517191.

Clinical Outcome of Viral Respiratory Tract Infections in Hospitalized Adults in Norway: High Degree of Inflammation and Need of Emergency Care for Cases With Respiratory Syncytial Virus

Background

The clinical features and outcomes of viral respiratory tract infections (RTIs) in adults have not been thoroughly studied, especially the respiratory syncytial virus (RSV) disease burden. It has become apparent that outbreaks of RSV in the elderly are associated with increased hospitalization rates. However, little data exists on the severity of such viral RTIs in adults, particularly the need for hospitalization, respiratory support and intensive care.

Methods

We conducted a retrospective observational single-center study at Østfold Hospital Trust, Norway, during three winter seasons 2015–2018. Patients ≥18 years with either influenza A, influenza B, RSV A/B, human metapneumovirus, parainfluenza virus 1–4 or adenovirus detected in respiratory specimens were included, if they were hospitalized 14 days prior or following the detection date, with signs of RTI. Hospital records on treatment and outcome were investigated, as well as mortality of all causes up to 30 days from discharge.

Results

Of the 1222 infection events that were included, influenza A was the most frequent virus detected (39%), while 179 infection events (14.6%) were due to RSV. Influenza B counted for 24% of the infection events, human metapneumovirus 13%, parainfluenza virus 9% and adenovirus 1%. Patients admitted with RSV more often suffered from COPD and congestive heart failure than patients with influenza A. In addition, RSV patients were overrepresented in the urgent response NEWS score (National Early Warning Score) category ≥5. RSV patients also showed signs of more severe inflammation, with WBC ≥11.1 × 10⁹/L and CRP >100 mg/L, and they were more often treated with antibiotic agents during their hospital stay. However, we found no differences in the need for ICU admission or mortality.

Conclusion

Patients with RSV had more often high values for markers of inflammation and elevated NEWS score when compared to patients hospitalized with other common respiratory viruses. Taken into account that they suffered more frequently from comorbidities like COPD, these patients needed hospitalization more urgently. These findings highlight the need for further investigations on RSV disease in adults and the elderly.

Rates of respiratory syncytial virus (RSV)-associated hospitalization among adults with congestive heart failure—United States, 2015–2017

Background

Respiratory syncytial virus (RSV) can cause severe disease in adults with cardiopulmonary conditions, such as congestive heart failure (CHF). We quantified the rate of RSV-associated hospitalization in adults by CHF status using population-based surveillance in the United States.

Methods

Population-based surveillance for RSV (RSV-NET) was performed in 35 counties in seven sites during two respiratory seasons (2015–2017) from October 1–April 30. Adults (≥18 years) admitted to a hospital within the surveillance catchment area with laboratory-confirmed RSV identified by clinician-directed testing were included. Presence of underlying CHF was determined by medical chart abstraction. We calculated overall and age-stratified (<65 years and ≥65 years) RSV-associated hospitalization rates by CHF status. Estimates were adjusted for age and the under-detection of RSV. We also report rate differences (RD) and rate ratios (RR) by comparing the rates for those with and without CHF.

Results

2042 hospitalized RSV cases with CHF status recorded were identified. Most (60.2%, n = 1230) were ≥65 years, and 28.3% (n = 577) had CHF. The adjusted RSV hospitalization rate was 26.7 (95% CI: 22.2, 31.8) per 10,000 population in adults with CHF versus 3.3 (95% CI: 3.3, 3.3) per 10,000 in adults without CHF (RR: 8.1, 95% CI: 6.8, 9.7; RD: 23.4, 95% CI: 18.9, 28.5). Adults with CHF had higher rates of RSV-associated hospitalization in both age groups (<65 years and ≥65 years). Adults ≥65 years with CHF had the highest rate (40.5 per 10,000 population, 95% CI: 35.1, 46.6).

Conclusions

Adults with CHF had 8 times the rate of RSV-associated hospitalization compared with adults without CHF. Identifying high-risk populations for RSV infection can inform future RSV vaccination policies and recommendations.

Respiratory Syncytial Virus

Human respiratory syncytial virus (RSV) is a negative sense single-stranded RNA virus that can result in epidemics of seasonal respiratory infections. Generally, one of the two genotypes (A and B) predominates in a single season and alternate annually with regional variation. RSV is a known cause of disease and death at both extremes of ages in the pediatric and elderly, as well as immunocompromised populations. The clinical impact of RSV on the hospitalized adults has been recently clarified with the expanded use of multiplex molecular assays. Among adults, RSV can produce a wide range of clinical symptoms due to upper respiratory tract infections potentially leading to severe lower respiratory tract infections, as well as exacerbations of underlying cardiac and lung diseases. While supportive care is the mainstay of therapy, there are currently multiple therapeutic and preventative options under development.

Contact With Young Children Increases the Risk of Respiratory Infection in Older Adults in Europe-the RESCEU Study

Background

Knowledge about how older adults get a respiratory infection is crucial for planning preventive strategies. We aimed to determine how contact with young children living outside of the household affects the risk of acute respiratory tract infections (ARTI) in community-dwelling older adults.

Methods

This study is part of the European RESCEU older adult study. Weekly surveillance was performed to detect ARTI throughout 2 winter seasons (2017-2018, 2018-2019). Child exposure, defined as having regular contact with children under 5 living outside of the subject’s household, was assessed at baseline. The average attributable fraction was calculated to determine the fraction of ARTI explained by exposure to these children.

Results

We prospectively established that 597/1006 (59%) participants experienced at least 1 ARTI. Child exposure increased the risk of all-cause ARTI (adjusted odds ratio [aOR], 1.58; 95% confidence interval [CI], 1.21 -2.08; P = .001). This risk was highest in those with the most frequent contact (aOR, 1.80; 95% CI, 1.23-2.63; P = .003). The average attributable fraction of child exposure explaining ARTI was 10% (95% CI, 5%-15%).

Conclusions

One of 10 ARTI in community-dwelling older adults is attributable to exposure to preschool children living outside of the household.

Clinical Trials Registration

NCT03621930.

Occurrence and disease burden of respiratory syncytial virus and other respiratory pathogens in adults aged ≥65 years in community: A prospective cohort study in Japan

Background

The frequency and clinical profile of respiratory syncytial virus (RSV)–acute respiratory disease (ARD) in older adults in Japan has not been well‐characterized.

Methods

This was a multicenter prospective observational cohort study to evaluate the occurrence rate of ARD in 1000 older adult participants (≥65 years) for 52 weeks during the 2019 to 2020 season. A multiplex polymerase chain reaction panel was used for pathogen detection in nasopharyngeal swab from participants diagnosed with ARD. Symptoms and impact of ARD was assessed using the Respiratory Infection Intensity and Impact Questionnaire (RiiQ™). The study was registered at UMIN (https://www.umin.ac.jp/ctr/): UMIN000037891.

Results

RSV–ARD was detected in 24/1000 (2.4%) participants and RSV‐lower respiratory tract disease in 8/1000 (0.8%) participants. The median duration of RSV–ARD was 18 days. All 24 participants had utilized the medical services of outpatient visits and only 1 (4.2%) participant was hospitalized for RSV–ARD. The most common viruses other than RSV that caused ARD (detected in >10 participants) were human rhinovirus/enterovirus, parainfluenza 3, coronavirus OC43, human metapneumovirus, and influenza A/H1. The most frequent symptoms of RSV–ARD were cough, sore throat, nasal congestion, and expectoration.

Conclusions

RSV was reported as a major pathogen for respiratory infections in older adults in Japan.

Respiratory Viruses in Acute Exacerbations of Bronchiectasis

BACKGROUND

Bacterial infections are well known factors underlying acute exacerbations in bronchiectasis. However, viral infections may also contribute to acute exacerbations. We aimed to assess the rate of viral detection in acute exacerbations of bronchiectasis, and the associated clinical factors.

METHODS

Diagnostic tests for viral and bacterial etiologies were performed in 792 patients with bronchiectasis who visited the emergency room or the respiratory care inpatient unit in a tertiary referral center in South Korea. All patients were diagnosed with bronchiectasis by chest computerized tomography and were prescribed antibiotics for a minimum of 3 days.

RESULTS

Viral pathogens were detected in 202 of the 792 enrolled patients (25.5%). The most common viral pathogen isolated was influenza A virus (24.8%), followed by rhinovirus (22.4%), influenza B virus (9.8%), respiratory syncytial virus B (8.9%), and human metapneumovirus (6.1%). In 145 patients, a viral, but not bacterial, pathogen was detected, whereas no pathogens were found in 443 patients with exacerbations. Multivariable analysis revealed that female sex and chronic heart disease as a comorbidity were positively associated with viral detection in acute exacerbations of patients with bronchiectasis, whereas the presence of radiographic infiltration was negatively associated.

CONCLUSION

Respiratory viruses were identified in approximately 25% of the acute exacerbations observed among patients with bronchiectasis. Of the viruses detected, influenza viruses and rhinovirus made up over 50%. More attention to viruses as possible causative pathogens for acute deteriorating symptoms in patients with bronchiectasis is warranted.

In-hospital and midterm out-hospital complications of adults hospitalised with respiratory syncytial virus infection in France, 2017-2019: an observational study

OBJECTIVES

To describe the clinical characteristics and in/out-hospital outcomes of respiratory syncytial virus (RSV) infection among adults hospitalised with influenza-like illness (ILI) and compared against patients admitted for influenza.

METHODS

Adults hospitalised with ILI were prospectively included from five French university hospitals over two consecutive winter seasons (2017/2018 and 2018/2019). RSV and influenza virus were detected by multiplex RT-PCR on nasopharyngeal swabs. RSV-positive patients were compared to RSV-negative and influenza-positive hospitalised patients. Poisson regression models were used to estimate the adjusted prevalence ratio (aPR) associated with in-hospital and post-discharge outcomes between RSV and influenza infections. The in-hospital outcome was a composite of the occurrence of at least one complication, length of stay ≥7 days, intensive care unit (ICU) admission, use of mechanical ventilation and in-hospital death. Post-discharge outcome included 30/90-day all-cause mortality and 90-day readmission rates.

RESULTS

Overall, 1,428 hospitalised adults with ILI were included. RSV was detected in 8% (114/1428) and influenza virus in 31% (437/1428). Patients hospitalised with RSV were older than those with influenza (mean age, 73.0 versus 68.8 years; p=0.015) with a higher frequency of respiratory (52% versus 39%, p=0.012) or cardiac chronic diseases (52% versus 41%, p=0.039) and longer hospitalisation duration (median stay 8 versus 6 days, p<0.001). Anti-influenza therapies were less prescribed among RSV than influenza patients (20% versus 66%, p<0.001). In-hospital composite outcome was poorer in RSV patients (adjusted prevalence ratio (aPR)=1.5; 95% Confidence Interval (95% CI) 1.1-2.1) than in those hospitalised with influenza. No difference was observed for the post-discharge composite outcome (aPR=1.1; 95% CI 0.8-1.6).

CONCLUSION

RSV infection results in serious respiratory illness with in-hospital outcomes worse than influenza and with similar midterm post-discharge outcomes.

Underlying cardiopulmonary conditions as a risk factor for influenza and respiratory syncytial virus infection among community-dwelling adults aged ≥ 65 years in Thailand: Findings from a two-year prospective cohort study

Background

Adults with cardiopulmonary conditions may be at increased risk of influenza and respiratory syncytial virus (RSV) infection, but it is not well‐established and few data are available from middle‐income countries.

Methods

Using data from a prospective cohort study of influenza vaccine effectiveness, we estimated and compared the incidences of influenza and RSV between community‐dwelling Thai adults aged ≥ 65 years with and without cardiopulmonary conditions. During May 2015‐May 2017, older adults in a rural province in Thailand were followed‐up with weekly surveillance for acute respiratory illness (ARI), defined broadly as new onset or worsening of cough with or without fever, and hospitalized ARI. When ill, nasal self‐swabs and/or nasopharyngeal swabs were collected for reverse‐transcription polymerase chain reaction testing. We used Poisson regression to calculate incidence rate ratios (IRR), adjusting for age, sex, current smoking, number of hospital visits, weekly influenza activity, and influenza vaccination.

Results

Overall, 3220 adults with a median age of 71 years (IQR 68‐76) were enrolled; 1324 (41.1%) were male; and 313 (9.7%) had ≥1 underlying cardiopulmonary condition, most commonly chronic obstructive pulmonary disease (131; 41.2%) or asthma (73; 23.3%). Participants with cardiopulmonary conditions had higher incidences of ARI, influenza, and RSV than those without (Adjusted IRR: 1.84, 95% CI 1.64‐2.07; 1.86, 95% CI 1.07‐3.26; 2.04, 95% CI 1.11‐3.76, respectively).

Conclusion

Older adults in rural Thailand with cardiopulmonary conditions have increased rates of ARI, influenza, and RSV infections. Our findings support efforts to ensure this population has access to influenza vaccines and other respiratory illness prevention measures.

The Effect of Unconventional Cytokine Combinations on NK-Cell Responses to Viral Infection

Cytokines are soluble and membrane-bound factors that dictate immune responses. Dogmatically, cytokines are divided into families that promote type 1 cell-mediated immune responses (e.g., IL-12) or type 2 humoral responses (e.g., IL-4), each capable of antagonizing the opposing family of cytokines. The discovery of additional families of cytokines (e.g., IL-17) has added complexity to this model, but it was the realization that immune responses frequently comprise mixtures of different types of cytokines that dismantled this black-and-white paradigm. In some cases, one type of response may dominate these mixed milieus in disease pathogenesis and thereby present a clear therapeutic target. Alternatively, synergistic or blended cytokine responses may obfuscate the origins of disease and perplex clinical decision making. Most immune cells express receptors for many types of cytokines and can mediate a myriad of functions important for tolerance, immunity, tissue damage, and repair. In this review, we will describe the unconventional effects of a variety of cytokines on the activity of a prototypical type 1 effector, the natural killer (NK) cell, and discuss how this may impact the contributions of these cells to health and disease.

Severe Morbidity and Short- and Mid- to Long-term Mortality in Older Adults Hospitalized with Respiratory Syncytial Virus Infection

BACKGROUND

We describe the clinical epidemiology and outcomes among a large cohort of older adults hospitalized with respiratory syncytial virus (RSV) infection in the United States.

METHODS

Hospitalized adults aged ≥60 years who tested positive for RSV between 1 January 2011 and 30 June 2015 were identified from Kaiser Permanente Southern California. Patient-level demographics, comorbidities, clinical presentation, utilization, complications, and mortality were evaluated.

RESULTS

There were 664 patients hospitalized with RSV (61% female, 64% aged ≥75 years). Baseline chronic diseases were prevalent (all >30%); 66% developed pneumonia, 80% of which were radiographically confirmed. Very severe tachypnea (≥26 breaths/minute) was common (56%); 21% required ventilator support and 18% were admitted to intensive care unit. Mortality during hospitalization was 5.6% overall (4.6% in 60-74 year olds and 6.1% in ≥75 year olds). Cumulative mortality within 1, 3, 6, and 12 months of admission was 8.6%, 12.3%, 17.2%, and 25.8%, respectively.

CONCLUSION

RSV infection in hospitalized older adults often manifested as severe, life-threatening lower respiratory tract illness with high rates of pneumonia, requirement for ventilatory support, and short- and long-term mortality. Increased recognition of the substantial RSV disease burden in adults will be important in evaluation and use of urgently needed interventions.

Bronchial Variation: Anatomical Abnormality May Predispose Chronic Obstructive Pulmonary Disease

Noxious particulate matter in the air is a primary cause of chronic obstructive pulmonary disease (COPD). The bronchial tree acts to filter these materials in the air and preserve the integrity of the bronchi. Accumulating evidence has demonstrated that smoking and air pollutants are the most prominent risk factors of COPD. Bifurcations in the airway may act as deposition sites for the retention of inhaled particles, however, little is known concerning the impacts of abnormalities of the bronchial anatomy in the pathogenesis of COPD. Studies have reported significant associations between bronchial variations and the symptoms in COPD. In particular, it has been shown that bronchial variations in the central airway tree may contribute to the development of COPD. In this review, we identified three common types of bronchial variation that were used to formulate a unifying hypothesis to explain how bronchial variations contribute to the development of COPD. We also investigated the current evidence for the involvement of specific genes including fibroblast growth factor 10 (Fgf10) and bone morphogenetic protein 4 (Bmp4) in the formation of bronchial variation. Finally, we highlight novel assessment strategies and opportunities for future research of bronchial variations and genetic susceptibility in COPD and comorbidities. Our data strongly highlight the role of bronchial variations in the development, complications, and acute exacerbation of COPD.

Morbidity and mortality of respiratory syncytial virus infection in hospitalized adults: Comparison with seasonal influenza

INTRODUCTION

Respiratory syncytial virus (RSV) is considered a major pathogen that causes acute influenza-like illness. The objective of this study was to compare the clinical outcomes of patients with laboratory-confirmed RSV and patients with influenza infection.

METHODS

Adults hospitalized in Beilinson Hospital (October 2017-April 2018) with laboratory-confirmed RSV or influenza were included. The primary outcome was the composite of RSV/influenza complications: 30-day mortality, pneumonia, mechanical ventilation, vasopressor support, intensive care unit admission, and myocarditis/encephalitis. Secondary outcomes were individual components of the primary outcome, 90-day mortality, 90-day readmission, and length of hospital stay.

RESULTS

A total of 639 patients with RSV (n = 113) and influenza (n = 526) were included. The composite primary outcome was 21.4% (136/633), and was higher in RSV patients (30% (34/113) vs 19% (102/526), p = 0.002). Pneumonia was more common in RSV patients (21.2% (24/113) vs 9.1% (48/526), p = 0.001). On multivariable analysis, hypoalbuminemia (odds ratio (OR) 3.3, 95% confidence interval (CI) 2.1-5.3, p < 0.001), reduced room-air saturation (OR 1.1, 95% CI 1.02-1.1, p = 0.001), and infection with RSV (OR 1.67, 95% CI 1.01-2.76, p = 0.046) were predictors of complications.

CONCLUSIONS

RSV infection in hospitalized adults resulted in serious respiratory illness with complications that are comparable to those caused by influenza.

Safety and Antiviral Effects of Nebulized PC786 in a Respiratory Syncytial Virus Challenge Study

Background

PC786 is a nebulized nonnucleoside respiratory syncytial virus (RSV) polymerase inhibitor designed to treat RSV, which replicates in the superficial layer of epithelial cells lining the airways.

Methods

Fifty-six healthy volunteers inoculated with RSV-A (Memphis 37b) were randomly dosed with either nebulized PC786 (5 mg) or placebo, twice daily for 5 days, from either 12 hours after confirmation of RSV infection or 6 days after virus inoculation. Viral load (VL), disease severity, pharmacokinetics, and safety were assessed until discharge. RSV infection was confirmed by reverse-transcription quantitative polymerase chain reaction with any positive value (intention-to-treat infected [ITT-I] population) or RSV RNA ≥1 log₁₀ plaque-forming unit equivalents (PFUe)/mL (specific intention-to-treat infection [ITT-IS] population) in nasal wash samples.

Results

In the ITT-I population, the mean VL area under the curve (AUC) was lower in the PC786 group than the placebo group (274.1 vs 406.6 log₁₀ PFUe/mL × hour; P = .0359). PC786 showed a trend toward reduction of symptom score and mucous weight. In ITT-IS (post hoc analysis), the latter was statistically significant as well as VL AUC (P = .0126). PC786 showed an early time to maximum plasma concentration, limited systemic exposure, and long half-life and consequently a 2-fold accumulation over the 5-day dosing period. PC786 was well tolerated.

Conclusions

Nebulized PC786 demonstrated a significant antiviral effect against RSV, warranting further clinical study.

Clinical Trials Registration

ClinicalTrials.gov: NCT03382431; EudraCT: 2017-002563-18.

Molecular epidemiology of human respiratory syncytial virus (HRSV) in Iranian military trainees with acute respiratory symptoms in 2017

Background and Objectives

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infection in many populations, including military recruits receiving basic training. Therefore, this study was set out to determine the molecular epidemiology, genotype and phylogenetic features of RSVs in patients with respiratory infection as a case study.

Materials and Methods

In this study, military barracks of Tehran, Iran, between January to March 2017 exposed to respiratory diseases were used for sampling. Throat swabs were taken, a reverse transcriptase-polymerase chain reaction (RTPCR) assay was performed to identify RSV and then the genotyping and phylogenetic analyses of RSVs in patients with a respiratory infection.

Results

Among 400 Iranian military trainees with respiratory symptoms, RSV infection was identified in 2.75% (11/400) using RT-PCR. Sequencing showed the incidence of type A (2.5%, n=10) to be much higher than type B (0.25%, n=1); Sore throat was the most common symptom among RSV patients. Phylogenetic analysis revealed that the majority of strains from the studied samples were more consistent with those from the Philippines and the US strains.

Conclusion

This study is the first to document RSV as a major cause of acute respiratory illness among military trainees in Iran. The prevalence of RSV is substantial in the cold season and the prevalence of genotype A is dominant in the country, leading to take essential steps in preparing a preventive vaccine against this viral infection.

T-Cell Responses in Adults During Natural Respiratory Syncytial Virus Infection

Background

The pathogenesis of respiratory syncytial virus (RSV) in older adults may be due to age-related T-cell immunosenescence. Thus, we evaluated CD4 and CD8 T-cell responses during RSV infection in adults across the age spectrum.

Methods

Peripheral blood mononuclear cells collected during RSV infection in adults, age 26-96 years, were stimulated with live RSV and peptide pools representing F, M, NP, and G proteins and analyzed by flow cytometry.

Results

There were no significant age-related differences in frequency of CD4+ T cells synthesizing interferon (IFN)γ, interleukin (IL)2, IL4, IL10, or tumor necrosis factor (TNF)α or in CD8+IFNγ+ T cells. IL4+CD4+ T-cell numbers were low, as were IL13 and IL17 responses. However, in univariate analysis, CD4 T-cell IFNγ, IL2, IL4, IL10, and TNFα responses and CD8+IFNγ+ T cells were significantly increased with more severe illness requiring hospitalization. In multivariate analysis, viral load was also associated with increased T-cell responses.

Conclusions

We found no evidence of diminished RSV-specific CD4 or CD8 T-cell responses in adults infected with RSV. However, adults with severe disease seemed to have more robust CD4 and CD8 T-cell responses during infection, suggesting that disease severity may have a greater association with T-cell responses than age.

Host Components Contributing to Respiratory Syncytial Virus Pathogenesis

Respiratory syncytial virus (RSV) is the most prevalent viral etiological agent of acute respiratory tract infection. Although RSV affects people of all ages, the disease is more severe in infants and causes significant morbidity and hospitalization in young children and in the elderly. Host factors, including an immature immune system in infants, low lymphocyte levels in patients under 5 years old, and low levels of RSV-specific neutralizing antibodies in the blood of adults over 65 years of age, can explain the high susceptibility to RSV infection in these populations. Other host factors that correlate with severe RSV disease include high concentrations of proinflammatory cytokines such as interleukins (IL)-6, IL-8, tumor necrosis factor (TNF)-α, and thymic stromal lymphopoitein (TSLP), which are produced in the respiratory tract of RSV-infected individuals, accompanied by a strong neutrophil response. In addition, data from studies of RSV infections in humans and in animal models revealed that this virus suppresses adaptive immune responses that could eliminate it from the respiratory tract. Here, we examine host factors that contribute to RSV pathogenesis based on an exhaustive review of in vitro infection in humans and in animal models to provide insights into the design of vaccines and therapeutic tools that could prevent diseases caused by RSV.

Respiratory syncytial virus infection in adults

Human respiratory syncytial virus (RSV) belongs to the recently defined Pneumoviridae family, Orthopneumovirus genus. It is a negative sense, single stranded RNA virus that results in epidemics of respiratory infections that typically peak in the winter in temperate climates and during the rainy season in tropical climates. Generally, one of the two genotypes (A and B) predominates in a single season, alternating annually, although regional variation occurs. RSV is a cause of disease and death in children, older people, and immunocompromised patients, and its clinical effect on adults admitted to hospital is clarified with expanded use of multiplex molecular assays. Among adults, RSV produces a wide range of clinical symptoms including upper respiratory tract infections, severe lower respiratory tract infections, and exacerbations of underlying disease. Here we discuss the latest evidence on the burden of RSV related disease in adults, especially in those with immunocompromise or other comorbidities. We review current therapeutic and prevention options, as well as those in development.

Cigarette smoking and the occurrence of influenza - Systematic review

OBJECTIVES

The association of current smoking with influenza infection is not widely recognised. The aim of this systematic review was to summarise published evidence and quantify the risk of influenza infection in tobacco smokers compared to non-smokers.

METHODS

We systematically searched MEDLINE, EMBASE, CINAHL, LILACS and Web of Science, from inception to 7 November 2017, to identify relevant randomised control trials, cohort and case-control studies. Study quality was assessed using the Newcastle-Ottawa Scale. We included studies defining influenza as a clinical syndrome and those using confirmatory microbiological tests. Pooled odds ratios (ORs) were estimated by using random effects model.

RESULTS

The mean quality score across the nine included studies (n = 40,685 participants) was 5.4 of 9 (SD 1.07). Current smokers were over 5 times more likely to develop laboratory-confirmed influenza than non-smokers (pooled OR 5.69 (95% CI 2.79-11.60), 3 studies). For studies reporting the occurrence of an influenza-like illness (ILI), current smokers were 34% more likely to develop ILI than non-smokers (pooled OR 1.34 (95% CI 1.13-1.59), 6 studies).

CONCLUSION

Current smokers have an increased risk of developing influenza compared to non-smokers. The association was strongest in studies examining cases with laboratory confirmed influenza.

Respiratory Syncytial Virus and Associations With Cardiovascular Disease in Adults

Respiratory syncytial virus (RSV) is historically known for causing respiratory illness in young children, but the appreciation of its impact on older adults is growing. Studies have shown that hospitalization for respiratory illness due to RSV is complicated by cardiovascular events in 14% to 22% of adult patients, including worsening congestive heart failure, acute coronary syndrome, and arrhythmias. Additionally, underlying cardiovascular disease is associated with hospitalization in 45% to 63% of adults with confirmed RSV. In summary, patients with cardiopulmonary disease have higher rates of health care utilization for RSV-related illness and worse outcomes. Patients with cardiovascular disease likely represent an important target population for the rapidly developing field of RSV vaccines.

Respiratory viral infection: a potential "missing link" in the pathogenesis of COPD

Chronic obstructive pulmonary disease (COPD) is currently the third most common cause of global mortality. Acute exacerbations of COPD frequently necessitate hospital admission to enable more intensive therapy, incurring significant healthcare costs. COPD exacerbations are also associated with accelerated lung function decline and increased risk of mortality. Until recently, bacterial pathogens were believed to be responsible for the majority of disease exacerbations. However, with the advent of culture-independent molecular diagnostic techniques it is now estimated that viruses are detected during half of all COPD exacerbations and are associated with poorer clinical outcomes. Human rhinovirus, respiratory syncytial virus and influenza are the most commonly detected viruses during exacerbation. The role of persistent viral infection (adenovirus) has also been postulated as a potential pathogenic mechanism in COPD. Viral pathogens may play an important role in driving COPD progression by acting as triggers for exacerbation and subsequent lung function decline whilst the role of chronic viral infection remains a plausible hypothesis that requires further evaluation. There are currently no effective antiviral strategies for patients with COPD. Herein, we focus on the current understanding of the cellular and molecular mechanisms of respiratory viral infection in COPD.

Respiratory syncytial virus-associated illness in adults with advanced chronic obstructive pulmonary disease and/or congestive heart failure

BACKGROUND

Respiratory syncytial virus (RSV) is recognized as a serious pathogen in people with chronic cardiopulmonary conditions. Immunoprophylaxis might be considered for adults at high-risk for frequent and severe RSV infection. Thus, we studied the incidence of RSV-related medically attended acute respiratory illness (MARI) in adults with severe chronic obstructive pulmonary disease (COPD) and/or congestive heart failure (CHF).

METHODS

Subjects ≥50 years of age with Gold Class III/IV COPD and/or American Heart Association class III/IV CHF and exposure to children ≥once per month were recruited. Subjects were evaluated over 1.5 to 2.5 years for RSV-associated MARI, defined as polymerase chain reaction (PCR) and/or seroresponse.

RESULTS

Four hundred forty-five subjects were enrolled between October 2011 and May 2012. Overall, 99 RSV infections were documented by PCR or serology for a cumulative incidence of 22.2%. Of these, 42 (9.4%) subjects had protocol-specified RSV-MARI for an incidence of 4.68/100 patient-seasons. All-cause MARI was common (63.85/100 patient-seasons) with rhinovirus most commonly identified.

CONCLUSION

RSV infection was common in adults with severe COPD and/or advanced CHF. Given the severity of underlying cardiopulmonary diseases in the study population, most illnesses were surprisingly mild. Thus, active immunization rather than passive immunoprophylaxis with monoclonal antibodies may be a more cost-effective strategy.

Preclinical Characterization of PC786, an Inhaled Small-Molecule Respiratory Syncytial Virus L Protein Polymerase Inhibitor

Although respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infection in infants and young children, attempts to develop an effective therapy have so far proved unsuccessful. Here we report the preclinical profiles of PC786, a potent nonnucleoside RSV L protein polymerase inhibitor, designed for inhalation treatment of RSV infection. PC786 demonstrated a potent and selective antiviral activity against laboratory-adapted or clinical isolates of RSV-A (50% inhibitory concentration [IC₅₀], <0.09 to 0.71 nM) and RSV-B (IC₅₀, 1.3 to 50.6 nM), which were determined by inhibition of cytopathic effects in HEp-2 cells without causing detectable cytotoxicity. The underlying inhibition of virus replication was confirmed by PCR analysis. The effects of PC786 were largely unaffected by the multiplicity of infection (MOI) and were retained in the face of established RSV replication in a time-of-addition study. Persistent anti-RSV effects of PC786 were also demonstrated in human bronchial epithelial cells. In vivo intranasal once daily dosing with PC786 was able to reduce the virus load to undetectable levels in lung homogenates from RSV-infected mice and cotton rats. Treatment with escalating concentrations identified a dominant mutation in the L protein (Y1631H) in vitro. In addition, PC786 potently inhibited RSV RNA-dependent RNA polymerase (RdRp) activity in a cell-free enzyme assay and minigenome assay in HEp-2 cells (IC₅₀, 2.1 and 0.5 nM, respectively). Thus, PC786 was shown to be a potent anti-RSV agent via inhibition of RdRp activity, making topical treatment with this compound a novel potential therapy for the treatment of human RSV infections.

The epidemiology of medically attended respiratory syncytial virus in older adults in the United States: A systematic review

Objective

This review was undertaken to assess the historical evidence of the disease incidence and burden of laboratory-confirmed respiratory syncytial virus (RSV) in medically attended older adults.

Design

A qualitative systematic literature review was performed; no statistical synthesis of the data was planned, in anticipation of expected heterogeneity across studies in this population.

Methods

A literature search of PubMed, Embase, and the Cochrane Library was conducted for studies of medically attended RSV in older adults (≥ 50 years) published in the last 15 years. Two independent reviewers screened titles and abstracts based on predefined inclusion and exclusion criteria.

Results

From 10 studies reporting incidence proportions, RSV may be the causative agent in up to 12% of medically attended acute respiratory illness in older adults unselected for comorbidities, with variations in clinical setting and by year. In multiple studies, medically attended–RSV incidence among older adults not selected for having underlying health conditions increased with increasing age. Of prospectively followed lung transplant recipients, 16% tested positive for RSV. In hospitalized adults with chronic cardiopulmonary diseases, 8% to 13% were infected with RSV during winter seasons (8%-13%) or metapneumovirus season (8%). Hospitalizations for RSV in older adults typically lasted 3 to 6 days, with substantial proportions requiring intensive care unit admission and mechanical ventilation. Among older adults hospitalized with RSV, the mortality rate was 6% to 8%.

Conclusions

Protection of older adults against RSV could reduce respiratory-related burden, especially as age increases and the prevalence of comorbidities (especially cardiopulmonary comorbidities) grows.

Clinical characteristics and outcome of respiratory syncytial virus infection among adults hospitalized with influenza-like illness in France

OBJECTIVES

The aim of this study was to analyse characteristics and outcome of respiratory syncytial virus (RSV) infection in adults hospitalized with influenza-like illness (ILI).

METHODS

Patients hospitalized with ILI were included in this prospective, multicentre study carried out in six French hospitals during three consecutive influenza seasons (2012-2015). RSV and other respiratory viruses were detected by multiplex PCR in nasopharyngeal swabs. Risk factors for RSV infection were identified by backward stepwise logistic regression analysis.

RESULTS

A total of 1452 patients hospitalized with ILI were included, of whom 59% (861/1452) were >65 years and 83% (1211/1452) had underlying chronic illnesses. RSV was detected in 4% (59/1452), and influenza virus in 39% (566/1452). Risk factors for RSV infection were cancer (adjusted OR 2.1, 95% CI 1.1-4.1, p 0.04), and immunosuppressive treatment (adjusted OR 2.0, 95% CI 1.1-3.8, p 0.03). Patients with RSV had a median length of stay of 9 days (6-25), and 57% of them (30/53) had complications, including pneumonia (23/53, 44%) and respiratory failure (15/53, 28%). Fifteen per cent (8/53) were admitted to an intensive care unit, and the in-hospital mortality rate was 8% (4/53). Pneumonia was more likely to occur in patients with RSV than in patients with RSV-negative ILI (44% (23/53) versus 26% (362/1393), p 0.006) or with influenza virus infection (44% versus 28% (157/560), p 0.02).

CONCLUSION

RSV is an infrequent cause of ILI during periods of influenza virus circulation but can cause severe complications in hospitalized adults. Risk factors for RSV detection in adults hospitalized with ILI include cancer and immunosuppressive treatment. Specific immunization and antiviral therapy might benefit patients at risk.

Respiratory syncytial virus infection in older adults: an under-recognized problem

Human respiratory syncytial virus (RSV) is an enveloped, single-stranded, negative-sense RNA virus and member of the Paramyxoviridae family of the genus Pneumovirus that was first reported as a major pathogen in pediatric populations. However, since its discovery, RSV has not infrequently been detected in adults. Reinfection occurs throughout life, with more severe disease occurring in older adults, immunocompromised patients, and those with underlying cardiopulmonary disease. Initially described as the cause of nursing home outbreaks of respiratory disease, there is a now significant body of literature describing the clinical importance of RSV in older adults in a multitude of settings including long-term care, adult daycares, and in community-dwelling adults. Moreover, recent reports from China and other countries emphasize that RSV is a global pathogen that will become increasingly important in developed nations with aging populations. Annual attack rates in the USA range from 2 to 10% in community-dwelling older adults and 5-10% in older adults living in congregate settings. Population-based calculations of the proportion of acute respiratory illnesses attributable to RSV estimate that 11,000 elderly persons die annually in the USA of illnesses related to RSV infection. Clinical manifestations of RSV infections are similar to that of other viral respiratory pathogens and include cough, nasal congestion, rhinorrhea, sore throat, and dyspnea. Lower respiratory tract disease is common and may result in respiratory failure (8-13%) or death (2-5%). Recent advances in molecular diagnostics have made it possible to rapidly identify RSV infection using nucleic acid amplification tests, although clinicians will need to suspect the diagnosis when viral activity is high. At the present time, treatment is supportive. Effective antiviral agents for the treatment and vaccines for prevention of RSV remain a significant unmet medical need in the older adult population.

Respiratory syncytial virus infection-associated hospitalization in adults: a retrospective cohort study

BACKGROUND

Once considered primarily a pediatric concern, respiratory syncytial virus (RSV) infection is gaining recognition as a cause of significant morbidity and mortality in adults. A better understanding of RSV epidemiology and disease in adults is needed to guide patient management and to assess the need for prophylaxis, vaccines, and treatments.

METHODS

We conducted a retrospective cohort study of adults admitted to four hospitals in Toronto, Canada, between September 2012 and June 2013 with RSV identified by a qualitative real-time reverse-transcriptase polymerase chain reaction assay in nasopharyngeal swab or bronchoscopy specimens. Main outcomes were hospital length of stay, need for intensive care unit (ICU) or mechanical ventilation, and all-cause mortality.

RESULTS

Eighty-six patients were identified as requiring hospitalization for RSV infection (56% female). Median age was 74 (range 19-102) years; 29 (34%) were < 65 years. Eighty-three (97%) had underlying chronic medical conditions; 27 (31%) were immunosuppressed, and 10 (12%) known smokers. The most common symptoms and signs were cough in 73 (85%), shortness of breath in 68 (79%), sputum production in 54 (63%), weakness in 43 (50%), fever in 41 (48%), and wheezing in 33 (38%). Lower respiratory tract complications occurred in 45 (52%), cardiovascular complications occurred in 19 (22%), and possible co-pathogens were identified in 11 (13%). Sixty-seven (78%) were treated with antibiotics and 31 (36%) with anti-influenza therapy. Thirteen (15%) required ICU care and 8 (9%) required mechanical ventilation. Five (6%) died during hospitalization. Need for ICU and mechanical ventilation were associated with mortality (P ≤ 0.02). Median hospital length of stay was 6 days (mean 10.8 days).

CONCLUSIONS

RSV infection is associated with the need for extended hospital stay, ICU care and mortality in adults of all ages with chronic underlying conditions. Presenting signs and symptoms are nonspecific, co-infections occur, and patients often receive antibiotics and anti-influenza therapy. There is need for ongoing research and development of RSV prophylaxis, vaccines and treatments for adults.