Neighborhood-Level Burden of Social Risk Factors on Respiratory Syncytial Virus Hospitalization in Ontario, Canada, 2016-2019.

Background: Beyond clinical risk factors, little is known about the impact of social determinants on respiratory syncytial virus (RSV) burden. Our study aimed to estimate RSV-related hospitalization rates across sociodemographic and housing characteristics. Methods: We conducted a population-based study of all RSV-related hospitalizations in Ontario, Canada, between September 1, 2016, and August 31, 2019, using validated hospital discharge codes and census data. Crude and age-standardized annualized RSV incidence rates and rate ratios (RRs) were estimated for a range of individual-level demographics and neighborhood-level measures of marginalization and housing characteristics. Results: Overall, the annual RSV-related hospitalization rate was 27 per 100 000, with the highest rates observed in children age <12 months (1049 per 100 000) and 12-23 months (294 per 100 000) and adults age ≥85 years (155 per 100 000). Higher RSV-related hospitalization rates were associated with increasing marginalization quintile (Q) of material resources (RR, 1.4; Q5: 33 per 100 000 vs Q1: 24 per 100 000) and household instability (RR, 1.5; Q5: 31 per 100 000 vs Q1: 22 per 100 000). Conclusions: The burden of RSV-related hospitalization was greatest in young children and older adults, with variation by sociodemographic and housing factors. Understanding the role of these social factors is crucial for informing equitable preventive program delivery.

Economic burden of respiratory syncytial virus in adults in Germany - a health claims analysis between 2015 and 2018.

AIMS: Respiratory syncytial virus (RSV) causes severe lower respiratory tract infections (LRTI) in infants and adults. While the clinical burden was recently estimated in adults in Germany, little is known about the economic burden yet. To fill this gap, we aimed to assess hospital and outpatient healthcare resource utilization (HRU) and costs of RSV infections in adults in Germany. METHODS: In this retrospective, observational study on nationwide, representative, anonymized claims data (2015-2018), we identified patients ≥18 years with ICD-10-GM-codes specific to RSV ('RSV-specific'). To increase sensitivity, patients with unspecified LRTIs (including unspecified bronchitis, bronchiolitis, bronchopneumonia, and pneumonia) during RSV seasons were also included as cases potentially caused by RSV ('RSV-possible'). RSV-related HRU (hospital days, ICU and ventilation treatment, drug dispensation) and direct costs were estimated per episode. Excess costs per episode and for follow-up periods were compared to a matched control cohort. All outcomes were reported per healthcare sector and stratified by age and risk groups as well as disease severity (ICU admission/ventilation). RESULTS: Direct inpatient and outpatient mean episode costs were 3,473€and 82€, respectively, with substantially higher costs for severe cases requiring intensive care and/or ventilation (10,801€). Direct costs for RSV-specific cases were higher than for RSV-possible cases (inpatients: 6,247€vs. 3,450€; outpatients: 127€vs. 82€). Moreover, costs were significantly higher for RSV patients than for controls and increased over time (inpatients: 5,140€per episode vs 10,093€per year; outpatients: 46€per quarter vs 114€per year). LIMITATIONS: While the number of RSV-specific cases was low, inclusion of seasonal LRTI cases likely increased the sensitivity to detect RSV cases and allowed a better estimation total costs of RSV. CONCLUSIONS: The economic burden of RSV-LRTI in adults in Germany is substantial, persists long-term and is particularly high in the elderly. This highlights the need for cost-effective prevention measures.

Noninferior Immunogenicity and Consistent Safety of Respiratory Syncytial Virus Prefusion F Protein Vaccine in Adults 50-59 Years Compared to ≥60 Years of Age.

BACKGROUND: The adjuvanted respiratory syncytial virus (RSV) prefusion F protein-based vaccine (RSVPreF3 OA) is approved in adults aged ≥60 years. We evaluated RSVPreF3 OA immunogenicity and safety in adults aged 50-59 years without or with increased risk for RSV disease due to specific chronic medical conditions. METHODS: This observer-blind, phase 3, noninferiority trial included adults aged 50-59 years, stratified into 2 subcohorts: those with and those without predefined, stable, chronic medical conditions leading to an increased risk for RSV disease. Participants in both subcohorts were randomized 2:1 to receive RSVPreF3 OA or placebo. A control group of adults aged ≥60 years received RSVPreF3 OA. Primary outcomes were RSV-A and RSV-B neutralization titers (geometric mean titer ratios and sero-response rate differences) 1 month post-vaccination in 50-59-year-olds versus ≥60-year-olds. Cell-mediated immunity and safety were also assessed. RESULTS: The exposed population included 1152 participants aged 50-59 years and 381 participants aged ≥60 years. RSVPreF3 OA was immunologically noninferior in 50-59-year-olds versus ≥60-year-olds; noninferiority criteria were met for RSV-A and RSV-B neutralization titers in those with and those without increased risk for RSV disease. Frequencies of RSVPreF3-specific polyfunctional CD4+ T cells increased substantially from pre- to 1 month post-vaccination. Most solicited adverse events had mild-to-moderate intensity and were transient. Unsolicited and serious adverse event rates were similar in all groups. CONCLUSIONS: RSVPreF3 OA was immunologically noninferior in 50-59-year-olds compared to ≥60-year-olds, in whom efficacy was previously demonstrated. The safety profile in 50-59-year-olds was consistent with that in ≥60-year-olds. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov: NCT05590403.

Disease Burden of RSV Infections and Bronchiolitis in Young Children (< 5 Years) in Primary Care and Emergency Departments: A Systematic Literature Review.

Respiratory syncytial virus (RSV) is the most common cause of acute respiratory infections in young children. Limited data are available on RSV disease burden in primary care and emergency departments (EDs). This review synthesizes the evidence on population-based incidence rates of RSV infections in young children (< 5 years) in primary care and EDs. A systematic literature review was performed in PubMed and Embase. Studies reporting yearly population-based RSV incidence rates in primary care and EDs were included. A total of 4244 records were screened and 32 studies were included, conducted between 1993 and 2019. Studies were mainly performed in high-income countries (n = 27), with 15 studies in North America and 10 studies in Europe. There was significant variability in study methodology and setting among studies, resulting in considerable variability in reported incidence rates. Incidence rates were higher in primary care-ranging from 0.8 to 330 (median = 109) per 1000 population-compared to EDs (7.5-144.0, median = 48). The highest incidence rates were reported in infants. Additionally, incidence rates were higher in high-income countries and in studies using laboratory-confirmed RSV cases compared to studies using bronchiolitis ICD-codes (non-laboratory confirmed). Our study found that a substantial number of children under 5 years of age attend primary care settings and EDs, every year for RSV infections. Due to the considerable heterogeneity in study methodology, it was impossible to draw definitive conclusions regarding factors explaining differences in reported incidence rates. Additionally, more studies in low- and middle-income countries are recommended.

Hospital surveillance of respiratory viruses during the COVID-19 pandemic and beyond: contribution to the WHO mosaic framework, Israel, 2020 to 2023.

BackgroundA new respiratory virus surveillance platform, based on nationwide hospital laboratory data, was established in Israel during the COVID-19 pandemic.AimWe aimed to evaluate the performance of this platform with respect to the detection of influenza and respiratory syncytial virus (RSV) from week 36 in 2020 to week 15 in 2023, and how it fits with the World Health Organization (WHO) mosaic surveillance framework.MethodsData of respiratory samples from hospitalised patients sent for laboratory confirmation of influenza virus or RSV from 25 general hospital laboratories nationwide were collected. We analysed the weekly number and percentage of samples positive for influenza virus or RSV vis-à-vis SARS-CoV-2 activity and compared data from the new surveillance platform with existing surveillance platforms. Using data in the new surveillance platform, we analysed early stages of a 2021 out-of-season RSV outbreak and evaluated the capabilities of the new surveillance system with respect to objectives and domains of the WHO mosaic framework.ResultsThe new hospital-laboratory surveillance platform captured the activity of influenza virus and RSV, provided crucial data when outpatient sentinel surveillance was not operational and supported an out-of-season RSV outbreak investigation. The new surveillance platform fulfilled important objectives in all three domains of the mosaic framework and could serve for gathering additional information to fulfil more domain objectives.ConclusionThe new hospital laboratory surveillance platform provided essential data during the COVID-19 pandemic and beyond, fulfilled important domain objectives of the mosaic framework and could be adapted for the surveillance of other viruses.

Assessment of Knowledge, Attitudes, and Vaccination Practices Regarding the New RSV Vaccine among Health Professionals in Greece.

The introduction of a new vaccine into immunization programs represents a significant advancement in the global effort to combat vaccine-preventable diseases. Data from the World Health Organization support that immunization prevents between 2 and 3 million deaths each year across various diseases, underscoring its pivotal role in global health. The present study aims to assess the knowledge, attitudes, and anticipated vaccination practices among health professionals in Central Greece in response to the potential introduction of new Respiratory Syncytial Virus (RSV) vaccination guidelines by the National Vaccines Committee. Among the 450 health professionals solicited for the study, 219 provided responses, yielding a response rate of approximately 55%. A substantial majority (70.3%) accurately identified the vaccine's current availability, and 62.1% were aware of the current recommendation for RSV vaccination in pregnant women. In response to whether health professionals support the inclusion of an RSV vaccine in the national vaccination program if it becomes commercially available and is recommended by the Greek National Immunization Program, general practitioners showed the most support, with an average score of 4.86 (95% CI, 4.69-5.00), followed by pediatricians at 4.76 (95% CI, 4.63-4.89), pulmonologists at 4.68 (95% CI, 4.36-5.00), and obstetricians at 4.33 (95% CI, 3.95-4.71). Concerning general opinions on vaccinations, a high level of agreement was noted among the majority of health professionals, excluding nurses. Pharmacists recorded the highest agreement, with a perfect score of 5 (CI, 5.00-5.00), followed closely by pediatricians at 4.99 (CI, 4.97-5.00), GPs at 4.95 (CI, 4.85-5.00), pulmonologists at 4.93 (CI, 4.83-5.00), obstetricians at 4.74 (CI, 4.42-5.00), and nurses at 3.80 (CI, 3.06-4.54). A tailored approach to education is needed to ensure that healthcare professionals can communicate more effectively about RSV risks and vaccination benefits, fostering a proactive stance towards disease prevention and patient care. In essence, our study underscores the importance of knowledge in shaping a compassionate and responsive healthcare environment, ready to meet the challenges of RSV head-on.

A 62-Year-Old Woman With Cough, Dyspnea, and Diffuse Lung Nodules.

CASE PRESENTATION: A 62-year-old woman came to our hospital with worsening cough and dyspnea over the preceding week, during which time she had been treated with azithromycin and prednisone for suspected pneumonia. She had no fever, chills, or sweats, but her cough had become productive of clear to blood-tinged phlegm during the interval. Medical history was significant for insulin-dependent diabetes mellitus and OSA. She had quit smoking 44 years earlier and had no history of lung disease. She was a bank teller residing in southeastern Minnesota and described no relevant inhalational or environmental exposures, drug use, aspiration, or travels preceding her illness.

Risk factors for severe disease in pediatric respiratory syncytial virus infections.

OBJECTIVES: To assess factors associated with the risk of severe disease in children aged 5 years or younger with laboratory-confirmed respiratory syncytial virus (RSV) infection. STUDY DESIGN: We conducted a nationwide retrospective cohort study in Mexico. METHODS: Eligible participants included children aged 5 years or younger with laboratory-confirmed RSV infection January 1, 2023, and May 15, 2024. We collected relevant clinical and epidemiological data. Risk ratios (RR) and 95% confidence intervals (CI) were employed to identify factors associated with the risk of severe disease, characterized by clinical and radiographic evidence of bronchiolitis or pneumonia requiring hospital admission. RESULTS: Data from 2022 children were analyzed and the overall risk of severe disease was 21.0% (n = 424/2022). In multiple generalized linear regression analysis, a personal history of immunosuppression (due to any cause) showed a protective effect (RR = 0.14, 95% CI 0.05-0.42, P = 0.001) against severe RSV disease, while an increased risk was documented for each additional day elapsed between the date of symptom onset and the date of seeking healthcare RR = 1.06, 95% CI 1.02-1.10, P = 0.004). CONCLUSION: These findings provide insights into risk stratification and suggest specific directions for future research. This information informs the development of targeted intervention strategies to mitigate the impact of RSV infections in this vulnerable population.

Clinical Performance of the BD Respiratory Viral Panel for BD MAX™ System in Detecting SARS-CoV-2, Influenza A and B, and Respiratory Syncytial Virus.

Using a nasopharyngeal (NP) or anterior nasal (NS) swab from prospectively collected or retrospective specimens, we assessed the clinical performance of the BD Respiratory Viral Panel (BD RVP) for BD MAX System against FDA-cleared or authorized comparators. Across prospective and retrospective specimens, positive percent agreement (PPA) was ≥ 98.4% for SARS-CoV-2, ≥ 96.7% for influenza (flu) A, ≥ 91.7% for respiratory syncytial virus (RSV), and 100% for flu B (retrospective only) while negative percent agreement (NPA) was ≥ 97.7% across all targets, leading to the assay FDA clearance. A head-to-head comparison of NS versus NP results with BD RVP was also performed; PPA was ≥ 90% and NPA ≥ 98.2% for SARS-CoV-2, flu A and RSV. These findings confirm that the BD MAX RVP assay performs well for detection and differentiation of the three viruses in NP and NS specimens, with strong interrater agreements for NS versus NP comparisons.

Nirsevimab: Alleviating the burden of RSV morbidity in young children.

Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infections (LRTIs) and hospital admissions in early childhood. Recent advancements in novel preventive therapies, including extended half-life monoclonal antibodies and antenatal vaccination, have afforded new opportunities to significantly reduce the burden of this infection. Nirsevimab is a novel monoclonal antibody that provides sustained protection against RSV for at least 5 months among newborns and young children. It has received regulatory approval in numerous countries and is being implemented across various settings. Two pivotal Phase 3 trials (MELODY, HARMONIE) demonstrated significant reductions in RSV-associated LRTI hospitalisations following nirsevimab administration, with treatment efficacy of 62.1% and 83.2%. Emerging real-world data from early adopters of nirsevimab corroborates these findings. Studies from Spain, Luxembourg, France and the USA report effectiveness rates between 82% and 90% in preventing RSV-associated hospitalisations among infants entering their first RSV season. Current implementation strategies for nirsevimab have primarily focused on seasonal administration for all infants, aligned to local RSV seasons, and often include catch-up doses for those born before the season begins. Available cost-effectiveness analyses indicate that while nirsevimab offers significant potential public health benefits, its adoption must carefully consider economic factors such as treatment costs, implementation strategies tailored to local viral epidemiology, and logistics for vaccine delivery. Overall, nirsevimab presents a promising opportunity to alleviate the burden of severe RSV infections in young children. However, ongoing surveillance and refinements in implementation strategies are crucial to optimise its impact and ensure sustainability across diverse health-care settings.

Bovine respiratory syncytial virus enhances the attachment of Trueperella pyogenes to cells.

In cattle, bovine respiratory syncytial virus (BRSV) is associated with secondary bacterial infections; however, the mechanisms of the interaction between BRSV and bacteria are unclear. Trueperella pyogenes (T. pyogenes) causes pneumonia in cattle and is involved in secondary infections following viral infections. In this study, we evaluated the effect of BRSV infection on the adhesion of T. pyogenes to BRSV-infected cells. BRSV infection significantly enhanced the adhesion of T. pyogenes to cells in a multiplicity of infection- and time-dependent manner. The BRSV-mediated change in the adhesion of T. pyogenes was widely observed in various cell types and bacterial strains. The results from the gentamicin protection assay showed that BRSV infection did not affect the intracellular invasion ability of T. pyogenes. Furthermore, adhesion assays conducted using BRSV G protein-expressing cells and anti-BRSV G antibodies revealed that the increased adhesion of T. pyogenes to cells was mediated by the G protein of BRSV. In addition, immunofluorescence assay revealed the colocalization of BRSV G protein and T. pyogenes. Thus, BRSV infection can potentially lead to bovine respiratory disease complex by promoting the adhesion of T. pyogenes to the infected cells.

Epidemiology, Outcomes, and Trend Analysis of Hospitalized Infants With Respiratory Syncytial Virus (RSV) Bronchiolitis From 1997 to 2019.

Background  Most children with respiratory syncytial virus (RSV) infection have a self-limiting course that can be managed with supportive care, and hospitalization is uncommon. The objectives of this study were to evaluate the epidemiology, outcomes, associated comorbidities, and temporal trends in the prevalence of infants one to 24 months of age who required hospitalization for RSV infection in the United States of America from 1997 to 2019. Methods In this retrospective cross-sectional study, we utilized the Kids' Inpatient Database (KID) to investigate the prevalence and outcomes of RSV bronchiolitis within a large cohort of discharged patients from 1997 to 2019. We included children one to 24 months of age admitted with a diagnosis of RSV bronchiolitis. Neonates were excluded from the analysis. A chi-square for linear trend was used to analyze trends in the prevalence of RSV bronchiolitis hospitalization, the presence of complex chronic conditions (CCC), congenital heart disease (CHD), the use of non-invasive and invasive mechanical ventilation (NIV and IMV), and hospital mortality. Results There were a total of 566,786 infants aged one to 24 months hospitalized with RSV infection out of a total of 9,309,597 discharges during the eight-year cohort, with a hospital prevalence of 60.9 per 1000 discharges and a hospital mortality rate of 0.09% (95% confidence interval (CI): 0.08%-0.1%). There was no trend in hospitalization rates of RSV infections per 100,000 U.S. population during the study period, with a decrease in hospital mortality trend. Children with RSV bronchiolitis were more likely to have government insurance and reside in zip codes with the lowest income quartile. There was a significant seasonal and regional variation in RSV-related hospitalizations. The presence of CCC was identified in 2.4% of the RSV group compared to 5.1% of non-RSV discharges (odds ratio (OR): 0.46, 95% CI: 0.45-0.47; p<0.001). The prevalence of RSV among all discharges has significantly increased over the study period, rising from 51.6 cases per 1000 discharges in 1997 to 180.1 cases per 1000 discharges in 2019 (p<0.001). The prevalence of CCC and CHD among RSV patients has also shown an upward trend, with CCC cases increasing from 1,411 in 1997 to 2,795 in 2019 and CHD cases rising from 1,795 to 3,622 during the same period. The use of invasive mechanical ventilation, non-invasive ventilation, and extracorporeal membrane oxygenation has consistently increased over time. Additionally, complications such as the need for cardiopulmonary resuscitation have demonstrated a similar increasing trend, although they have remained overall low. However, population-based hospitalization rates showed no significant trend. Conclusions The hospitalization rates at a population level in the United States for RSV infection in children aged one to 24 months remained steady from 1997 to 2019, while hospital mortality rates showed a declining trend. There is an increased proportion of comorbid conditions and increased resource utilization in children with RSV. These findings are important for monitoring the effectiveness of preventive strategies for severe RSV infections.

Implementation of the first respiratory syncytial (RSV) immunization campaign with nirsevimab in an autonomous community in Spain.

Respiratory syncytial virus (RSV) is the main cause of low respiratory tract infections in infants under one year of age. In the 2023/2024 season, the monoclonal antibody nirsevimab was available to protect children from RSV, and Spain has become one of the first countries worldwide to implement this strategy. It is essential to evaluate the results of this first campaign and different characteristics of the immunized population in order to plan next campaigns, especially for countries that are going to include this immunization. Our coverage was high (91.5% for those born during the season and 88.3% globally). For those born during the season, only 4.9% preferred not to immunize at the maternity hospital, which meant an average delay of 27.45 days. We observed a lower coverage in the population of immigrant origin. There was a rapid pace of immunization, since for those born before the beginning of the campaign the mean to be immunized was 15.63 days, without differences between healthy and at-risk children. This allows immunization before the RSV season (90% of the catch-up children had been immunized on November 3). The average age at which all the immunized children have received nirsevimab was lower in healthy children compared to those with risk conditions (49.65 versus 232.85 days). For those born during the campaign, the average age was also lower in healthy children (3.14 versus 14.58 days). In conclusion, we consider that the implementation of the immunization strategy with nirsevimab in the Region of Murcia, Spain, has been a success.

Maternal Immunization Decision-Making Among Pregnant and Lactating People in Kenya: A Qualitative Exploration of Peer Influences on Vaccine Decision-Making for a Future RSV Vaccine.

INTRODUCTION: Respiratory syncytial virus (RSV) is a leading cause of respiratory illness in infants globally, with new maternal RSV vaccines on the horizon. Vaccine decision-making during pregnancy is shaped by individual, interpersonal, community, and societal factors. This study explored key interpersonal influences on maternal vaccine decision-making among pregnant and lactating people (PLP) and community members in Kenya. METHODS: This qualitative study conducted in-depth interviews with six pregnant people, 18 lactating people, and 10 community members in one rural and one urban county in Kenya. Data were analyzed using a grounded theory approach. RESULTS: Participants identified the pregnant person themself, male partners, other family members, peers, and healthcare providers (HCPs) as key influences on the maternal immunization decision-making process. The majority of interviewed PLP believed that decision-making during pregnancy should be left to themselves due to autonomy and their role as the primary caregiver. Community members, including male partners, also identified pregnant people as the key decision-maker. While some PLP said they deferred to male partners to make vaccine decisions, more felt that men were not as informed on maternal and child issues as themselves or other female peers and relatives. HCPs emerged as important influences and information sources for PLP during decision-making. DISCUSSION: Understanding who influences vaccine-decision making during pregnancy will help inform demand generation strategies, and in turn, uptake of future maternal vaccines, including RSV vaccines. Given the strong role HCPs and peers have in the decision-making process, targeting key potential influences is essential to improve vaccine acceptance.

Epidemiology and viral loads of respiratory syncytial virus in hospitalized children prior to and during COVID-19 pandemic in Hangzhou, China.

Non-pharmaceutical interventions (NPIs) implemented to control SARS-CoV-2 have significantly influenced the activity of respiratory pathogens. This study investigated epidemiological changes among hospitalized patients with respiratory syncytial virus (RSV) before (2017-2019) and during (2020-2022) the COVID-19 pandemic in Hangzhou, China. We also examined viral load distribution across demographic and temporal variables. Nasopharyngeal swabs were collected and RSV loads were quantified using reverse transcriptase polymerase chain reaction (RT-qPCR). RSV epidemic characteristics, seasonal dynamics, and viral load distributions were compared between pre- and pandemic years. General linear models were employed to assess associations between viral loads and age. Among 19 742 cases, 1576 and 2092 tested positive during the pre- and pandemic years, respectively. From February to July 2020, the implementation of NPIs led to the cessation of RSV circulation. However, after these measures were relaxed, RSV cases resurged over two consecutive seasons during the pandemic, notably affecting older children compared to those in the pre-pandemic years (1.00 years, IQR: 0.50-2.00 vs. 0.58 years, IQR: 0.27-1.00, p < 0.001). Specifically, in 2021-2022, an off-season resurgence of RSV began earlier (mid-June), lasted longer (40 weeks), and involved more positive cases (1238 cases) than both 2020-2021 and pre-pandemic years. Viral load distribution demonstrated a clear age-related relationship in both pre- and pandemic years, with younger children consistently showing higher viral loads, independently of gender and season (all p-values for trends <0.001). These findings highlight the impact of NPIs on RSV epidemiology and underscore the need to prioritize RSV infection prevention in younger children from the perspective of viral load.

Respiratory syncytial virus immunization patterns in Germany, 2015-2020.

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection (LRTI) in infants and young children worldwide. Using routine statutory health insurance claims data including patients from all regions of Germany, we investigated the health-care resource use and costs associated with RSV prophylaxis with palivizumab in Germany. In the database, infants from the birth cohorts 2015-2019 eligible for palivizumab immunization were identified using codes of the 10th revision of the International Classification of Diseases (ICD-10). Health-care resource use and costs related to immunization were determined by inpatient and outpatient administrations. Over the study period, only 1.3% of infants received at least one dose of palivizumab in their first year of life. The mean number of doses per immunized infant was 4.6. From a third-party payer perspective, the mean costs of palivizumab per infant who received at least one dose in the first year of life was €5,435 in the birth cohorts 2015-2019. Despite the substantial risk of severe RSV infection, we found low rates of palivizumab utilization. Novel preventive interventions, featuring broader indications and single-dose administration per season, contribute to mitigating the burden of RSV disease across a more extensive infant population.

Immunogenicity, safety and reactogenicity of Ad26.RSV.preF/RSV preF protein vaccine in adults aged 60 to 75 years: A comparison of phase 2b and phase 3 clinical trial material.

The Ad26.RSV.preF/RSV preF protein vaccine has previously demonstrated efficacyin protecting older adults against respiratory syncytial virus (RSV)-related lower respiratory tract disease in a phase 2b study. This study compared the immunogenicity of vaccine clinical trial material (CTM) representative of phase 2b clinical studies with CTM used in phase 3 clinical studies. A total of 248 adults aged 60-75 years, randomized in a 1:1 ratio, received one dose of either phase 3 CTM or phase 2b CTM. Solicited adverse events (AEs), unsolicited AEs, and serious AEs (SAEs) were assessed for 7-d, 28-d, and 6-month periods post-vaccination, respectively. RSV preF-ELISA antibody titers and RSV neutralizing titers were measured before and 14 d after vaccination. The phase 3 CTM-induced preF-ELISA response at Day 15, in terms of geometric mean titer, was shown to be non-inferior to that induced by phase 2b CTM. The RSV neutralizing antibody titers were also similar in the two groups at Day 15. The safety profile in terms of solicited AEs, unsolicited AEs, or SAEs was in general similar between the phase 3 CTM and phase 2b CTM groups, and solicited AEs were mostly mild to moderate in intensity. No related SAEs were reported, and no safety concerns were identified.

Burden of respiratory syncytial virus infections in older adults with acute respiratory infection in Japan: An epidemiological study among outpatients.

BACKGROUND: Respiratory syncytial virus (RSV) is a leading cause of acute respiratory illness, with severe outcomes in older adults. Information on the prevalence, hospitalization rate, and impact on the health-related quality of life (HRQoL) of RSV in older adults with acute respiratory infections (ARI) in outpatient settings in Japan is limited. METHODS: This multi-center epidemiological study included outpatients aged ≥60 years presenting with ARI between August 2021 and February 2023. Nasal and throat swabs were collected and tested by reverse transcription polymerase chain reaction (RT-PCR). The prevalence of RT-PCR-confirmed RSV (cRSV)-ARI, cRSV-lower respiratory tract disease (LRTD), and other respiratory viruses was calculated by season, region, age group, and RSV subtype. HRQoL was assessed via patient-reported outcomes. RESULTS: The study included 923 ARI episodes (cRSV-ARI: N = 24; non-cRSV-ARI: N = 899). In years 1 and 2 (August 2021-July 2022 and August 2022-February 2023), the prevalence of cRSV-ARI was 2.5% and 2.8%, respectively. There was a predominance of RSV-B and RSV-A subtypes in years 1 and 2, respectively. In years 1 and 2 combined, 37.5% of cRSV-ARI cases had lower respiratory tract infection; all cRSV-LRTD cases occurred in those aged 60-74 years. RSV-ARI cases reported throat, chest, and respiratory symptoms, leading to impaired functioning and HRQoL. CONCLUSIONS: During the observed study period, RSV was circulating among older adults in Japan. RSV was a leading cause of ARI and LRTD. More data are needed to fully clarify the burden of RSV among older adults in Japan.