Search Results (360)

Background: Respiratory syncytial virus (RSV) infection is a cause of respiratory morbidity in high-risk patients, including those with chronic lung disease (CLD) and those undergoing hemodialysis (HD). In HD patients, evidence on the clinical impact of RSV vaccination on respiratory complications remains limited. We aimed to assess the clinical impact of RSV vaccination in HD patients by comparing vaccinated and unvaccinated patients with a focus on CLD. Methods: We retrospectively evaluated 56 adult HD patients: 28 received the RSV vaccine in autumn 2024 and 28 did not. Clinical data were collected from electronic medical records. Outcomes included influenza-like illness (ILI), pneumonia, and respiratory infection requiring hospitalization between September 2024 and September 2025. Results: Patients had a mean age of 74.4 years and a median Charlson Comorbidity Index (CCI) of 10. The RSV-vaccinated group had a greater comorbidity burden than the unvaccinated group (CCI 11 IQR 10–12 vs. 9 IQR 8–11, p = 0.02) and a higher prevalence of CLD (46.4% vs. 25.0%, p = 0.09). During follow-up, 28 patients (50.0%) had at least one ILI episode, 23 (41.1%) developed pneumonia, and 15 (26.8%) were hospitalized for respiratory infection. The incidence of ILI was 46.4% in vaccinated patients and 53.6% in unvaccinated patients (p = 0.28), while the incidence of pneumonia was 39.3% and 42.9%, respectively (p = 0.78). Respiratory infection requiring hospitalization occurred in 14.3% of vaccinated patients and 39.3% of unvaccinated patients (p = 0.035). CLD was significantly associated with pneumonia (p = 0.001) and showed trends toward higher rates of ILI (p = 0.09) and hospitalization for respiratory infection (p = 0.1). Conclusions: In our exploratory study, RSV vaccination in HD patients was associated with fewer hospitalizations for respiratory infection, despite greater comorbidity in vaccinated patients. CLD was associated with a higher incidence of respiratory complications, particularly pneumonia. The retrospective design and small sample size do not allow definitive conclusions; future prospective studies with an adequate sample size are needed to confirm our results. Full article

The recurrent emergence of viral outbreaks, including SARS-CoV-2, influenza, Ebola, and respiratory syncytial virus (RSV), continues to expose critical limitations in conventional antiviral therapies, particularly in terms of targeting specificity, bioavailability, and resistance development. Nanotechnology has emerged as a transformative approach to overcome these challenges. This review provides a comprehensive and critical analysis of nanoparticle-based antiviral systems, including lipid-based, polymeric, inorganic, and hybrid nanocarriers, with a focus on their roles in enhancing drug delivery, targeting precision, and therapeutic efficacy. These platforms exert antiviral effects through multiple coordinated mechanisms, including inhibition of viral entry, suppression of replication, gene silencing, and modulation of host immune responses. The clinical success of lipid nanoparticle-based mRNA vaccines highlights the translational potential of nanotechnology, while emerging nanotherapeutic strategies demonstrate increasing versatility across diverse viral pathogens. However, key challenges—including safety, scalability, formulation stability, and regulatory constraints—continue to limit widespread clinical implementation. Overall, nanoparticle-mediated antiviral systems represent a multifunctional and adaptable platform capable of addressing the limitations of conventional therapies and enabling more effective, resilient, and precision-driven strategies for future pandemic preparedness. Full article

Background: Messenger RNA (mRNA) vaccines have emerged as a versatile platform beyond SARS-CoV-2, with expanding applications in infectious diseases and oncology. However, comprehensive evidence synthesis of non-SARS-CoV-2 mRNA vaccines remains limited. Methods: This systematic review followed PRISMA 2020 guidelines and was registered in PROSPERO (CRD420261323500). MEDLINE, Embase, Web of Science, Scopus, ClinicalTrials.gov, and WHO ICTRP were systematically searched for studies published between 1 January 2000 and 28 February 2026. Eligible studies included phase I–III clinical trials and in vivo preclinical studies evaluating non-SARS-CoV-2 mRNA vaccines. Two reviewers independently screened studies, extracted data, and assessed risk of bias using RoB 2, ROBINS-I, and SYRCLE tools. Findings were synthesized narratively because of substantial heterogeneity. Results: A total of 40 studies met the eligibility criteria and were included in the review, comprising 20 clinical studies and 20 preclinical studies. Advanced clinical programs targeted influenza and respiratory syncytial virus (RSV), with phase III trials displaying seroconversion rates above 70% with good safety profiles. Preliminary phase I studies for HIV, cytomegalovirus, rabies, and personalized cancer mRNA vaccines showed promising humoral and cellular immune responses. Preclinical studies showed strong antibody and T-cell responses against malaria, tuberculosis, Group B Streptococcus, and Zika virus. Most adverse events were mild to moderate, while serious vaccine-related adverse events were uncommon. Conclusions: Non-SARS-CoV-2 mRNA vaccines demonstrate substantial translational potential across infectious disease and oncology applications. Although the vaccine candidates have demonstrated promising immunogenicity and safety, most are in the early stages of development. This highlights the need for large trials, long-term safety follow-up and better global representation. Full article

Every year, respiratory syncytial virus (RSV) causes an estimated 33 million lower respiratory tract infections in children under five years of age, driving millions of hospitalizations worldwide and substantial mortality in developing countries. For 28 years, the monoclonal antibody (mAb) palivizumab has been the principal agent for RSV immunoprophylaxis, reducing hospitalization in defined high-risk groups through monthly intramuscular dosing. The recent approval of two second-generation long-acting mAbs, nirsevimab and clesrovimab, and maternal preF vaccine has fundamentally changed the RSV prevention landscape. In contrast to palivizumab, the long-acting mAbs offer single-dose seasonal protection across a broader infant population, enabling universal immunization programmes for the first time. In this review, we conjointly examine nirsevimab and clesrovimab across their mechanisms of action, pharmacokinetics, efficacy, safety and cost-effectiveness, using palivizumab as the reference standard. Cross-trial efficacy comparisons are complicated by differences in study populations and endpoint definitions; however, when these factors are considered, the available evidence suggests that all three agents offer broadly comparable protection against severe RSV disease. All three agents also demonstrate favourable and comparable tolerability profiles. Nirsevimab is now supported by a substantial body of real-world evidence confirming effectiveness in routine immunization programmes that closely align with registrational studies. Clesrovimab, as the newest agent, currently lacks real-world effectiveness, and both long-acting monoclonals require further confirmatory evidence in high-risk groups. Overall, existing data support that both monoclonals have equivalent efficacy and safety profiles as palivizumab, and choice should be based on cost-effectiveness and local availability, with consideration given to optimal integration of infant immunoprophylaxis alongside maternal RSV vaccination programmes. Full article

Mucosal immunity in the respiratory tract provides the first line of defense against airborne pathogens, yet most current vaccines fail to induce strong and durable immune responses at these sites. Respiratory viruses, including respiratory syncytial virus (RSV), influenza viruses, and coronaviruses, remain major global health threats, in part due to their ability to evade long-term mucosal protection. Although systemic vaccination generates robust circulating immunity, it induces limited local responses, particularly secretory immunoglobulin A (IgA), which is critical for preventing viral entry and transmission at the airway surface. The mechanisms regulating B cell responses within the airway mucosa are not fully understood. B cell–activating factor (BAFF), a member of the tumor necrosis factor (TNF) superfamily, has emerged as an important context-dependent regulator of mucosal B cell immunity. BAFF is produced by airway epithelial cells and multiple myeloid populations, including dendritic cells and neutrophils, and is rapidly induced during respiratory viral infection through type I interferon–dependent pathways. Functionally, BAFF supports B cell survival, differentiation, and class-switch recombination, promoting the generation of antibody-secreting plasma cells and enhancing IgA production. In the lung, these effects align with early, intermediate, and late stages of the response, supporting initial local antibody production, the formation of inducible bronchus-associated lymphoid tissue (iBALT), and the development of tissue-resident memory B cells that sustain long-term immunity. Although BAFF plays an essential role in mucosal immunity, its activity requires tight regulation to maintain immune balance. Current evidence supports BAFF as a promising immunomodulatory component and highlights its potential as an adjuvant platform for enhancing mucosal vaccine efficacy, warranting further investigation as a potential adjuvant in this context. Full article

Objectives: This study aims to assess the acceptance of vaccinations among pregnant women, particularly against influenza, pertussis, COVID-19, and RSV, and to identify factors influencing their willingness to get vaccinated. It also seeks to evaluate the impact of the COVID-19 pandemic on maternal attitudes and behaviors regarding vaccination. Methods: The analysis involved a review of existing literature and studies to evaluate the level of vaccine acceptance among pregnant women before and after the COVID-19 pandemic. Factors contributing to vaccine hesitancy, including misinformation, lack of knowledge, and the influence of healthcare professionals, were examined. Results: The findings indicated that, despite scientific evidence supporting the safety and efficacy of vaccines during pregnancy, public concerns remain about their impact on the developing fetus. The outbreak of the COVID-19 pandemic has increased awareness of the risk of infectious diseases, but at the same time, its impact on vaccination rates among pregnant women is ambiguous and geographically diverse. Misinformation and decreased access to healthcare during the pandemic negatively affected vaccine uptake. Trustworthy information provided by healthcare professionals emerged as a key factor in promoting vaccine acceptance. Conclusions: To improve vaccination rates among pregnant women, it is essential to provide clear, evidence-based information through healthcare professionals, particularly those directly caring for pregnant women. Educational campaigns should address concerns calmly and without judgment, emphasizing the safety and benefits of vaccinations. Enhanced access to healthcare and vaccinations, along with strategic information dissemination, can significantly improve vaccine acceptance during pregnancy. Lessons learned from past pandemics should be incorporated into the development of healthcare strategies aimed at implementing recommended vaccinations for pregnant women in the future. Full article

Background/Objectives: Respiratory syncytial virus (RSV) is a major cause of respiratory illness across the lifespan, yet its health-economic burden in adults remains under-recognized. Building on a previously published nationwide analysis of RSV-associated hospitalizations in Switzerland (2017–2023), this study aimed to estimate age-specific direct inpatient hospitalization costs and assess their implications for healthcare systems. Methods: We conducted a nationwide health-economic analysis using Swiss Federal Statistical Office (FSO) hospitalization data (2017–2023) combined with SwissDRG-based cost statistics (2024). Age-specific costs per hospitalization were applied to RSV-associated hospitalization counts. To account for disease severity, additional estimates were derived by applying RSV-specific length-of-stay (LOS) ratios between RSV-associated and all-cause hospitalizations, reflecting the longer duration of RSV-associated admissions. Results: Total RSV-associated hospitalization costs were estimated at CHF 55.1–76.0 million annually. Children aged 0–9 years accounted for the highest number of hospitalizations and the largest share of total costs (CHF 27.8–34.3 million). Despite fewer hospitalizations, adults aged ≥60 years generated comparable total costs (CHF 23.6–36.7 million), driven by substantially higher costs per case. Costs increased markedly with age, reflecting longer hospital stays and higher clinical severity. Additional analyses demonstrated a substantial increase in costs in the post-pandemic period, particularly in older adults, suggesting improved detection of RSV-associated hospitalizations. Conclusions: RSV-associated hospitalizations impose a substantial economic burden on the Swiss healthcare system. The disproportionate contribution of older adults highlights the importance of targeted prevention strategies and provides a foundation for future health-economic evaluations and policy decision-making. Full article

Respiratory syncytial virus (RSV) is considered the leading causative agent of acute lower respiratory infections in infants and young children worldwide, which makes it a major contributor to pediatric morbidity and mortality. Infants are especially susceptible to severe disease in early life, which underlines the urgent need for developing effective immunization strategies against this virus. However, the development of vaccines against RSV has long been associated with significant challenges. For example, initial attempts, especially those involving formalin-inactivated RSV, resulted in vaccine-enhanced respiratory disease upon subsequent infection, which set a significant safety obstacle for future vaccine candidates. Other challenges facing vaccine development against RSV include the short-lived immunity induced by natural infection, lack of clear correlates of immunity, and immune naivety in infants. Recent breakthroughs in structural virology and immunology have provided insights into protective immunity against RSV, especially regarding neutralizing antibodies that recognize the virus in its prefusion conformation of the viral F protein. Among promising vaccine candidates, intranasal live-attenuated vaccines have emerged as especially promising for infant immunization, especially considering their close mimicry of natural infection that can elicit systemic as well as mucosal immunity in the respiratory tract. A newly emerging approach for live-attenuated virus vaccine development is codon-pair deoptimization (CPD), which is based on synthetic recoding that reduces viral replicative capacity while maintaining intact protein sequences and structure. The preclinical results of CPD-based RSV candidates have provided evidence of such vaccines’ ability to elicit robust immunity while maintaining favorable safety profiles. This review addresses the major challenges associated with the development of effective RSV vaccines for infant immunization, with particular emphasis on lessons learned from previous vaccine failures and recent advances in RSV vaccine development, particularly CPD-based attenuation strategies. Full article

Background: Self-compassion is the practice of treating oneself with kindness and understanding during times of hardship. There is a lack of studies investigating the associations between self-compassion and vaccination behaviors. This study investigated the associations between self-compassion and behavioral intention to receive seasonal influenza vaccination (SIV), pneumococcal vaccination (PV), and respiratory syncytial virus (RSV) vaccination among community-living older adults in Western China. Methods: A cross-sectional survey was conducted among people aged ≥60 years in Kashgar, China between January and February 2026. Participants were recruited through multi-stage random sampling. Multivariable logistic regression models were fitted. Results: Among all participants, 56.5% intended to receive a fully subsidized SIV in the next year. Among those without a prior vaccination history, 48.2% and 49.7% intended to receive fully subsidized PV and RSV vaccination in the next year, respectively. After adjusting for significant background characteristics, higher levels of self-compassion (e.g., higher levels of mindfulness, self-kindness and common humanity, and lower levels of over-identification, isolation and self-judgment) were associated with higher odds of behavioral intention to receive a fully subsidized SIV, PV and/or RSV vaccination. Conclusions: Our findings suggested a new angle to promote vaccination uptake. Future studies may evaluate the efficacy of self-compassion interventions in improving vaccination uptake among older adults. Full article

Background/Objectives: Respiratory syncytial virus (RSV), human metapneumovirus (hMPV), and parainfluenza virus type 3 (PIV3) are leading causes of acute respiratory infections in children and the elderly, yet no licensed T-cell vaccines are available. This study aimed to develop multivalent T-cell vaccine candidates against these pathogens using a live attenuated influenza virus (LAIV) vector platform. Methods: Conserved F, N, and M proteins of RSV, hMPV, and PIV3 were identified through multiple sequence alignments. Fragments enriched with experimentally confirmed and predicted T-cell epitopes were selected using the IEDB and NetMHCpan servers. These fragments were assembled into polyepitope immunogenic cassettes, and their selected order was determined by thermodynamic analysis of mRNA secondary structures using the RNAfold Web Server. The selected cassettes were cloned into the neuraminidase (NA) gene of a cold-adapted LAIV vector. Recombinant viruses were rescued by reverse genetics and assessed for replicative fitness in embryonated chicken eggs and MDCK cells, NA enzymatic activity and genetic stability upon serial passaging. Results: Four cassettes were designed for RSV, three for hMPV, and one for PIV3, all containing fragments with multiple T-cell epitopes. Three recombinant viruses of LAIV/RSV type and three of LAIV/hMPV type were successfully rescued, while attempts to recover the remaining recombinant viruses, i.e., LAIV/RSV and LAIV/PIV3, were not successful. All rescued recombinant viruses replicated to titers comparable to the parental LAIV strain and retained the full-length insert for at least eight passages in eggs. Importantly, NA enzymatic activity of the LAIV vector was not compromised by the insertion of the polyepitope T-cell cassettes. Conclusions: We developed a panel of recombinant T cell-based vaccine candidates against RSV and hMPV using the LAIV vector platform. These recombinant viruses encode conserved T-cell epitopes of the target viruses while retaining the biological properties of LAIV strains. Taken together, these characteristics warrant further evaluation of these recombinant viruses in appropriate relevant in vitro models to directly assess their immunogenicity in terms of stimulating a T-cell response against target pathogens. Full article

Background/Objectives: Respiratory syncytial virus (RSV) is the leading cause of infant hospitalizations in the United States. Prevention strategies are recommended to mitigate severe RSV outcomes. In addition to identifying potential coverage gaps, preventative administration timing is important for estimating product effectiveness. This study characterized administration timing of maternal and infant immunization against RSV across the United States during the 2024–2025 RSV season. Methods: A retrospective cross-sectional study was conducted using administrative claims of a commercially insured population from Kythera Labs. Pregnant individuals who received RSVpreF vaccine and infants who received nirsevimab were included. The seasonal cohort included infants born during the RSV season, while infants born from April to September were considered as the catch-up cohort. Baseline characteristics and calendar month and age at immunization (gestational age for RSVpreF) were evaluated. Results: Overall, 37,686 (71.9%) of maternal vaccinations were administered at 32–34 gestational weeks and 92.7% of all vaccinations occurred ≥14 days before delivery. Among infants who received nirsevimab, 34.8% of the seasonal cohort were immunized within 1 week of birth and 33.4% of the catch-up cohort were immunized in October 2024. Conclusions: Most maternal RSVpreF vaccinations occurred early in the recommended eligible gestational age window, while only approximately one-third of infants received nirsevimab during the first week of life or at the beginning of the RSV season. These findings highlight the importance of timely administration of RSV preventives. They further demonstrate that immunization timing should be incorporated into evaluation of the effectiveness and population level impact of RSV prevention programs. Full article

Background: Lower respiratory tract infections remain a major cause of morbidity and mortality in infants worldwide. Newborns possess an immature immune system but acquire passive immunity through maternal antibodies transferred via the placenta (IgG) and breast milk (IgA). Maternal vaccination may enhance this protection. This study aimed to quantify antibody levels against respiratory viruses in serum and breast milk from lactating women. Methods: Serum and breast milk samples were collected from 26 lactating mothers. Antibody levels were measured using an indirect enzyme-linked immunosorbent assay (ELISA) targeting seven viral antigens: influenza A (A/Thailand, A/California), influenza B (B/Phuket, B/Austria), SARS-CoV-2 (Spike and receptor-binding domain, RBD) and RSV F pre-fusion protein. Antibody isotypes IgG, IgA and IgM were analysed. Results: Virus-specific IgG and IgA antibodies were detected in all samples. Breast milk showed the highest levels of IgA, whereas serum contained higher IgG levels. A moderate positive correlation was observed between serum and milk IgG. No correlation was found between serum IgG and milk IgA, but both levels were elevated. Conclusions: Breast milk and serum contain relatively high levels of antibodies against the tested respiratory viruses. The elevated levels of serum IgG and milk IgA indicate a coordinated defence between systemic and mucosal immunity in response to infections. The levels and correlation of specific isotypes point to the source of the antibodies: milk IgG probably originates from the blood, whereas milk IgA is produced locally. Full article

Background/Objective: Respiratory syncytial virus (RSV) is an often under-recognized cause of respiratory illness in older adults. Clinical overlap with bacterial infections and delayed virologic confirmation may lead to the unnecessary prescription of antibiotics and antimicrobial resistance (AMR). This systematic review was conducted to assess antibiotic prescription in older adults with RSV and the factors influencing these decisions. Methods: This systematic review was preregistered in PROSPERO (CRD42024586905) and reported according to PRISMA guidelines. PubMed/MEDLINE, Embase, Web of Science, Cochrane CENTRAL, and Scopus were searched for studies published between January 2000 and August 2025. Eligible studies were those including adults aged ≥60 or ≥65 years with RSV infection and reporting antibiotic use. Data on antibiotic prescription, confirmed bacterial infection, hospitalization, length of stay (LOS), and prescribing indications were extracted. Results: Eight observational studies across inpatient, outpatient, emergency, and primary-care settings were included. Antibiotic prescribing ranged from 40.0% to 97.7%, whereas confirmed bacterial infection did not exceed 20% in any study. Antibiotic prescribing was associated with diagnostic uncertainty, radiologic findings, inflammatory markers, respiratory distress, delayed RSV testing, and multimorbidity rather than microbiological confirmation. Hospitalization rates varied across settings, and the LOS ranged from 3.5 to 11 days. None of the studies reported antibiotic discontinuation following RSV confirmation. Conclusions: Older adults with RSV frequently receive antibiotics despite low rates of confirmed bacterial infection, indicating substantial empirical prescribing. Improved rapid diagnostics, reassessment of therapy, and strengthened antimicrobial stewardship may help reduce unnecessary antibiotic use. RSV vaccination may be a promising strategy for reducing severe disease and hospitalization, with a potential indirect effect on antibiotic use, although these effects remain hypothetical. Full article

Respiratory syncytial virus (RSV) remains a leading cause of severe lower respiratory tract disease in infants, older adults, and immunocompromised individuals. Over the past decade, advances in structural biology, particularly cryo-electron microscopy (cryo-EM) and cryo-electron tomography (cryo-ET), have transformed our understanding of RSV architecture, dynamics, and the mechanisms of entry and replication. High-resolution structures of the prefusion F glycoprotein (pre-F) and its complexes with neutralizing antibodies established the rationale for structure-guided antigen stabilization and directly enabled the development of the first licensed RSV vaccines. Complementary structures of the ribonucleoprotein, polymerase complex, and matrix lattice have broadened therapeutic targets beyond F. Here, we summarize these structural advances; review current structure-guided vaccine, antibody, and antiviral development efforts; and highlight priorities for next-generation vaccines and therapeutics. Full article

The pseudovirus neutralization (PNT) assay is an established high-throughput, robust, and efficient BSL-2 method for detecting neutralizing antibodies (NAbs) against SARS-CoV-2 with the correlates of protection previously established for the ancestral (Wuhan) strain. The PNT assay was validated using nonmatched ancestral sera with anti-JN.1 cross-NAbs, clinically matched JN.1 sera with anti-JN.1 NAbs, or nonmatched JN.1 sera with anti-LP.8.1, KP.2, or KP.3 cross-reacting NAbs. In line with predefined validation acceptance criteria, the PNT assay was precise, with %GCV ≤ 50 in ~90–100%/200 results (40 samples/strain). The acceptance criteria were met for linearity (slope ranged from 1.041 for ancestral sera with anti-JN.1 NAbs to 1.213 for JN.1 sera with anti-KP.2 NAbs), R² (0.9619–0.9944 for ancestral sera with anti–JN.1 NAbs), % relative bias, and total %GCV < 50 for almost all of the 15 serum samples tested for four virus strains. Human sera collected pre–COVID-19 had no detectable titer for tested Omicron JN.1 subvariants (<LLOQ) and all influenza and RSV clinical samples tested negative (<LLOQ) for SARS-CoV-2 and highly immunogenic for seasonal influenza or RSV post-vaccination, demonstrating the PNT assay specificity. Our data suggest this assay is suitable for assessing immune responses to ancestral and current SARS-CoV-2 strains and has potential for evaluating cross-reacting NAbs against emerging Omicron JN.1 subvariants. Full article