Search Results (849)

Respiratory syncytial virus (RSV) remains a leading cause of lower respiratory tract infection (LRTI) and hospitalization in early infancy. Following the introduction of universal nirsevimab prophylaxis in Italy during the 2024–2025 RSV season, we evaluated its real-world effectiveness against RSV-associated hospitalization and severe clinical outcomes within a test-negative design framework. We conducted a multicenter retrospective test-negative study across 88 Italian neonatal centers, including infants hospitalized for LRTI from 1 September 2024 to 30 April 2025. Clinical data were collected from hospital records using a standardized electronic questionnaire. RSV-positive hospitalized infants were considered cases, and RSV-negative hospitalized infants served as controls. Secondary outcomes included respiratory support and Neonatal Intensive Care Unit (NICU) admission. Effectiveness was estimated using multivariable logistic regression and targeted maximum likelihood estimation. Overall, 737 infants were included, of whom 306 (41.52%) had previously received nirsevimab. RSV infection was identified in 398 infants (54.00%), including 104/306 (33.99%) nirsevimab-immunized and 294/431 (68.21%) non-immunized infants (p < 0.001). Immunized infants also required respiratory support less frequently (55.23% vs. 70.07%; p < 0.001), with lower use of high-flow oxygen therapy (40.85% vs. 48.96%; p = 0.036) and Continuous Positive Airway Pressure (CPAP) (18.95% vs. 33.87%; p < 0.001). Within the test-negative design framework, adjusted effectiveness against RSV-associated hospitalization was estimated at 78.3%. Among hospitalized infants, previous nirsevimab immunization was additionally associated with adjusted relative reductions in the odds of respiratory support and NICU admission of 80.2% and 64.3%, respectively. In conclusion, among infants hospitalized for LRTI in routine Italian clinical practice, previous nirsevimab immunization was associated with lower odds of RSV positivity and a reduced need for respiratory support. Although these findings provide further evidence of the real-world effectiveness of nirsevimab against severe RSV disease, further studies are needed to provide direct estimates of hospitalization incidence in immunized and non-immunized source populations. Full article

Background/Objectives: The approval of Abrysvo, a maternal bivalent respiratory syncytial virus (RSV) prefusion F (pre-F) vaccine, marked a major milestone in pediatric prophylaxis. However, real-world serological data on transplacental antibody transfer in Asian populations remains limited. This brief report evaluated serum RSV pre-F immunoglobulin G (IgG) geometric mean titers (GMTs) across three distinct Japanese cohorts. Methods: This single-center, comparative study analyzed neonates born to Abrysvo-vaccinated mothers (n = 12), neonates born to unvaccinated mothers (n = 40), and infants aged <6 months hospitalized with laboratory-confirmed RSV infection (n = 18) using enzyme-linked immunosorbent assay (ELISA). Results: Neonates of vaccinated mothers exhibited significantly higher pre-F IgG GMTs (4.74; 95% CI: 4.30–5.18) than those of unvaccinated mothers (3.80; 95% CI: 3.50–4.14). Conversely, infants requiring hospitalization for RSV infection demonstrated critically low pre-F IgG GMTs (1.08; 95% CI: 0.65–2.15), revealing statistically significant differences across all three groups (p < 0.001). Conclusions: Maternal immunization with Abrysvo significantly enhances passive humoral immunity in Japanese neonates compared to natural background immunity. Given the severe antibody deficiency observed in hospitalized infants, expanding maternal vaccination coverage is a high-priority public health strategy to mitigate the pediatric RSV burden in the post-pandemic era. Full article

Background/Objectives: Acute respiratory viral infections (ARVIs) are the leading cause of pediatric morbidity and exhibit considerable clinical heterogeneity. The analysis of clinical and etiological associations, as well as the identification of factors linked to severe ARVI cases, is essential for effective epidemiological surveillance. Methods: A retrospective, single-center observational study was conducted including 1362 non-COVID-19 pediatric cases of acute respiratory infections (ARIs), registered between 2021 and 2024. Viral pathogens were detected using real-time PCR for broad-spectrum screening of respiratory viruses. Results: Viral etiology was established in approximately 50% of cases. The most frequently detected pathogen was Human rhinovirus (HRV) (35.6%), followed by Respiratory syncytial virus (RSV) and Human adenovirus (HAdV). Despite its predominance, HRV did not demonstrate nosological specificity. The strongest associations with lower respiratory tract infections were identified for RSV (OR = 3.2) and Human bocavirus (HBoV; OR = 2.4), predominantly within the pneumonia category. RSV was also associated with bronchitis/bronchiolitis (OR = 1.8). Significant associations with upper respiratory tract infections were established for Influenza viruses (OR = 10.4) and HAdV, including nasopharyngitis (OR = 3.88) and acute tonsillitis (OR = 3.9). HAdV additionally demonstrated an association with otitis media (OR = 5.1). Severe disease was registered in 52.3% of all clinical observations and occurred most frequently among young children, particularly in cases associated with respiratory syncytial virus (RSV >80%), as well as with human bocavirus (HBoV) and Human metapneumovirus (HMPV) (~55–59%). Co-infections were not associated with increased disease severity compared with monoinfections (OR = 1.1). Conclusions: The obtained results highlight the contribution of specific etiological agents to severe respiratory infections in children. These findings support the prioritization of such pathogens in clinical diagnostics, including the design of diagnostic algorithms and the selection of patient management strategies in pediatric populations. Full article

Background: Bronchiolitis is a leading cause of hospitalization in infants, with respiratory syncytial virus (RSV) as the main etiological agent. The clinical relevance of respiratory pathogen co-infections and the role of emerging preventive strategies, including nirsevimab immunoprophylaxis, remain under investigation. Methods: We conducted two complementary observational analyses within the pediatric healthcare network of Western Sicily. The first was a retrospective study including 580 children younger than 24 months hospitalized for bronchiolitis between 2019 and 2025 at the “Giovanni Di Cristina” Hospital in Palermo, Italy, to investigate respiratory pathogen detection patterns and their clinical correlates. Patients were classified according to microbiological findings as single-virus infections or viral–viral/viral–bacterial co-detections. The second was a separate observational cohort of 458 newborns from two birth centers in Western Sicily during the 2024–2025 RSV season, established to evaluate the implementation, safety, and respiratory outcomes associated with nirsevimab prophylaxis. Results: Viral–viral and/or viral–bacterial co-detections were identified in 45.5% of hospitalized infants and were associated with longer hospital stay (8.86 vs. 6.35 days, p < 0.001) and a higher frequency of complications (18.6% vs. 8.5%, p < 0.001), without differences in age, sex, or respiratory support requirements. RSV remained the predominant pathogen throughout the study period. In the complementary observational subgroup analysis, the observed safety findings were reassuring, with only mild and self-limiting events reported during follow-up; however, the sample size and observational design limit the ability to assess rare or delayed adverse events. Among infants undergoing clinically indicated respiratory testing, RSV was detected in 7/9 (77.8%) non-prophylaxed infants and 5/24 (20.8%) prophylaxed infants. Among hospitalized infants, complications were less frequently observed among those who had received nirsevimab (3.5% vs. 26.9%, p < 0.001), although substantial baseline differences between groups precluded causal interpretation of this finding. Conclusions: Viral–viral and viral–bacterial co-detections are frequent in hospitalized bronchiolitis and are associated with increased clinical complexity, mainly through prolonged hospitalization and higher occurrence of complications. The observational nirsevimab analysis showed a favorable safety profile and a lower proportion of RSV detection among clinically tested prophylaxed infants. However, because respiratory testing was performed according to clinical indication and differed substantially between groups, these findings cannot be interpreted as estimates of RSV incidence or as definitive evidence of nirsevimab effectiveness. The observed difference in complications should also be interpreted cautiously because of substantial baseline differences between prophylaxed and non-prophylaxed infants. Prospective studies with systematic respiratory testing are warranted. Full article

Background/Objectives: The bivalent RSVpreF vaccine is effective at preventing respiratory syncytial virus (RSV)-associated lower respiratory tract illness in adults. However, data regarding safety and immunogenicity of RSVpreF in Korean populations are limited. Methods: This was a phase 3, multicenter, placebo-controlled, randomized (2:1), double-blind study in Korean adults 60 years of age and older. Participants received a single 120-μg dose of RSVpreF or matching placebo. Safety endpoints included local reactions and systemic events through 7 days and adverse events (AEs) through 1 month after vaccination, and serious AEs (SAEs) throughout the study. RSV-A and RSV-B serum 50% neutralizing geometric mean titers (GMTs) and geometric mean fold rises (GMFRs) were obtained 1 month after vaccination. Results: Overall, 377 participants received study intervention (RSVpreF, n = 251; placebo, n = 126). Most local reactions and all systemic events were of mild or moderate severity. Injection-site pain was the most frequently reported local reaction (RSVpreF, 12.4%; placebo, 3.2%). The most frequently reported systemic events were fatigue (RSVpreF, 23.1%; placebo, 26.2%) and muscle pain (RSVpreF, 15.5%; placebo, 9.5%). AEs through 1 month after vaccination were infrequent (RSVpreF, 3.6%; placebo, 0.8%); none were considered vaccine related by the investigator. RSV-A and RSV-B neutralizing GMTs increased 1 month after RSVpreF, with GMFRs (95% CIs) from before to 1 month after vaccination of 9.5 (8.51–10.67) for RSV-A and 8.3 (7.37–9.39) for RSV-B. Conclusions: In older Korean adults, RSVpreF had an acceptable safety and tolerability profile and elicited robust RSV neutralizing responses 1 month after vaccination consistent with pivotal phase 3 efficacy trial results. ClincalTrials.gov Identifier: NCT06593587 (date of registration: 9 September 2024). Full article

Background: Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract disease and hospitalization in early infancy. The availability of maternal RSVpreF vaccination and long-acting infant monoclonal antibodies has created two effective but operationally distinct pathways for passive protection. Methods: This WAidid consensus document focuses on maternal RSV immunization within an integrated early infancy prevention strategy. A multidisciplinary Consensus Development Group reviewed evidence on infant RSV burden and seasonality, maternal vaccine efficacy and effectiveness, transplacental antibody transfer, long-acting monoclonal antibodies, implementation, equity, and economic considerations. Recommendations were developed using a modified Delphi process with a prespecified consensus threshold of at least 75% agreement. Results: Maternal vaccination can provide protection from birth when administered sufficiently before delivery, whereas direct infant monoclonal antibody prophylaxis provides rapid protection independent of maternal immune response and placental transfer. The relative value of the two approaches depends on gestational age, vaccination-to-delivery interval, infant risk, birth timing, local RSV circulation, antenatal care access, product availability, and cost. Post-pandemic disruption of RSV seasonality increases the importance of flexible strategies that protect infants born outside historically defined seasonal windows. Direct head-to-head evidence remains limited; therefore, policy decisions should integrate trial efficacy, emerging real-world effectiveness, implementation feasibility, and local epidemiology rather than assume universal superiority of one strategy. Conclusions: Maternal vaccination and infant monoclonal antibodies should be positioned within a coordinated prevention pathway. Maternal vaccination may serve as the principal strategy for appropriately timed pregnancies with reliable antenatal access, while infant monoclonal antibodies are particularly important when maternal vaccination is absent, too close to delivery, or potentially ineffective, or when the infant is preterm or otherwise at increased risk. Surveillance and locally adapted implementation are essential to maintain protection as RSV epidemiology evolves. Full article

Early identification of children at risk of severe acute respiratory infection remains a clinical challenge. Although C-reactive protein (CRP), procalcitonin (PCT), and white blood cell (WBC) count are commonly assessed at hospital admission, their predictive value for severity assessment remains uncertain. We aimed to evaluate the utility of clinical features, a respiratory multiplex PCR test detecting 23 pathogens, imaging findings, and early inflammatory biomarkers in predicting subsequent supplemental oxygen requirement, used as a marker of severe acute lower respiratory infection (ALRI), among hospitalized children. The primary outcome was the need for supplemental oxygen during hospitalization. We conducted a single-center retrospective cohort study of children admitted to the pediatric department between May 2022 and June 2023 with ALRI or other conditions for which respiratory infection was considered but subsequently excluded. All included patients underwent multiplex respiratory PCR testing. We included 439 children in the analysis [median age, 20 mo (IQR: 5–54); 52.7% males]. Out of them, 178 (40.5%) required supplemental oxygen. The strongest positive association with subsequent supplemental oxygen requirement was observed for low oxygen saturation on admission [OR 8.83 (95% CI, 3.00–26.02; p < 0.001)], although this variable was documented in only about half of the cohort (52.4%). The strongest predictors of subsequent supplemental oxygen requirement in multivariable analysis were age, abnormal auscultatory findings, and the cumulative number of danger signs, including hypoxemia, tachypnea, dyspnea, and increased work of breathing. Among the 23 pathogens tested, respiratory syncytial virus (RSV) was the only pathogen consistently associated with a more severe course: 60.3% of RSV-positive children required supplemental oxygen, compared with 36.9% of RSV-negative children (OR 2.59, 95% CI 1.53–4.40; p < 0.001). For predicting subsequent supplemental oxygen requirement, no single marker had strong utility. These findings support the importance of structured bedside clinical assessment for identifying hospitalized children who may subsequently require supplemental oxygen. Given incomplete documentation of some vital signs, associations involving these variables should be interpreted with caution. Full article

Background: Respiratory tract infections (RTIs) caused by viruses are a public health problem, contributing to hospital admissions and morbidity worldwide. The COVID-19 pandemic substantially altered the detection patterns of respiratory viruses through public health interventions. Longitudinal data on these changes and viral seasonality remain limited in Saudi Arabia. This eight-year study evaluated epidemiological and seasonal patterns of major respiratory viruses across the COVID-19 era at a major Saudi tertiary care center. Methods: A retrospective observational study was conducted at King Khalid University Hospital, Riyadh, from October 2017 to December 2025. PCR-confirmed detections for SARS-CoV-2, Influenza A, Influenza B, respiratory syncytial virus (RSV), and human metapneumovirus (HMPV) were extracted from the hospital Laboratory Information System. Demographics, co-detection, seasonality, and length of stay (LOS) were analyzed across four eras spanning the pre-COVID-19, lockdown, restriction, and post-restriction periods using descriptive statistics, the Kruskal–Wallis test, and multivariable negative binomial regression. Results: Among 5708 confirmed respiratory viral detection episodes, SARS-CoV-2 was the most frequently detected (52.5%), followed by Influenza A (19.1%), RSV (16.4%), Influenza B (8.4%), and HMPV (3.6%). Before the pandemic, Influenza A accounted for the largest proportion of detected episodes (71.1%), with detections clustering particularly during autumn and winter seasons, whereas SARS-CoV-2 accounted for the majority of detected episodes during the lockdown and restriction eras (97.4% and 93.2%). The post-restriction era became more diverse, with RSV being detected in substantial proportions (28.3%), showing prominent winter activity. RSV and HMPV predominantly affected children aged 0–5 years, whereas SARS-CoV-2 was more frequently detected among older adults. Among adults, older age was associated with prolonged LOS; Influenza A and HMPV were associated with shorter stays compared to SARS-CoV-2. Among children, no virus was independently associated with LOS after adjustment for age and sex; however, older age was associated with longer hospital stays. Conclusion: The observed detection patterns of major respiratory viruses shifted substantially across the COVID-19 eras, with notable post-restriction diversification among observed positive detections. LOS was associated with age in both adults and children and with virus type among adults, supporting continued surveillance to guide preventive and clinical strategies. Full article

Background: Community-acquired respiratory viruses (CARVs) cause significant morbidity and mortality in patients with haematological malignancies and those undergoing haematopoietic cell transplantation (HCT). Despite this, clinical management remains variable. This study evaluated clinicians’ awareness, diagnostic practices, and treatment approaches to major respiratory viruses in this high-risk population. Methods: An international electronic survey using non-probability convenience sampling was conducted among haematology, oncology, intensive care and emergency medicine physicians. Four real-life clinical cases were converted into standardised vignettes covering human metapneumovirus (HMPV), respiratory syncytial virus (RSV), human parainfluenza virus (HPIV) and influenza A virus (IAV). The questionnaire assessed reported testing strategies and intended management, including antiviral and immunoprophylactic interventions. Responses were analysed descriptively; no inferential between-group comparisons were performed. Results: Ninety-eight clinicians from 26 countries responded. Diagnostic approaches, including testing indications and panel selection, varied among respondents. For HMPV and HPIV, respondents mainly reported supportive care, immunoglobulin replacement, and infection-control measures in the absence of established pathogen-specific interventions. RSV practice was heterogeneous: systemic ribavirin was considered by 45/96 (46.9%) respondents, including 34/96 (35.4%) when guided by an immunodeficiency score. IAV management was more consistent, with reported availability of vaccination and antiviral therapy and frequent use of post-exposure prophylaxis. Conclusions: Within this international convenience sample, clinicians reported variation in respiratory viral testing and in how results informed intended management. Because sampling was non-probability-based and respondent groups were small and unevenly distributed, the findings should not be interpreted as representative estimates of international practice. IAV testing was most consistently linked to established treatment and prevention, RSV showed greater therapeutic and preventive heterogeneity, and HMPV/HPIV testing primarily informed infection control, monitoring and antimicrobial stewardship. Full article

Human respiratory viruses represent a major global health burden, causing millions of severe infections and deaths annually. Despite the central role of vaccines in prevention, their limitations, such as incomplete coverage, waning immunity, and vulnerability to viral evolution, underscore the urgent need for effective antiviral therapeutics. This review examines the principles and applications of target-based antiviral drug development against human respiratory viruses, emphasizing the identification and exploitation of conserved viral and host targets. Key viral proteins, including RNA-dependent RNA polymerases, proteases, and fusion glycoproteins, are analyzed across major virus families such as coronaviruses, paramyxoviruses, and adenoviruses, highlighting their structural features, functional constraints, and therapeutic potential. We further explore the integration of high-throughput screening and rational drug design, supported by advances in structural biology, cryo-electron microscopy, and computational approaches, including artificial intelligence-driven drug discovery. These methodologies collectively enhance the precision and efficiency of antiviral development. However, significant challenges remain, particularly the conflict between viral mutation and target conservation, the rapid emergence of drug resistance, and the safety limitations of host-targeted therapies. Finally, we discuss emerging strategies to overcome these barriers, including combination therapies and the development of broad-spectrum antivirals targeting conserved molecular mechanisms. This paper highlights a framework for the rational design of durable antiviral interventions capable of addressing both existing and emerging respiratory viral threats. Full article

Background: Long-acting monoclonal antibodies have become an important strategy for preventing respiratory syncytial virus (RSV) disease in infants. Nirsevimab is the first product for which substantial post-licensure implementation data are available, whereas real-world evidence on clesrovimab remains limited. Although nirsevimab has demonstrated high efficacy, its uptake varies considerably across countries, healthcare systems, delivery settings, and population subgroups. This World Association for Infectious Diseases and Immunological Disorders (WAidid) consensus document examines the policy, organizational, economic, and equity-related determinants that shape real-world implementation of long-acting monoclonal antibodies for infant RSV prevention. Methods: This study was conducted as a structured narrative review and WAidid expert consensus document. A structured literature search was performed in PubMed and Embase for English-language publications relevant to nirsevimab uptake and implementation, complemented by targeted review of surveillance reports, policy documents, and public health guidance from the ECDC, UKHSA, and CDC, as well as reference lists of selected publications. Eligible sources included observational and real-world implementation studies, systematic reviews and meta-analyses, economic evaluations, guidelines, policy statements, surveillance reports, and relevant narrative reviews. Evidence was synthesized qualitatively according to policy frameworks, financing and reimbursement, delivery pathways, demographic and socioeconomic determinants, and healthcare-system factors influencing uptake. No statistical software was used because no quantitative re-analysis or meta-analysis was performed. Results: Nirsevimab uptake was strongly influenced by national RSV prevention policies, particularly whether countries adopted universal infant monoclonal antibody programs, maternal RSV vaccination strategies, dual maternal–infant approaches, or targeted risk-based models. Universal, publicly funded programs integrated into neonatal care achieved the highest and most homogeneous coverage, especially when administration occurred before hospital discharge and was supported by registry-based recall systems for infants born outside the RSV season. In contrast, fragmented, outpatient-only, insurance-dependent, or partially reimbursed models were associated with lower, delayed, or more variable uptake. Additional determinants included product cost, reimbursement pathways, provider practices, caregiver awareness and health literacy, insurance status, income, race and ethnicity, geographic deprivation, and access to primary pediatric care. Most available evidence comes from high-income countries, limiting generalizability to low- and middle-income settings, where RSV burden is greatest and implementation constraints may differ. Conclusions: Successful implementation of long-acting monoclonal antibodies for infant RSV prevention requires more than regulatory approval and demonstrated efficacy. Equitable uptake depends on clear national recommendations, sustainable public financing, reliable product supply, integration into neonatal and primary pediatric care, proactive identification and recall of eligible infants, and targeted strategies to reduce socioeconomic and geographic disparities. Although many determinants identified in high-income settings are likely relevant globally, their feasibility, relative importance, and impact require dedicated evaluation in low- and middle-income countries. Full article

Background/Objectives: Respiratory syncytial virus (RSV) causes morbidity in older adults with cardiovascular disease, in whom infection may precipitate severe lower respiratory tract disease, hospitalization, functional decline, and cardiovascular destabilization. We evaluate the evidence for RSV vaccination in cardiovascular disease and propose a jurisdiction-adaptable framework for integrating vaccination into cardiovascular care. Methods: Observational studies, randomized trials, pragmatic and test-negative studies, prespecified cardiovascular analyses of DAN-RSV, and eligibility recommendations were narratively synthesized and translated into a pathway encompassing patient identification, eligibility and risk assessment, vaccine delivery and co-administration, documentation, and follow-up. Results: Acute cardiac events are frequent during RSV hospitalization, and cardiovascular risk may persist after infection. Randomized trials establish protection against RSV-associated lower respiratory tract disease and respiratory illness, while real-world studies support effectiveness against RSV-related hospitalization. DAN-RSV reduced all-cause cardiorespiratory hospitalization but did not demonstrate significant reductions in cardiovascular hospitalization, myocardial infarction, heart failure (HF) hospitalization, atrial fibrillation, stroke, cardiovascular death, or major adverse cardiovascular events; observational associations with lower post-vaccination cardiovascular-event rates remain hypothesis-generating. The framework prioritizes adults aged ≥75 years and those aged 50–74 years with high-risk cardiovascular conditions where consistent with national recommendations, embeds vaccination assessment across cardiology, HF, primary care, pharmacy, and long-term care, and incorporates co-administration, documentation, and outcome surveillance. Conclusions: The principal contribution is a pathway for moving RSV vaccination from recommendation to routine preventive care for adults with cardiovascular disease. It anchors implementation in established RSV and cardiorespiratory benefits while treating cardiovascular-event reduction as a research priority rather than a demonstrated indication. Full article

Background: Clinical trials of respiratory syncytial virus (RSV) monoclonal antibodies (mAbs) have followed participants for up to 180 days, covering a typical single RSV season. However, to assess the full clinical impact of mAb administration, post-trial efficacy estimates are needed, particularly in countries where RSV circulation extends beyond six months. Methods: In this study, we applied a previously published Bayesian framework to estimate how the level of protective efficacy against RSV provided by clesrovimab and nirsevimab changes over the first year after administration. Using this Bayesian framework, which modeled new infections as Poisson processes with a Gaussian process prior for the force of infection and a parametric waning function for the intervention arm, we estimated placebo incidence rates and posterior waning functions. We validated our estimates by calculating model-estimated cumulative trial-period efficacy using an Incidence Rate Ratio (IRR) approach and by reconstructing event-free probability curves, comparing both with published clinical trial results. Results: Model-derived cumulative efficacy estimates closely matched trial-reported results for both products. The model-projected instantaneous probability of being protected at one year—an extrapolation beyond the observed trial follow-up—was 24.6% (95% CrI: 1.6–57.0%) for clesrovimab and 12.8% (95% CrI: 1.2–44.4%) for nirsevimab, with substantially overlapping credible intervals. Conclusions: Both RSV mAbs were projected to provide some level of protection throughout the first year following administration, with broadly similar levels of protection. Full article

Background/Objectives: Neurocognitive disorders represent a growing burden among older adults. Although respiratory vaccines have demonstrated efficacy and safety in preventing acute respiratory events, their potential impact on the development of chronic neurocognitive disorders, such as cognitive impairment, dementia, and Alzheimer’s disease (AD), has not been extensively explored. The objective of this scoping review was to synthesize and analyze the available evidence on the association between respiratory vaccination and the risk of developing cognitive impairment, dementia, and Alzheimer’s disease. Methods: A scoping review was conducted in accordance with the PRISMA-ScR guidelines. A literature search was performed in the PubMed, Scopus, and Web of Science databases through 15 June 2026. Studies involving older adults (≥60 years), irrespective of their baseline neurocognitive status, were included. Observational studies (cohort and case–control studies) were considered. Editorials, narrative reviews, and other non-original articles were excluded. Results: Eighteen studies were included, with cohort studies being the predominant design. Four main categories of respiratory vaccines were evaluated: influenza, COVID-19, respiratory syncytial virus (RSV), and pneumococcal vaccines, in relation to the risk of cognitive impairment, dementia, and AD. Influenza vaccination was associated with a lower risk of dementia and AD, with a potential dose–response relationship observed, whereby a greater number of vaccinations was associated with a greater reduction in risk. Pneumococcal vaccination was also associated with a lower risk of dementia and AD, particularly among individuals who received a greater number of vaccine doses. In contrast, the evidence regarding COVID-19 and RSV vaccines was limited and yielded heterogeneous findings. Conclusions: Influenza and pneumococcal vaccination maybe associated with a lower risk of Alzheimer’s disease and dementia. However, the evidence regarding COVID-19 and RSV vaccines remains limited, and additional studies are needed to clarify their impact on the risk of developing neurocognitive disorders. Full article