Search Results (265)

Background: The elicitation of broadly neutralizing antibodies against conserved antigenic epitopes has been a focus of universal vaccine research. To facilitate immunofocusing on the conserved influenza hemagglutinin (HA) stalk, we designed headless trimeric antigens, initially focusing on subtypes H1, H3, and H5, and subsequently expanding to eight additional HA subtypes. Results: The designs were first evaluated in silico; they were predicted to fold correctly by AlphaFold2, and remained stable in molecular dynamics simulations in isolation, as well as bound to a broadly neutralizing antibody. The antigens expressed in HEK293-derived cells in high yields, and eluted predominantly as trimers in SEC-HPLC. Future work will explore the use of mosaic nanoparticles decorated with headless antigens of various subtypes for the optimal elicitation of broadly neutralizing anti-influenza antibodies. Overall, our study advances the use of headless HA trimers as modular antigens toward a universal influenza vaccine. Full article

Background: Despite the increased infection-related morbidity of patients with chronic kidney disease (CKD), their vaccination coverage is low. Cocooning strategy has not been adequately researched in this group. Our aim was to evaluate vaccination coverage of CKD pediatric and adult patients and their families. Methods: In this prospective, single-center study, we recorded the vaccination coverage of CKD pediatric and adult patients and their families who attend a tertiary University Hospital. Vaccination rates were calculated according to the national vaccination program. Vaccination of pediatric CKD patients was compared to a control group of healthy children. Results: The vaccination rate of 63 hemodialysis patients was low for influenza (61.9%), COVID-19 (79.4% primary, 3.2% booster doses), RSV (50%), herpes zoster (42.4%), hepatitis B (41.3%), Streptococcus pneumoniae (25.4%), tetanus–pertussis (3.2%), and HPV (0%). Their 30 underaged relatives had low vaccination rates for influenza (13.3%), DTaP/Tdap (80%), and Men B (50%), with adequate vaccination for other pathogens. The 53 children with CKD were poorly vaccinated for influenza (20.8%), COVID-19 (0%), Streptococcus pneumoniae (15.4%), Men B (30.2%), DTaP/Tdap (67.9%), MMR (78.8%) and VZV (86.5%), but their vaccination rates for influenza were significantly higher compared to controls. Their 108 adult relatives were inadequately vaccinated for influenza (27.8%), COVID-19 (1.9%), and Tdap (1.9%). Their 35 underaged relatives were poorly vaccinated for influenza (22.9%) and DTaP (80%). Conclusions: Vaccination coverage of CKD patients is suboptimal for vaccines particularly important for their condition and their family members are insufficiently informed about potential contribution to their protection by cocooning strategy. Full article

Background: Sickness absenteeism has long been an organizational problem due to the consequent loss of productivity (1–2% of gross domestic product in European Union countries) and job overload for workers. We designed and conducted an observational cohort study to describe and analyze the short sickness events and their derived absence days in a large university tertiary hospital, also incorporating the fit for work assessment and the anti-influenza vaccination coverage. Materials and Methods: The anonymous data of workers with at least one day of certified presence during the period 1 January–31 August 2025 were extracted from the hospital information system. Crude and job-specific absence rates were calculated. The incidence rate ratios (IRRs) along with their 99% confidence intervals for the covariates were obtained by a negative binomial model fit. Results: The overall sickness event rate was 0.54 per 100 person-workdays, ranging from 0.22 (physicians) to 0.92 (technical/administrative staff), while the overall sickness day rate was 0.88 per 100 person-workdays, spanning from 0.31 (physicians) to 1.41 (health and social care assistants). The multi-variable model fit of sickness days returned significant IRRs for being vaccinated (0.74; 99% CI: 0.58–0.93), for male gender (0.77; 99% CI: 0.63–0.95) and for limitations regarding the fitness for work assessment (2.14; 99% CI: 1.51–3.05). Conclusions: Our findings indicate that, in a large tertiary university hospital, an anti-influenza vaccination campaign may effectively protect workers from sickness absences, even accounting for gender, age and regardless of job typology and fit for work assessment. Furthermore, the health risk of the technical/administrative job category might be underestimated. Finally, our results seem to suggest that workers with limitations might be “fragile”, or more vulnerable, than expected in a broader sense of the term, both from nosological and temporal points of view. Further research with a higher level of evidence is needed to verify and confirm these findings. Full article

Background: In the context of a multi-stakeholder program promoted by Regione Lombardia in collaboration with Fondazione The Bridge and the University of Pavia, the present study investigates the organization and availability of hospital-based vaccination services for high-risk patients. Framing hospitals as strategic hubs for vaccination delivery, the study aimed to map service availability, operational settings and dedicated pathways across the region. Methods: A structured questionnaire was administered in 2025 to 40 healthcare organizations, encompassing 114 hospital facilities, including Local Health and Social Care Authorities (ASSTs) and both public and private Scientific Institutes for Research, Hospitalization and Healthcare (IRCCSs). Descriptive and inferential statistical analyses were performed, and findings were compared with those from the 2023 and 2024 editions of the same survey, developed within the “Vaccination—an opportunity for high-risk patients” project, using Pearson’s chi-square test. Results: In 2025, 99 facilities (86.8% of respondents) reported providing vaccination services for at-risk individuals. Dedicated vaccination pathways were generally available in more than 50% of facilities for nearly two-thirds of the risk categories considered. Vaccination services for diabetic patients were available in 70.7% of facilities. Among healthcare workers, influenza (93%) and SARS-CoV-2 (89.5%) vaccines were the most frequently offered, with rates approximately ten percentage points higher than those of other vaccines. Conclusions: Overall, these findings indicate a regional model progressively consolidating hospital-based vaccination for high-risk groups, with a consistent upward trend in service availability from 2023 to 2025. Full article

Background. The highly mutable influenza virus causes severe annual infections worldwide and results in substantial socioeconomic losses. The spread of infection could be effectively controlled by cross-protective vaccines and universal diagnostic test systems based on the nucleoprotein (NP) as one of the most conserved viral antigens. However, NP also undergoes slow evolutionary changes, and little is known about the influence of these mutations on its antigenicity and immunogenicity. Methods. We expressed the full-length recombinant 6xHis-tagged NPs of ten evolutionary distant influenza A strains of different subtypes in E. coli BL21(DE3) cells and purified these proteins by immobilized metal affinity chromatography. The obtained antigens were identified by mass spectrometry and serological methods. NPs served as antigens for three immunizations of BALB/c mice (15 µg/animal at 14-day interval) and as capturing proteins in ELISA at 2 µg/mL, in order to study the effect of adaptive mutations on the antigenic and immunogenic properties of NPs. Results. A pronounced cross-reactivity of anti-NP antibodies induced in mice by immunization with different NPs was revealed. At the same time, we observed the differences in the humoral immunogenicity of NP, which are in line with the accumulation of evolutionarily driven NP mutations. In general, antibody affinity to heterologous NPs was reduced, indicating the differences in the specificity of anti-NP immunoglobulins, which may be caused by evolutionarily determined variability of immunogenic epitopes leading to the emergence of escape mutations. Conclusions. Overall, our results reflect the slightly evolving nature of the NP antigen, which influences the specificity spectrum of anti-NP antibodies and should be considered as a limitation for the development of NP-based cross-protective vaccines and test systems. Full article

Objective: Influenza and pertussis vaccines are recommended during pregnancy; however, uptake remains insufficient in many European countries, increasing the risk of preventable infections. Recent recommendations for maternal respiratory syncytial virus vaccination have been endorsed by scientific societies. This study evaluated maternal vaccination coverage, knowledge, attitudes, and factors influencing vaccine uptake among Lithuanian women. Methods: A retrospective cross-sectional online survey was conducted between 4 and 14 November 2025 in Lithuania among women aged 18–55 years with at least one previous pregnancy. The questionnaire contained 29 questions on sociodemographic characteristics, obstetric history, vaccination history, attitudes, and informational sources influencing decisions. Internal reliability was confirmed (Cronbach’s α = 0.83). Descriptive statistics were used to summarize the data. Associations between categorical variables were assessed using the Chi-square test or exact tests (Fisher’s exact or Fisher–Freeman–Halton). Binary and multivariable logistic regression analyses were performed to evaluate factors associated with self-reported vaccination uptake and the relationship between influenza and pertussis vaccination. Odds ratios with 95% confidence intervals were calculated. Statistical significance was set at p < 0.05. Results: A total of 241 women participated. Self-reported vaccination coverage during pregnancy was 28.7% for influenza, 43.8% for tetanus–diphtheria–pertussis, and 4.2% for respiratory syncytial virus. Physician’s recommendation was the strongest predictor: women advised to vaccinate were 17.0 times more likely to receive influenza, 16.5 times more likely to receive pertussis, while RSV vaccination occurred almost exclusively among women who reported receiving a physician’s recommendation. Higher uptake was associated with younger maternal age and university education. Reasons for declining vaccination were avoidance of medical interventions and concerns about safety or side effects. Conclusions: Maternal vaccination coverage in Lithuania remains low despite public funding and national recommendations. Strengthening provider communication, improving information strategies, and integrating vaccination counseling into routine antenatal care may increase uptake and enhance maternal and neonatal protection. Full article

Background: During the flu season, there is an increase in absenteeism due to illness, a drop in productivity, and a greater risk of the virus spreading among workers. Thus, the Italian Ministry of Health recommends vaccination for essential service workers. The University of Salerno, in collaboration with the local health authority of Salerno, offers free vaccination to its employees. Methods: A public health methodology for seasonal influenza vaccination in the workplace is presented—specifically in the university setting—with the aim of identifying individual, contextual, and organizational elements of the model that have promoted vaccination uptake. An ad hoc questionnaire was used (October–December 2025) to survey 399 academic employees, investigating seasonal influenza vaccination in the following aspects: recent personal experiences, motivations, vaccination experiences at university, sources of information, considerations regarding national and local vaccination campaigns, and level of vaccine confidence (VCI). Results: Seasonal influenza vaccination at the University is appreciated for its compatibility with working hours (66.1%), the availability of a platform that allows flexible booking (56.9%), the perception of safety in the environment (31.6%), the fact that the vaccine is free (17.4%), and the involvement of office/laboratory colleagues (5%). Participants appreciate the model and would apply it to other vaccinations at the University and in other institutional settings. A significant relationship (F = 7.24; df = 1; p < 0.05) exists between confidence in the vaccine and the sense of security experienced when receiving the vaccine in the workplace. Data analysis was performed using the IBM SPSS v.28 software. Conclusions: The model proposed can be applied to other institutional contexts, simplifying and facilitating access to vaccines by implementing vaccination campaigns tailored to specific work environments. Full article

Background/Objectives: Influenza A (IAV) and influenza B (IBV) viruses pose significant public health threats, with varying epidemiology and immune responses. Limited subtype-specific cytokine data exist for influenza in Saudi Arabia. This study conducted molecular surveillance on 380 NPAs from patients at King Khalid University Hospital (KKUH) in Riyadh, Saudi Arabia, during winter seasons (2020–2023). Methods: NPA samples were collected from hospitalized patients presenting with fever (>38 °C) and respiratory symptoms. RNA was extracted using the QIAamp Viral RNA Kit, followed by RT-PCR for IAV (H1N1, A/H3N2) and IBV detection. Quantitative real-time PCR profiled mRNA expression of 17 cytokines/chemokines in IAV-positive (n = 65) and IBV-positive (n = 20) samples, normalized to GAPDH using the 2^−ΔΔCq method. Appropriate statistical tests were applied (p < 0.05 significant). Results: Results showed 17.11% IAV positivity (7.89% A/H1N1, 9.21% A/H3N2) and 5.26% IBV. A/H3N2 predominated, increasing from 6.67% (2020/21) to 12.30% (2022/23). Males had higher IAV rates (25.88% vs. 10.00% females, p < 0.05), while IBV was higher in females (6.67% vs. 3.53%). Age-wise, 0–4 years had peak IAV (28.42%, p < 0.05); IBV peaked at 5–14 years (10.91%). IAV elicited higher mRNA expression IFN-α, IL-10, IL-13, and CCL-2 (p < 0.05); IBV showed elevated IL-1α, IL-6, and IL-33 (p < 0.05). Within IAV, A/H1N1 had higher IL-4, IL-10, IL-13, and IL-17; A/H3N2 elevated TNF-α, IL-6, IL-22, CCL-3, and CCL-4 (p < 0.05). Conclusions: These findings highlight subtype-specific inflammatory profiles and demographic disparities in Saudi Arabia, informing targeted interventions. Post-COVID resurgence underscores surveillance needs amid travel and gatherings. Insights into cytokine dynamics aid prognosis and therapeutics, emphasizing regional molecular monitoring for vaccine optimization and outbreak prevention. Full article

Background: Influenza B virus (IBV) undergoes continuous genetic mutations that can affect vaccine effectiveness and immune evasion. Although considerable research on IBV epidemiology exists globally, understanding of its genetic behavior in Saudi Arabia remains limited. This study characterized the molecular epidemiology of IBV in Riyadh, Saudi Arabia, during the 2024–2025 influenza season and evaluated compatibility with the current vaccine strain. Methods: Nasopharyngeal samples (n = 363) were collected from individuals presenting with influenza-like illness at King Khalid University Hospital in Riyadh. Detection and subtyping of IBV were performed using RT-PCR. Complete sequencing of the hemagglutinin (HA) and neuraminidase (NA) genes was conducted on confirmed IBV isolates (n = 7), followed by phylogenetic analysis, amino acid substitution mapping, and glycosylation site prediction. Results: Of the 363 samples analyzed, 68 (18.7%) tested positive for IBV, with the majority occurring in adult females aged 15–64 years. Phylogenetic analysis revealed that all seven IBV isolates belonged to the Victoria lineage under subclade V1A.3a.2, corresponding to the current vaccine strain and strains from the 2022–2023 epidemic season. However, molecular analysis identified two substitutions (D129N and D197E) located in antigenic loop-150 and 190-helix, respectively, in the HA polypeptide that distinguished our strains from vaccine strain B/Austria/1359417/2021. Importantly, the N-glycosylation site at position 169 (NKT), which was present in B/Riyadh/1/2010, has been lost in the IBV strains circulating during 2020–2025. Conclusions: While phylogenetic clade compatibility indicates potential vaccine efficacy, the identified amino acid variations and loss of the glycosylation site underscore the necessity for ongoing molecular surveillance to monitor antigenic changes and evaluate vaccine effectiveness within the Saudi Arabian population. Full article

Background/Objectives: Seasonal influenza imposes a significant burden on pediatric public health. Despite official recommendations and full insurance coverage, vaccination rates among children in Slovakia remain critically low. This study aims to analyze the attitudes, beliefs, and determinants of parental hesitancy regarding childhood influenza vaccination in the post-pandemic context. Methods: A single-center cross-sectional survey was conducted between February and March 2025 using convenience sampling among parents of children attending a pediatric immunoallergology center. An anonymous questionnaire collected data on demographics, risk perception, and attitudes. Data from 301 parents were analyzed using descriptive statistics, chi-squared tests, and odds ratios (OR) to identify key predictors of hesitancy. Results: Only 27.6% of parents expressed willingness to vaccinate their children, while 42.5% were opposed and 29.9% hesitant. Statistical analysis revealed no significant association between parental university education and vaccination intent (p > 0.05), indicating that vaccine hesitancy in this specific setting was present across all educational backgrounds. However, the source of information proved to be a critical determinant: consulting a pediatrician significantly increased the odds of acceptance (OR = 6.32; 95% CI: 3.54–11.28), whereas reliance on the internet and social media was a significant predictor of refusal (OR = 0.29; 95% CI: 0.17–0.50). The primary reported barrier was fear of adverse effects (70.4%), which significantly outweighed doubts about efficacy (30.2%). Conclusions: Parental hesitancy in Slovakia is a widespread phenomenon pervasive across all educational backgrounds, driven primarily by safety concerns and digital misinformation. The contrast between the protective influence of pediatricians and the negative impact of digital media underscores that clinical encounters are currently the most effective firewall against hesitancy. Public health strategies must therefore pivot from general education to empowering pediatricians with active, presumptive communication strategies. Full article

Background/Objective: The influenza virus remains one of the most prevalent respiratory pathogens, posing significant global health and economic challenges. According to the World Health Organization, the seasonal influenza virus infects up to 1 billion people and causes up to 650,000 deaths, annually. Despite influenza vaccination is the most effective available preventive strategy, its reliance on strain predictions and yearly updates limits its effectiveness. The virus’ ability to cause both epidemics and pandemics, driven by zoonotic transmissions, underscores its continuous threat. The ongoing H5N1 avian influenza outbreak is the perfect example, renewing concerns due to its ability to infect over 70 mammalian species and sporadically transmit to humans. This study aims to evaluate the protective potential of two human monoclonal antibodies against diverse and recent influenza virus strains. Method: PN-SIA28 and PN-SIA49 monoclonal antibodies were previously isolated from an individual undergoing seasonal influenza vaccination and with no known recent influenza virus exposure. Their breadth of recognition, neutralization, and conferred in vivo protection were assessed against multiple influenza viruses, including pre-pandemic strains. Structural analyses were performed to characterize antibody–antigen interactions for epitope identification. Results: Both antibodies recognize a broad range of strains and neutralize pre-pandemic avian influenza viruses, including the currently circulating H5N1 clade. Moreover, a structural analysis revealed that PN-SIA49 binds a conserved HA stem region, overlapping with epitopes recognized by other broadly neutralizing antibodies. Conclusions: These findings underscore the potential of broadly neutralizing antibodies as a basis for universal influenza countermeasures against both seasonal and pandemic threats. Additionally, they provide guidance for the design of targeted vaccine strategies to steer immune responses toward broadly protective epitopes. Full article

Background/Objectives: The current strategy for seasonal influenza prophylaxis relies on updating the vaccine components annually to account for the rapid antigenic drift of viruses and the low cross-protective efficacy of available vaccines. Mutant influenza viruses with truncated or deleted NS1 protein are known to stimulate cross-specific T-cell immune response and provide protection against heterosubtypic influenza A and B viruses. Methods: We generated NS1ΔC influenza A and B viruses with C-terminal NS1 deletions by reverse genetics. In a mouse model, we assessed the safety and immunogenicity of the B/Lee/NS1ΔC strain upon intranasal administration, as well as the mechanism of its cross-protective efficacy against sublethal B/Victoria and B/Yamagata challenges. We then investigated the potential of the intranasal Flu/NS1ΔC vaccine–a trivalent formulation of NS1ΔC A/H1N1, A/H3N2, and B influenza viruses–to protect mice from lethal influenza infection with homologous, heterologous, and antigenically drifted influenza A and B viruses. Results: Intranasal immunization with the B/Lee/NS1ΔC strain was safe in mice. It activated cross-specific T-cell responses in the lungs and protected animals against heterologous challenge by reducing viral load, inflammation, and lung pathology. Immunization with the trivalent Flu/NS1ΔC vaccine formulation improved survival and reduced weight loss and viral load upon challenge with A/H1N1pdm, A/H2N2, A/H5N1, and B/Victoria viruses. Conclusions: The trivalent intranasal Flu/NS1ΔC influenza vaccine is a promising tool to improve seasonal influenza protection and preparedness for an influenza pandemic. Full article

Background/Objectives: Seasonal influenza is a global public health issue, and influenza vaccination is the most effective preventive measure. Nursing students are at a higher risk of contracting it due to clinical exposure. However, vaccination uptake among nursing students remains low. This study examines seasonal influenza vaccination uptake rates and the predictors of nursing students’ willingness to receive this vaccine. Methods: A cross-sectional online study was conducted using a well-validated questionnaire in order to collect data from a convenience sample of nursing students in Hong Kong from early November to early December 2024. Results: Out of the 461 valid responses received, 67.5% were from females, with a mean age of 20.53 (SD = 2.16) years. Vaccination history was diverse: 34.3% reported that they underwent influenza vaccination in the most recent season, 49.7% reported that they were vaccinated one to two times over the preceding five years, and only 5% reported that they undergo vaccination annually. A logistic regression model showed that the respondents who had been vaccinated against influenza in the most recent years (OR = 2.881, 95% CI: 1.773–4.680) had been vaccinated against influenza 1–2 times (OR = 3.239, 95% CI: 1.750–5.993), had been vaccinated 3–4 times (OR = 3.984, 95% CI: 1.773–8.957), had been vaccinated every year (OR = 10.353, 95% CI: 3.025–35.436) in the past five years, and had a higher score of perceived susceptibility (OR = 2.244, 95% CI: 1.302–3.867) were more likely to intend to be vaccinated with an influenza vaccine in the coming year. Conclusions: Annual seasonal influenza vaccination rates among nursing students remain low, though they have improved. We recommend that the Hong Kong government, healthcare organizations, and universities develop effective strategies for promoting annual seasonal influenza vaccination to safeguard both patients’ health and the health of future nursing professionals. Full article

Background/Objectives: Seasonal influenza, pneumococcal disease, and COVID-19 pose major public health challenges, particularly for individuals with chronic illnesses. This study examined vaccination coverage for influenza, pneumococcal disease, and SARS-CoV-2 among patients with chronic liver disease and cirrhosis and explored the sociodemographic and clinical factors influencing it. Methods: A cross-sectional study, conducted from March 2022 to July 2023 at two university hepatology outpatient clinics in Athens, Greece. The study population consisted of patients with a diagnosis of chronic liver disease (hepatocellular carcinoma and hepatitis) and liver cirrhosis. Results: A convenience sample size of 300 patients (age ≥ 30) participated. Regarding their vaccination, 88.3% were vaccinated against SAR-COVID-19, 44.8% against pneumococcus, and 54.7% against seasonal influenza this year. Patients’ belief that annual vaccination is the best method for influenza prevention was found to be significantly higher among older patients and those with comorbidities. Additionally, patients who had been vaccinated against seasonal influenza (this year or every year), against pneumococcus, or SARS-CoV-2 agreed significantly that annual vaccination is the best method for influenza prevention. In addition, patients who were informed about vaccination by their doctor/nurse agreed significantly more with that. Multiple logistic regression found that a four times greater probability of being fully vaccinated according to the national vaccination program was found in patients who were informed about vaccination by a doctor/nurse. Moreover, as patients’ age increased, so did the probability of being fully vaccinated. Conclusions: The study’s findings are significant and can be utilized within national public health initiatives and by healthcare professionals during patient interactions, ensuring that younger patients and those apprehensive about vaccine efficacy and safety receive focused attention to facilitate adherence to annual vaccinations and all vaccines included in national programs. Full article

Influenza viruses remain a major global public health concern, causing significant morbidity and mortality annually despite widespread vaccination efforts. The limitations of current seasonal vaccines, including strain-specific efficacy and manufacturing delays, have accelerated the development of next-generation candidates aiming for universal protection. This review comprehensively summarizes the recent progress in universal influenza vaccine research. We first outline the key conserved antigenic targets, such as the hemagglutinin (HA) stem, neuraminidase (NA), and matrix proteins (M2e, NP, and M1), which are crucial for eliciting broad cross-reactive immunity. We then delve into advanced antigen design strategies, including immunofocusing, multi-antigen combinations, computationally optimized broadly reactive antigens (COBRA), and nanoparticle-based platforms. Furthermore, we evaluate evolving vaccine delivery systems, from traditional inactivated and live-attenuated vaccines to modern mRNA and viral vector platforms, alongside the critical role of novel adjuvants in enhancing immune responses. The convergence of these disciplines—structural biology, computational design, and nanotechnology—is driving the field toward a transformative goal. We conclude that the successful development of a universal influenza vaccine will likely depend on the strategic integration of these innovative approaches to overcome existing immunological and logistical challenges, ultimately providing durable and broad-spectrum protection against diverse influenza virus strains. Full article