Global mortality associated with seasonal influenza epidemics: New burden estimates and predictors from the GLaMOR Project

Analysis of spatial and temporal aggregation of influenza cases in Quzhou before and after COVID-19 pandemic

BACKGROUND

The global seasonal influenza activity has decreased during the coronavirus disease 2019 (COVID-19) pandemic. Non-pharmaceutical interventions (NPIs), such as reducing gatherings and wearing masks, can have varying impacts on the spread of influenza. We aim to analyse the basic characteristics, epidemiology and space-time clustering of influenza in Quzhou city before and after the COVID-19 pandemic based on five years of surveillance data.

METHODS

Influenza case incidence data from 2018-2023 were collected and organized in Quzhou City to analyse the space-time aggregation of influenza incidence before and after COVID-19 pandemic through global spatial autocorrelation analysis and space-time scan analysis methods.

RESULTS

The annual average fluctuation of influenza in Quzhou City from 2018-2023 was large, with gradual decreases in 2019-2020, 2020-2021 and 2021-2022, all of which showed obvious winter and spring peaks; The highest incidence rate in 2022-2023, with a bimodal distribution. The majority of the population is under 15 years of age, accounting for more than 70% of the population. The population classification is dominated by students, nursery children and children in the diaspora. In 2020-2021, the cases in the student group of the 5-14 years old population declined. Global spatial autocorrelation analysis of influenza incidence rate in Quzhou City in each year of 2019-2023Moran's I > 0 and p < 0.05. Space-time scan analysis of the aggregation area is located in Longyou County and the township streets on the border of urban counties, and the number of aggregation areas decreased significantly in 2020-2021 and 2021-2022.

CONCLUSION

The COVID-19 pandemic has an important impact on changes in influenza incidence levels and spatial and temporal epidemiologic aggregation patterns. Influenza incidence in Quzhou City fluctuates widely, with large changes in the age and occupational composition ratios of the incidence population, and influenza incidence presents a more pronounced spatial correlation and aggregation.

Age-related changes in the immune system and challenges for the development of age-specific vaccines

BACKGROUND

A better understanding of how the immune system evolves with age and how vaccines work in older people has led to increasing focus on the development of vaccines aimed specifically at older age groups. We discuss strategies used to improve vaccine immunogenicity for older adults, focusing on licensed adjuvants.

FINDINGS

With age-related immune decline (immunosenescence), older adults face increased vulnerability to infections and severe complications. Immunosenescence affects T-cell and B-cell populations and innate immunity, leading to reduced chemotaxis, cytotoxicity, and altered cytokine production. This contributes to inflammaging-low-grade, chronic inflammation linked to aging. However, immune responses vary due to genetics and life-long exposures, making chronological age an imperfect indicator of immune health. Vaccination remains key to prevention, yet immune dysfunction complicates vaccine efficacy. Strategies to enhance responses in older adults include mRNA vaccines, high-antigen content vaccines, intradermal administration, and adjuvants. mRNA COVID-19 vaccines generated strong immune responses in older adults, though lower than in younger groups. High-antigen content influenza vaccines have shown superior efficacy compared to standard vaccination. Adjuvants offer a well-established approach to boosting vaccine responses by enhancing innate immunity.

CONCLUSIONS

Of various strategies used to improve immunogenicity of vaccines for older adults, adjuvants have been the most consistently effective and practical. More recently, mRNA vaccines have also shown great promise.

Multivalent H3 COBRA-based influenza vaccine elicits enhanced immune response in a pre-immune elderly ferret model

Influenza viruses cause significant mortality in humans, especially among people 65 years and older. The outbreaks of A(H3N2) influenza viruses or viruses of vaccine-mismatched strains are usually associated with more severe diseases in elderly population. Vaccination is the practical countermeasure for controlling influenza virus infection in humans. However, the immune responses elicited by current influenza vaccines in elderly are not as robust as those responses elicited in younger adults. There is an urgent need for a universal influenza virus vaccine that can induce broadly protective immunity against viral infection in elderly individuals. Currently, influenza virus vaccines that target conserved epitopes on a variety of influenza virus antigens are under evaluation. However, almost all these vaccine candidates are evaluated in adult animal models. In this study, we evaluated Computationally Optimized Broadly Reactive Antigen (COBRA)-based influenza vaccines in elderly ferrets with pre-existing immunity to historical influenza viruses to assess the breadth of vaccine induced protective antibody responses. Vaccination of elderly ferrets with Infectimune® adjuvanted mixtures of COBRA hemagglutinin (HA) and neuraminidase (NA) recombinant protein vaccines elicited robust binding antibodies against all components in the vaccine. Vaccine formulations with multiple H3 COBRA HA components significantly enhanced hemagglutination-inhibition (HAI) activity against H3N2 viruses. In addition, elderly ferrets vaccinated with multivalent COBRA HA and NA vaccines were protected from infection with reduced nasal virus shedding. Overall, a multivalent COBRA HA and NA vaccine may be an effective vaccine strategy to reduce morbidity and mortality in the elderly.

Comparing physician and large language model responses to influenza patient questions in the online health community

INTRODUCTION

During influenza season, some patients tend to seek medical advice through online platforms. However, due to time constraints, the informational and emotional support provided by physicians is limited. Large language models (LLMs) can rapidly provide medical knowledge and empathy, but their capacity for providing informational support to patients with influenza and assisting physicians in providing emotional support is unclear. Therefore, this study evaluated the quality of LLM-generated influenza advice and its emotional support performance in comparison with physician advice.

METHODS

This study utilized 200 influenza question-answer pairs from the online health community. Data collection consisted of two parts: (1) A panel of board-certified physicians evaluated the quality of LLM advice vs physician advice. (2) Physician advice was polished using an LLM, and the LLM-rewritten advice was compared to the original physician advice using the LLM module.

RESULTS

For informational support, there was no significant difference between LLM and physician advice in terms of the presence of incorrect information, omission of information, extent of harm or empathy. Nevertheless, compared to physician advice, LLM advice was more likely to cause harm and to be in line with medical consensus. LLM was also able to assist physicians in providing emotional support, since the LLM-rewritten advice was significantly more respectful, friendly and empathetic, when compared with physician advice. Also, the LLM-rewritten advice was logically smooth. In most cases, LLM did not add or omit the original medical information.

CONCLUSION

This study suggests that LLMs can provide informational and emotional support for influenza patients. This may help to alleviate the pressure on physicians and promote physician-patient communication.

Disease Burden of RSV Infection in Adult Patients in Comparison to Influenza Virus Infection

Respiratory Syncytial Virus (RSV) is well known for its impact on children, but its burden in adults remains underexplored, partly due to limited PCR testing before the COVID-19 pandemic. In this study, the medical burden of RSV infections in adults was retrospectively investigated using 6-year longitudinal data from a university hospital in North Rhine-Westphalia, Germany. Outcomes of 380 PCR-confirmed RSV cases were compared with 1088 influenza A/B cases from 2018 to 2023, stratified by age groups ( < 60 and ≥ 60 years). Among RSV cases, 59.7% required hospitalization, of which 22.9% needed oxygen supply. In the whole group hospitalization rates were comparable between RSV and influenza cases, but oxygen supply was more frequent in influenza infections. However, in patients aged ≥ 60 years, no significant differences were observed in hospitalization, oxygen supply, or fatal outcomes between RSV and influenza, indicating a comparable disease burden for both viruses in this group. These findings highlight the significant clinical impact of RSV in adults, particularly those aged ≥ 60 years, paralleling that of influenza. Given influenza's established pathogenic reputation, this underscores the importance of targeted vaccination strategies against RSV, especially for high-risk age groups.

Influenza-Associated Mortality Among Children in Canada from 2004 to 2022

We identified 80 pediatric influenza-associated deaths in Canadian pediatric tertiary hospitals from 2004 to 2022. Children aged <5 years and with high-risk conditions represented 55% and 77.5% of cases, respectively. Only 24.5% of age-eligible hospitalized cases with known vaccination status had been immunized against influenza that season. Vaccination efforts should be enhanced to reduce influenza mortality.

The Impact of Vitamin D in the Prevention of Influenza, COVID-19, and Dengue: A Review

Since its discovery, vitamin D (VD) has been known for its implications in maintaining bone homeostasis. However, in recent years it has been discovered that the vitamin D receptor is expressed on different cells of the immune system and that these cells can locally produce the active form of this molecule, calcitriol, strongly suggesting that this vitamin might play a key role in both branches of the immune system, innate and adaptive. Recent evidence has demonstrated that VD participates in the different protective phases of the immune system against invading microorganisms, including in the activation and production of antimicrobial peptides, in the inactivation of replication of infectious agents, in the prevention of the exposure of cellular receptors to microbial adhesion, and, more importantly, in the modulation of the inflammatory response. In recent years, the world has witnessed major outbreaks of an ancient infectious disease, dengue fever; the emergence of a pandemic caused by an unknown virus, SARS-CoV-2; and the resurgence of a common respiratory infection, influenza. Despite belonging to different viral families, the etiological agents of these infections present a common trait: their capacity to cause complications not only through their cytopathic effect on target tissues but also through the excessive inflammatory response produced by the human host against an infection. This review outlines the current understanding of the role that vitamin D plays in the prevention of the aforementioned diseases and in the development of their complications through its active participation as a major modulator of the immune response.

Airborne Influenza Virus Surveillance Platform Using Paper-Based Immunosensors and a Growth-Based Virus Aerosol Concentrator

The measurement of respiratory viruses in indoor air is critical for effectively preventing the spread of diseases. This is typically accomplished by counting the nucleic acids or plaques of air-sampled viruses. Herein, we present a growth-based airborne virus surveillance (G-AVS) platform based on paper-based electrochemical immunosensors for targeting hemagglutinin (HA) and nucleoprotein (NP), and water-condensation air sampling for the quantitative measurement of airborne influenza viruses. The measurements, compared with RT-qPCR, demonstrated consistency between the two. In the measurements of airborne influenza viruses conducted in an elementary school using G-AVS, 23% (4/17) of indoor air samples were positive, with concentrations ranging from 1.7 × 104 to 1.6 × 106 gene copies/m3, while losses in the HA relative to NP were 48-75% at a relative humidity of 27.0-36.8% and 60 min air sampling, similar to infectivities reported in the literature. This platform has the potential for rapid and cost-effective airborne virus measurement.

Dimensionality reduction for k-means clustering of large-scale influenza mutation datasets

Viral mutations pose significant threats to public health by increasing infectivity, strengthening vaccine resistance, and altering disease severity. To track these evolving patterns, agencies like the CDC annually evaluate thousands of virus strains, underscoring the urgent need to understand viral mutagenesis and evolution in depth. In this study, we integrate genomic analysis, clustering, and three leading dimensionality reduction approaches, namely, principal component analysis (PCA), t-distributed stochastic neighbor embedding (t-SNE), and uniform manifold approximation and projection (UMAP)-to investigate the effects of COVID-19 on influenza virus propagation. By applying these methods to extensive pre- and post-pandemic influenza datasets, we reveal how selective pressures during the pandemic have influenced the diversity of influenza genetics. Our findings indicate that combining robust dimension reduction with clustering yields critical insights into the complex dynamics of viral mutation, informing both future research directions and strategies for public health intervention.

Influenza A virus RNA localisation and the interceding trafficking pathways of the host cell

Viruses have evolved to efficiently navigate host cells to deliver, express, and replicate their genetic material. Understanding the mechanisms underlying viral RNA localisation is paramount to designing new antivirals. In this review, we discuss Influenza A Virus (IAV) as a model system to highlight some of the ways in which RNA viruses can hijack the endomembrane systems, as well as nuclear transporters, to achieve the correct localisation of their transcripts. IAV exemplifies a nuclear-replicating RNA virus with a complex and highly regulated RNA localisation and trafficking system within host cells. The virus subverts various vesicular transport systems and nuclear transporters, altering normal cellular functions. IAV RNA trafficking begins during entry; after clathrin-mediated endocytosis, the viral genome (vRNPs) is released into the cytosol after fusion with the endosomal membrane, and it is subsequently imported into the nucleus via the importin system. There, vRNPs engage with most major subnuclear structures and exploit host chromatin, the transcription machinery and splicing apparatus to achieve efficient viral mRNA synthesis and export. Subsequently, newly synthesised vRNPs are rapidly exported from the nucleus and contact the host's recycling endosome network for transport to the plasma membrane. We discuss the critical viral remodelling of the entire endomembrane system, particularly the Rab11 recycling endosome and the endoplasmic reticulum. Lastly, replicated genomes come together into bundles to be inserted in budding virions, and we discuss the current models being proposed and the evidence behind them. Despite advances in understanding these processes, several knowledge gaps remain, particularly regarding the specific export of unspliced IAV transcripts, the remodelling of the endomembrane system, and segment bundling.

Uncovering the Burden of Influenza-Associated Illness across Levels of Severity in the Kingdom of Saudi Arabia Across Three Seasons

BACKGROUND

Influenza imposes a substantial global health burden, particularly among high-risk populations such as the elderly, young children, and individuals with chronic conditions. In Saudi Arabia, a national influenza sentinel surveillance program was established in 2017 to monitor respiratory virus trends, yet comprehensive estimates of the influenza-associated burden remain limited. This study aims to address this gap by quantifying influenza-associated severe acute respiratory infection (SARI) hospitalization rates and estimating the broader influenza burden across severity levels.

METHODS

Data from four sentinel hospitals in three regions of Saudi Arabia were analyzed across three influenza seasons: 2017-2018, 2018-2019, and 2022-2023. Weekly SARI case counts were combined with census population data to calculate SARI hospitalization rates per 100,000 population. Influenza positivity rates, derived from laboratory-confirmed cases, were used to estimate influenza-associated SARI hospitalization rates, stratified by age and season. The John Hopkins University/WHO Seasonal Influenza Burden Disease Estimator (Flutool) was employed to extrapolate national estimates of influenza-associated hospitalizations, deaths, and mild/moderate cases. Confidence intervals and age-specific stratifications were computed to enhance precision and comparability.

RESULTS

The average annual SARI hospitalization rate was 294 per 100,000 population (95% CI: 288-300). Influenza-associated SARI hospitalization rates averaged 48 per 100,000 population (95% CI: 45-50), with the highest burden observed in individuals aged 65 years and older (269 per 100,000, 95% CI: 240-301) and children aged 0-4 years (118 per 100,000, 95% CI: 107-131). Seasonal variation was noted, with the highest rates in the 2017-2018 season. National estimates suggested a substantial burden, with influenza-associated hospitalizations totaling 17,678 in 2017-2018, 7,683 in 2018-2019, and 13,982 in 2022-2023. The flutool analysis estimated annual influenza-associated deaths ranging from 30 to 4,441 and mild/moderate cases reaching up to 6.3 million in the most severe season.

CONCLUSIONS

This study demonstrates a significant burden of influenza-associated SARI hospitalizations in Saudi Arabia, with the highest rates observed in the elderly and young children. Seasonal variation was evident, highlighting the urgent need to enhance influenza vaccination coverage, particularly among high-risk groups such as the elderly and young children, to reduce severe outcomes. Expanding sentinel surveillance to more regions and incorporating detailed clinical and economic data are recommended to better inform public health policies. Strengthening pandemic preparedness and tailoring vaccination campaigns based on seasonality and age-specific risk will be critical for mitigating the influenza burden in Saudi Arabia.

Application of Humanized MHC Transgenic Mice in the Screening of HLA-Restricted T Cell Epitopes for Influenza Vaccines

BACKGROUND

Annual influenza epidemics pose a significant burden on the global healthcare system. The currently available vaccines mainly induce the production of neutralizing antibodies against hemagglutinin and neuraminidase, which are prone to antigenic variation, and this can reduce vaccine efficacy. Vaccines designed to target T cell epitopes can be potentially valuable. Considering the difficulties in obtaining clinical samples and the unique advantages of mice in disease-related research, a mouse model that can simulate human immune responses can be a superior alternative to peripheral blood mononuclear cells for epitope screening.

METHODS

The T cell epitopes of the A/California/07/2009 (H1N1) virus were predicted and utilized to evaluate the cellular immune responses of HLA-A2/DR1 and HLA-A11/DR1 transgenic mice during epitope screening. The selected peptides were used to immunize these two groups of transgenic mice, followed by a viral challenge to assess their protective efficacy.

RESULTS

The epitopes that were predicted and screened could stimulate cellular immune responses in HLA-A2/DR1 transgenic mice, HLA-A11/DR1 transgenic mice, and C57BL/6 mice. Moreover, the transgenic mice exhibited stronger ability to produce IFN-γ than that of the wild-type mice. Upon immunization and subjecting to viral challenge, the selected peptides exhibited protective effects against the influenza virus.

CONCLUSIONS

The HLA-A2/DR1 and HLA-A11/DR1 transgenic mouse models can be used for the direct screening and validation of influenza virus T cell epitopes, which is crucial for designing T cell epitope vaccines against influenza viruses. Further, this method can be applied in epitope screening and vaccine designing before the spread of other emerging and sudden infectious diseases, thereby supporting epidemic control.

Cost-Effectiveness of Adjuvanted Influenza Vaccine Compared with Standard and High-Dose Influenza Vaccines for Persons Aged ≥50 Years in Spain

BACKGROUND

The prevalence of chronic conditions that increase the risk of influenza complications is high among individuals aged ≥50 years, and evidence suggests age-related changes in immune responses to vaccines begin to decline at this age. Persons aged 50-59 years have high rates of influenza infections and are also the most likely age group to be employed. Thus, the burden of influenza is high in this age group.

METHODS

We investigated the cost-effectiveness of vaccination with an adjuvanted quadrivalent influenza vaccine (aQIV) in a Spanish population aged ≥50 years at high risk of influenza complications. Using a static decision-tree model specifically designed to analyze Spanish data, we calculated incremental cost-effectiveness ratios (ICERs) for aQIV vs. egg-based QIV (QIVe; indicated for any age) and aQIV vs. high-dose QIV (HD-QIV; indicated for persons aged ≥60 years) from payer and societal perspectives. We compared ICERs against a willingness-to-pay threshold of EUR 25,000 per quality-adjusted life year (QALY) gained. The impact of input uncertainty on ICER was evaluated through a probabilistic sensitivity analysis (PSA) and a one-way deterministic sensitivity analysis (DSA).

RESULTS

The total incremental cost of vaccination with aQIV was EUR -86,591,967.67, which was associated with gains of 241.02 in QALY (EUR -359,268.05 per QALY gained) and 318.04 in life years (EUR -272,271.37 per life year gain). Compared with the willingness-to-pay threshold of EUR 25,000 per QALY gained, aQIV was the most cost-effective influenza vaccine relative to the combination of QIVe or HD-QIV. These findings were supported by PSA and DSA analyses.

CONCLUSIONS

In the model, aQIV dominated QIVe and HD-QIV, demonstrating that aQIV use would be cost-saving for persons aged ≥50 years who are at high risk of influenza complications.

Severity Scale of Influenza and Acute Respiratory Illness Hospitalizations to Support Viral Genomic Surveillance: A Global Influenza Hospital Surveillance Network Pilot Study

BACKGROUND

This study aimed to establish a Severity Scale for influenza and other acute respiratory infections (ARI), requiring hospitalization, for surveillance and research purposes (the SevScale). Such a scale could aid the interpretation of data gathered from disparate settings. This could facilitate pooled analyses linking viral genetic sequencing data to clinical severity, bringing insights to inform influenza surveillance and the vaccine strain selection process.

METHODS

We used a subset of data from the Global Influenza Hospital Surveillance Network database, including data from different geographical areas and income levels. To quantify the underlying concept of severity, an item response model was developed using 16 indicators of severity related to the hospital stay. Each patient in the dataset was assigned a Severity Score and a Severity Category (low, medium, or high severity). Finally, we compared the model scores across different subgroups.

RESULTS

Data from 9 countries were included, covering between 4 and 11 seasons from 2012 to 2022, with a total of 96,190 ARI hospitalizations. Not for all severity indicators data were available for all included seasons. Subgroups with a high percentage of patients in the high Severity Category included influenza A(H1N1)pdm09, age ≥ 50, lower-middle income countries, and admission since the start of the COVID-19 pandemic.

CONCLUSIONS

The initial model successfully highlighted severity disparities across patient subgroups. Repeating this exercise with new, more complete data would allow recalibration and validation of the current model. The SevScale proved to be a promising method to define severity for influenza vaccine strain selection, surveillance, and research.

Interactive effects of air pollutants and viral exposure on daily influenza hospital visits in Mongolia

BACKGROUND

Air pollution is a well-documented public health hazard linked to various adverse health outcomes. While studies have shown associations between elevated levels of air pollutants and increased influenza incidence, there is a notable knowledge gap concerning the interactive effects of air pollution and viral exposure on respiratory viral infections.

OBJECTIVES

This study sought to examine the interactive effects of air pollution and viral exposure on influenza hospital visits in Ulaanbaatar, Mongolia.

METHODS

We conducted a time-series analysis linking daily hospital visits for influenza disease (defined as ICD10 diagnosis codes J11) with ambient concentrations of air pollutants (PM1, PM2.5, PM10, NO2, SO2, and O3) over a period of 7 years. Viral exposure for a specific geographical region was estimated based on influenza hospital visits within acute (previous day) and sub-acute (preceding 7 days) exposure windows. Covariates included long-term time trend, temperature, temperature variation, relative humidity, holiday, and raw coal ban policy. An over-dispersed generalized linear model (GLM) with a quasi-Poisson distribution was used to assess associations, exploring interactions and lag effects up to 3 days. Season-specific models and stratified analyses by sex and age were performed, with sensitivity analyses using multi-pollutant models.

RESULTS

A total of 16,364 influenza hospital visits were recorded, with significantly higher rates of visits during the winter season. All six pollutants amplified the effects of viral exposure on hospital visits in cold months, while only PM1, PM2.5, and O3 showed synergistic effects in warm months. Stronger synergistic effects were observed among children under 5 years old, particularly for O3.

CONCLUSIONS

Air pollution significantly amplified the adverse effects of viral exposure on influenza-hospital visits, particularly among young children and during high viral exposure periods. These findings underscore the need for employing protective measures against both air pollution and viral infections.

AI-assisted diagnostic approach for the influenza-like illness in children: decision support system for patients and clinicians

Influenza-like illnesses (ILI), such as influenza and RSV, pose significant global health burdens, especially in febrile children under 6 years old. Differentiating these from bacterial infections based solely on clinical symptoms is challenging. While PCR tests are reliable, they are costly and time-consuming. An effective predictive tool would help doctors prioritize tests and guide parents on seeking emergency care for their febrile children. We collected data from 2,559 children who visited the hospital for ILI inspections. We developed XGBoost models, comparing nine different machine learning algorithms. Our AI-assisted diagnostic pipeline consists of two stages: Decision Support System for patients (DSS-P): An in-house model using sex, age, symptoms, and medical history to decide on hospital visits. Decision Support System for clinicians (DSS-C): An in-hospital model incorporating breath sound types and Chest X-ray results to determine the necessity of clinical tests. We tested various experimental settings, including the addition of RAT-tested samples and the combined consideration of influenza and RSV. The performance for influenza achieved an Area Under the Curve of 0.749 and 0.776, while RSV achieved 0.907 and 0.924 in DSS-P and DSS-C, respectively. We identified biomarkers, noting that most biomarkers had opposite effects for influenza and RSV. This study developed predictive models for influenza and RSV and explored their underlying mechanisms. An expectation tool to guide doctors in prioritizing tests or assisting parents in deciding on emergency care for their febrile child would be invaluable. Biomarker analysis performed can provide insight on clinical fields.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13534-024-00450-8.

Retrospective study on the epidemiological characteristics of multi-pathogen infections of hospitalized severe acute respiratory tract infection and influenza-like illness in Xinjiang from January to May 2024

BACKGROUND

Acute respiratory tract infections are very common and can be caused by many pathogens. The aim of this study was to understand the characteristics of multi-pathogen infections of respiratory tract infections during the seasonal changes in winter and spring in Xinjiang.

METHODS

Throat swab samples were collected from 2791 patients with influenza-like illness (ILI) and hospitalized severe acute respiratory tract infection (SARI) in Xinjiang from January 2024 to May 2024 for multi-pathogen detection. Then, the infection frequency of pathogens and their distribution characteristics in different months, genders, regions and case classifications were analyzed.

RESULTS

The positive infection rate of pathogens in 2791 patients was 48.30% (1348/2791). The proportion of patients infected with respiratory pathogens in the 0-9 age group was the highest. Of all pathogens detected, MP was most common in positive patients (22.03%). The highest frequency of multiple infections was SPn. RSV, FluA and FluB were the main infectious pathogens in January and February. The number of RV, HPIV and MP infections showed an increasing trend from January to May. Compared to female patients, male patients are more likely to be infected with ADV and SPn. Compared with hospitalized SARI patients, outpatient and emergency ILI patients were more susceptible to infection with ADV and FluB. However, hospitalized SARI patients were more susceptible to infection with RSV and MP. The positive infected patients mainly came from northern Xinjiang (60.83%). Compared with other regions, the proportion of ADV positive patients in northern Xinjiang was higher.

CONCLUSION

This study revealed the distribution characteristics of pathogen infection in patients with respiratory tract infections in different months, genders, regions and case classifications during the seasonal changes of winter and spring in Xinjiang for the first time, which is helpful to formulate more effective treatment strategies and preventive measures.

CLINICAL TRIAL NUMBER

not applicable.

Antiviral activity of silver nanoparticles against H1N1 influenza virus

BACKGROUND

Influenza virus is a significant cause of annual global respiratory disease and death. According to the limited availability of effective drugs and vaccines, innovative antivirals are currently being investigated as possible strategies to contain the spread of infectious agents. Among the various types of nanoparticles, silver nanoparticles (Ag-NPs) have attracted great interest due to their exceptional physicochemical properties. This study aims to investigate the antiviral activity of Ag-NPs against the influenza A virus (IAV)/H1N1.

METHODS

The MTT assay was used to determine the possible cytotoxicity of the Ag-NPs. Madin-Darby canine kidney (MDCK) cells were exposed to Ag-NPs extract in conjunction with 100 cell culture infectious dose 50% (CCID50) of virus administered at time intervals during the infection process. The antiviral activity of the extract was evaluated under pre-treatment, post-treatment, and simultaneous assay. Viral titer reduction was assayed using hemagglutination (HA) and CCID50 assays. Viral RNA relative quantification by real-time Polymerase Chain Reaction approach was performed in each experimental condition.

RESULTS

The study yielded significant findings regarding the inhibitory effects of Ag-NPs on the IAV/H1N1. Silver nanoparticles showed dose-dependent inhibition of the virus, with the strongest effect observed when administered simultaneously with the virus which the virus titer exhibited a substantial decrease from 5 Log10 in the control group to 1 Log10 in the initial samples, further reducing to 2 Log10 per milliliter at lower concentrations. Notably, Ag-NPs demonstrated a greater reduction in virus titer during the simultaneous stage, showing a statistically significant difference (P < 0.05) between the control and experimental groups). The reduction in viral titer was also evident in both pre- and post-inoculation stages, although the effects were different.

CONCLUSION

Silver nanoparticles possess inhibitory effects on the growth of the IAV/H1N1, with a significant reduction in virus titer. These findings suggest the potential of Ag-NPs as effective antiviral agents and highlight opportunities for further research and potential clinical applications in combating IAV (H1N1) infections.

Ultrasensitive Specific Detection of Anti-influenza A H1N1 Hemagglutinin Monoclonal Antibody Using Silicon Nanowire Field Effect Biosensors

Rapid and sensitive detection of virus-related antigens and antibodies is crucial for controlling sudden seasonal epidemics and monitoring neutralizing antibody levels after vaccination. However, conventional detection methods still face challenges related to compatibility with rapid, highly sensitive, and compact detection apparatus. In this work, we developed a Si nanowire (SiNW)-based field-effect biosensor by precisely controlling the process conditions to achieve the required electrical properties via complementary metal-oxide-semiconductor (CMOS)-compatible nanofabrication processes. The SiNW surface was chemically modified with 2-aminoethylphosphonic acid, followed by a dehydration condensation reaction with influenza A H1N1 hemagglutinin (HA1), to enable specific detection of anti-HA1 immunoglobulin G (IgG). We successfully detected the anti-influenza IgG with concentrations ranging from 1 aM to 100 nM, achieving a remarkable detection limit of 6.0 aM. To demonstrate specificity, a control experiment was conducted using normal mouse IgG with concentrations of 6 aM to 600 nM. The results showed a high specificity, with the signal being 6-fold greater for the target IgG compared to the control IgG. This work demonstrates the capability of SiNW biosensors to detect anti-influenza A H1N1 hemagglutinin monoclonal antibody with enhanced detection sensitivity and specificity. This work lays the groundwork for future applications in detecting antibodies after vaccination or immunotherapy, contributing to the effective management of infectious pandemics.

Hospitalisation from seasonal influenza among persons with type 1 diabetes: a cohort study from the Swedish National Diabetes Register

OBJECTIVES

The aim of this study was to investigate the risk of severe influenza resulting in hospitalisation among adults with type 1 diabetes (T1D).

DESIGN

Nationwide cohort study using register data.

SETTINGS

Data from the National Diabetes Register (NDR) linked to the Swedish Patient Register, Statistics Sweden and the Swedish Population Register.

PARTICIPANTS

Persons with T1D in the Swedish NDR n=35 596 and control persons from the Swedish Population Register matched on age, sex and county of residence, n=155 590.

PRIMARY AND SECONDARY OUTCOMES

Hospitalisation from seasonal influenza from October 2013 to December 2019. Season-wise incidence and HRs were analysed in the T1D group compared with controls. Secondary outcomes were associations between clinical variables and hospitalisation due to seasonal influenza for persons with T1D.

RESULTS

There were 347 (1.0%) influenza admissions in persons with T1D and 332 (0.2%) in the control group. The overall incidence rate was 16.9/10 000 person-years in the T1D group and 3.6/10 000 person-years for the control group. Persons with T1D had an unadjusted HR 4.7 (95% CI 4.0 to 5.5) for risk of hospitalisation from influenza during the study period and HR 3.4 (95% CI 2.9 to 4.0) when adjusted for age, sex, socioeconomic factors and chronic medical conditions at baseline. Within the T1D cohort, individuals hospitalised due to influenza were older, were more often smokers, had lower glomerular filtration rate and more often had a previous history of ischaemic heart disease and stroke.

CONCLUSIONS

To our knowledge, this is the first large study to highlight that persons with T1D have a threefold higher risk of hospitalisation due to seasonal influenza compared with matched controls from the general population. It is important for healthcare professionals to acknowledge this excess risk, particularly in older persons with T1D, who have cardiovascular risk factors and reduced kidney function.

Are we serologically prepared against an avian influenza pandemic and could seasonal flu vaccines help us?

The current situation with H5N1 highly pathogenic avian influenza virus (HPAI) is causing a worldwide concern due to multiple outbreaks in wild birds, poultry, and mammals. Moreover, multiple zoonotic infections in humans have been reported. Importantly, HPAI H5N1 viruses with genetic markers of adaptation to mammals have been detected. Together with HPAI H5N1, avian influenza viruses H7N9 (high and low pathogenic) stand out due to their high mortality rates in humans. This raises the question of how prepared we are serologically and whether seasonal vaccines are capable of inducing protective immunity against these influenza subtypes. An observational study was conducted in which sera from people born between years 1925-1967, 1968-1977, and 1978-1997 were collected before or after 28 days or 6 months post-vaccination with an inactivated seasonal influenza vaccine. Then, hemagglutination inhibition, viral neutralization, and immunoassays were performed to assess the basal protective immunity of the population as well as the ability of seasonal influenza vaccines to induce protective responses. Our results indicate that subtype-specific serological protection against H5N1 and H7N9 in the representative Spanish population evaluated was limited or nonexistent. However, seasonal vaccination was able to increase the antibody titers to protective levels in a moderate percentage of people, probably due to cross-reactive responses. These findings demonstrate the importance of vaccination and suggest that seasonal influenza vaccines could be used as a first line of defense against an eventual pandemic caused by avian influenza viruses, to be followed immediately by the use of more specific pandemic vaccines.IMPORTANCEInfluenza A viruses (IAV) can infect and replicate in multiple mammalian and avian species. Avian influenza virus (AIV) is a highly contagious viral disease that occurs primarily in poultry and wild water birds. Due to the lack of population immunity in humans and ongoing evolution of AIV, there is a continuing risk that new IAV could emerge and rapidly spread worldwide, causing a pandemic, if the ability to transmit efficiently among humans was gained. The aim of this study is to analyze the basal protection and presence of antibodies against IAV H5N1 and H7N9 subtypes in the population from different ages. Moreover, we have evaluated the humoral response after immunization with a seasonal influenza vaccine. This study is strategically important to evaluate the level of population immunity that is a major factor when assessing the impact that an emerging IAV strain would have, and the role of seasonal vaccines to mitigate the effects of a pandemic.

Safety and Immunogenicity of mRNA-1010, an Investigational Seasonal Influenza Vaccine, in Healthy Adults: Final Results From a Phase 1/2 Randomized Trial

BACKGROUND

Seasonal influenza remains a global public health concern. A messenger RNA (mRNA)-based quadrivalent seasonal influenza vaccine, mRNA-1010, was investigated in a first-in-human, phase 1/2 clinical trial conducted in 3 parts.

METHODS

In parts 1 to 3 of this stratified observer-blind study, adults aged ≥18 years were randomly assigned to receive a single dose (6.25-200 µg) of mRNA-1010 or placebo (part 1) or an active comparator (Afluria; parts 2 and 3). Primary study objectives were assessment of safety, reactogenicity, and humoral immunogenicity of mRNA-1010, placebo (part 1), or active comparator (parts 2 and 3). Exploratory end points included assessment of cellular immunogenicity (part 1) and antigenic breadth against vaccine heterologous strains (A/H3N2; parts 1 and 2).

RESULTS

In all study parts, solicited adverse reactions were reported more frequently for mRNA-1010 than placebo or Afluria, and most were grade 1 or 2 in severity. No vaccine-related serious adverse events or deaths were reported. In parts 1 and 2, a single dose of mRNA-1010 (25-200 µg) elicited robust day 29 hemagglutination inhibition titers that persisted through 6 months. In part 3, lower doses of mRNA-1010 (6.25-25 µg) elicited day 29 hemagglutination inhibition titers that were higher or comparable to those of Afluria for influenza A strains. When compared with Afluria, mRNA-1010 (50 µg) elicited broader A/H3N2 antibody responses (part 2). mRNA-1010 induced greater T-cell responses than placebo at day 8 that were sustained or stronger at day 29 (part 1).

CONCLUSIONS

Data support the continued development of mRNA-1010 as a seasonal influenza vaccine.

CLINICAL TRIALS REGISTRATION

NCT04956575 (https://clinicaltrials.gov/study/NCT04956575).

Antigenic analysis of the influenza B virus hemagglutinin protein

Influenza B viruses (IBVs) primarily infect humans and are a common cause of respiratory infections in humans. Here, to systematically analyze the antigenicity of the IBVs Hemagglutinin (HA) protein, 31 ​B/Victoria and 19 ​B/Yamagata representative circulating strains were selected from Global Initiative of Sharing All Influenza Data (GISAID), and pseudotyped viruses were constructed with the vesicular stomatitis virus system. Guinea pigs were immunized with three doses of vaccines (one dose of DNA vaccines following two doses of pseudotyped virus vaccines) of the seven IBV vaccine strains, and neutralizing antibodies against the pseudotyped viruses were tested. By comparing differences between various vaccine strains, we constructed several pseudotyped viruses that contained various mutations based on vaccine strain BV-21. The vaccine strains showed good neutralization levels against the epidemic virus strains of the same year, with neutralization titers ranging from 370 to 840, while the level of neutralization against viruses prevalent in previous years decreased 1-10-fold. Each of the high-frequency epidemic strains of B/Victoria and B/Yamagata not only induced high neutralizing titers, but also had broadly neutralizing effects against virus strains of different years, with neutralizing titers ranging from 1000 to 7200. R141G, D197 ​N, and R203K were identified as affecting the antigenicity of IBV. These mutation sites provide valuable references for the selection and design of a universal IBV vaccine strain in the future.

Insights into the ecological and climate crisis: Emerging infections threatening human health

The Anthropocene era is marked by unprecedented human-induced alterations to the environment, resulting in a climate emergency and widespread ecological deterioration. A staggering number of up to one million species of plants and animals are in danger of becoming extinct, which includes over 10 % of insect species and 40 % of plant species. Unrestrained release of greenhouse gases, widespread deforestation, intense agricultural practices, excessive fishing, and alterations in land use have exceeded the ecological boundaries that were once responsible for humanity's wellbeing. As per the Intergovernmental Panel on Climate Change (IPCC), existing policies are expected to result in a minimum rise in global temperature of +2 °C, with more recent assessments indicating a potential increase of up to +2.9 °C. The effects of climate change and ecological degradation on the formation of diseases are complex and have multiple aspects. Deforestation diminishes biodiversity and compels wildlife to come into greater proximity with humans, hence promoting the transmission of zoonotic diseases. Climate change intensifies these impacts by modifying the habitats of disease carrying organisms, resulting in the expansion of vector-borne diseases such as malaria, dengue, and Zika virus into previously unaffected areas. Furthermore, climate change amplifies the occurrence and severity of extreme weather phenomena, which undermines water, sanitation, and hygiene (WASH) practices. This creates an environment conducive to the transmission of waterborne diseases such as cholera in densely populated resettlement camps. Climate-induced disasters contribute to the complexity of epidemiological landscapes, exacerbating antimicrobial resistance and posing a threat to modern medical advancements. This narrative review investigates the complex connections between the ecological-climatic crises and emerging illnesses, offering an overview on how environmental changes contribute to outbreaks that pose a substantial threat to public health.

Damage sensing through TLR9 regulates inflammatory and antiviral responses during influenza infection

Host response aimed at eliminating the infecting pathogen, as well as the pathogen itself, can cause tissue injury. Tissue injury leads to the release of a myriad of cellular components including mitochondrial DNA (mtDNA), which the host senses through pattern recognition receptors. How the sensing of tissue injury by the host shapes the anti-pathogen response remains poorly understood. In this study, we utilized mice that are deficient in toll-like receptor-9 (TLR9), which binds to unmethylated CpG DNA sequences such as those present in bacterial and mtDNA. To avoid direct pathogen sensing by TLR9, we utilized the influenza virus, which lacks ligands for TLR9, to determine how damage sensing by TLR9 contributes to anti-influenza immunity. Our data showed that TLR9-mediated sensing of tissue damage promoted an inflammatory response during early infection, driven by epithelial and myeloid cells. Along with the diminished inflammatory response, the absence of TLR9 led to impaired viral clearance manifested as higher and prolonged influenza components in myeloid cells, including monocytes and macrophages, rendering them highly inflammatory. The persistent inflammation driven by infected myeloid cells led to persistent lung injury and impaired recovery in influenza-infected TLR9-/- mice. Further, we found elevated TLR9 ligands in the plasma samples of patients with influenza infection and its association with the disease severity in hospitalized patients, demonstrating its clinical relevance. Overall, we demonstrated an essential role of damage sensing through TLR9 in promoting anti-influenza immunity and inflammatory response. AUTHOR SUMMARY: Tissue damage is an inevitable outcome of clinically relevant lung infections, but the host mechanisms for detecting such damage during infection are not well understood. We investigated the role of Toll-like receptor 9 (TLR9) in sensing tissue damage caused by influenza. Since influenza lacks TLR9 ligands, we hypothesized that TLR9 signaling is driven by tissue damage molecules like mitochondrial DNA (mtDNA). Our data revealed that TLR9 deficiency reduces early inflammatory lung injury but impairs viral clearance, resulting in extensive infection of immune cells, persistent inflammation, and delayed recovery. Myeloid-specific TLR9 deletion ameliorated late-stage inflammatory responses. In humans, influenza-infected individuals exhibited elevated TLR9 activity and mtDNA levels in plasma compared to healthy controls, with higher TLR9 activation potential correlating with severe disease requiring ICU admission. These findings suggest that TLR9-mediated damage sensing triggers both inflammatory tissue injury and viral clearance. These data indicate that TLR9 activity can serve as a crucial biomarker and therapeutic target to limit influenza-induced tissue injury.

Respiratory virus detections in children presenting to an Australian paediatric referral hospital pre-COVID-19 pandemic, January 2014 to December 2019

Acute respiratory infections cause significant paediatric morbidity, but for pathogens other than influenza, respiratory syncytial virus (RSV), and SARS-CoV-2, systematic monitoring is not commonly performed. This retrospective analysis of six years of routinely collected respiratory pathogen multiplex PCR testing at a major paediatric hospital in New South Wales Australia, describes the epidemiology, year-round seasonality, and co-detection patterns of 15 viral respiratory pathogens. 32,599 respiratory samples from children aged under 16 years were analysed. Most samples were associated with a hospital admission (24,149, 74.1%) and the median age of sampling was 16 months (IQR 5-53). Viruses were detected in 62.9% (20,510) of samples, with single virus detections occurring in 73.5% (15,082) of positive samples. In instances of single virus detection, rhinovirus was most frequent (5125, 40.6%), followed by RSV-B (1394, 9.2%) and RSV-A (1290, 8.6%). Moderate to strong seasonal strength was observed for most viruses with some notable exceptions. Rhinovirus and enterovirus were detected year-round and low seasonal strength was observed for adenovirus and bocavirus. Biennial seasonal patterns were observed for influenza B and parainfluenza virus 2. Co-detections occurred in 5,428 samples, predominantly with two (4284, 79.0%) or three viruses (904, 16.7%). The most common co-detections were rhinovirus-adenovirus (566, 10.4%), rhinovirus-enterovirus (357, 8.3%), and rhinovirus-RSV-B (337, 7.9%). Ongoing pan-pathogen surveillance, integrating both laboratory and clinical data, is necessary to assist in identification of key pathogens and combination of pathogens to support effective preventative public health strategies and reduce the burden of paediatric respiratory infections.

Obesity Is a Risk Factor for Severe Influenza Virus Infection and COVID-19 in Children

During influenza A virus or severe acute respiratory syndrome coronavirus 2 infection in adults, obesity is an independent risk factor for severe disease. In children, evidence is less clear. Research is needed to elucidate the mechanisms underpinning any association between obesity and severe respiratory viral infections in children.

Effects of fine particulate matter and its chemical constituents on influenza-like illness in Guangzhou, China

BACKGROUND

Although the link between fine particulate matter (PM2.5) and influenza-like illness (ILI) is well established, the effect of the chemical constituents of PM2.5 on ILI remains unclear. This study aims to explore this effect in Guangzhou, China.

METHODS

Daily data on ILI cases, PM2.5 levels, and specific PM2.5 constituents (black carbon [BC], chlorine [Cl-], ammonia [NH4+], nitrate [NO3-], and sulfate [SO42-]) in Guangzhou, China, were collected for the period of 2014-2019. Additionally, data on gaseous pollutants and meteorological conditions were obtained. By using quasi-Poisson regression models, the association between exposure to PM2.5 and its constituents and ILI risk was estimated. Stratified subgroup analyses were performed by gender, age, and season to explore in depth the effects of these factors on disease risk.

RESULTS

Single-pollutant modeling results showed that an increase of one interquartile range (IQR) in Cl-, SO42-, PM2.5, NH4+, BC, and NO3- corresponded to relative risks of ILI of 1.046 (95 % CI: 1.004, 1.090) (lag03), 1.098 (95 % CI: 1.058, 1.139) (lag01), 1.091 (95 % CI: 1.054, 1.130) (lag02), 1.093 (95 % CI: 1.049, 1.138) (lag02), 1.111 (95 % CI: 1.074, 1.150) (lag03), and 1.103 (95 % CI: 1.061, 1.146) (lag03), respectively. Notably, the association between ILI and BC remained significant even after adjusting for PM2.5 mass. Subgroup analyses indicated that individuals aged 5-14 and 15-24 years may exhibit higher sensitivity to BC and Cl- exposure than other individuals. Furthermore, stronger associations were observed during the cold season than during the warm season.

CONCLUSIONS

Results showed that the mass and constituents of PM2.5 were significantly correlated with ILI. Specifically, the carbonaceous fractions of PM2.5 were found to have a pronounced effect on ILI. These findings underscore the importance of implementing effective measures to reduce the emission of specific sources of PM2.5 constituents to mitigate the risk of ILI. Nevertheless, limitations such as potential exposure misclassification and regional constraints should be considered.

Galectin-3 disrupts tight junctions of airway epithelial cell monolayers by inducing expression and release of matrix metalloproteinases upon influenza A infection

Galectins are β-galactosyl-binding lectins with key roles in early development, immune regulation, and infectious disease. Influenza A virus (IAV) infects the airway epithelia, and in severe cases may lead to bacterial superinfections and hypercytokinemia, and eventually, to acute respiratory distress syndrome (ARDS) through the breakdown of airway barriers. The detailed mechanisms involved, however, remain poorly understood. Our prior in vivo studies in a murine model system revealed that upon experimental IAV and pneumococcal primary and secondary challenges, respectively, galectin-1 and galectin-3 (Gal-3) are released into the airway and bind to the epithelium that has been desialylated by the viral neuraminidase, contributing to secondary bacterial infection and hypercytokinemia leading to the clinical decline and death of the animals. Here we report the results of in vitro studies that reveal the role of the extracellular Gal-3 in additional detrimental effects on the host by disrupting the integrity of the airway epithelial barrier. IAV infection of the human airway epithelia cell line A549 increased release of Gal-3 and its binding to the A549 desialylated cell surface, notably to the transmembrane signaling receptors CD147 and integrin-β1. Addition of recombinant Gal-3 to A549 monolayers resulted in enhanced expression and release of matrix metalloproteinases, leading to disruption of cell-cell tight junctions, and a significant increase in paracellular permeability. This study reveals a critical mechanism involving Gal-3 that may significantly contribute to the severity of IAV infections by promoting disruption of tight junctions and enhanced permeability of the airway epithelia, potentially leading to lung edema and ARDS.

Safety and immunogenicity of mRNA-based seasonal influenza vaccines formulated to include multiple A/H3N2 strains with or without the B/Yamagata strain in US adults aged 50-75 years: a phase 1/2, open-label, randomised trial

BACKGROUND

Inclusion of additional influenza A/H3N2 strains in seasonal influenza vaccines could expand coverage against multiple, antigenically distinct, cocirculating A/H3N2 clades and potentially replace the no longer circulating B/Yamagata strain. We aimed to evaluate the safety and immunogenicity of three next-generation seasonal influenza mRNA vaccines with different compositions that encode for haemagglutinins of multiple A/H3N2 strains, with or without the B/Yamagata strain, in adults.

METHODS

This randomised, open-label, phase 1/2 trial enrolled healthy adults aged 50-75 years across 22 sites in the USA. Participants were randomly assigned (1:1:1:1:1:1:1) via interactive response technology to receive a single dose of mRNA-1011.1 (pentavalent; containing one additional A/H3N2 strain [Newcastle]), mRNA-1011.2 (quadrivalent; B/Yamagata replaced with one additional A/H3N2 strain [Newcastle]), mRNA-1012 at one of two dose levels (pentavalent; B/Yamagata replaced with two additional A/H3N2 strains [Newcastle and Hong Kong]), or one of three quadrivalent mRNA-1010 controls each encoding one of the A/H3N2 study strains. The primary outcomes were safety, evaluated in all randomly assigned participants who received a study vaccination (safety population), and reactogenicity, evaluated in all participants from the safety population who contributed any solicited adverse reaction data (solicited safety population). The secondary outcome was humoral immunogenicity of investigational mRNA vaccines at day 29 versus mRNA-1010 control vaccines based on haemagglutination inhibition antibody (HAI) assay in the per-protocol population. Here, we summarise findings from the planned interim analysis after participants had completed day 29. The study is registered with ClinicalTrials.gov, NCT05827068, and is ongoing.

FINDINGS

Between March 27 and May 9, 2023, 1183 participants were screened for eligibility, 699 (59·1%) were randomly assigned, and 696 (58·8%) received vaccination (safety population, n=696; solicited safety population, n=694; per-protocol population, n=646). 382 (55%) of the 696 participants in the safety population self-reported as female and 314 (45%) as male. Frequencies of solicited adverse reactions were similar across vaccine groups; 551 (79%) of 694 participants reported at least one solicited adverse reaction within 7 days after vaccination and 83 (12%) of 696 participants reported at least one unsolicited adverse event within 28 days after vaccination. No vaccine-related serious adverse events or deaths were reported. All three next-generation influenza vaccines elicited robust antibody responses against vaccine-matched influenza A and B strains at day 29 that were generally similar to mRNA-1010 controls, and higher responses against additional A/H3N2 strains that were not included within respective mRNA-1010 controls. Day 29 geometric mean fold rises in HAI titres from day 1 against vaccine-matched A/H3N2 strains were 3·0 (95% CI 2·6-3·6; Darwin) and 3·1 (2·6-3·8; Newcastle) for mRNA-1011.1; 3·3 (2·7-4·1; Darwin) and 4·2 (3·4-5·2; Newcastle) for mRNA-1011.2; 3·4 (2·9-4·0; Darwin), 4·5 (3·6-5·5; Newcastle), and 5·1 (4·2-6·2; Hong Kong) for mRNA-1012 50·0 μg; and 2·6 (2·2-3·1; Darwin), 3·7 (3·0-4·6; Newcastle), and 4·1 (3·3-5·1; Hong Kong) for mRNA-1012 62·5 μg. Inclusion of additional A/H3N2 strains did not reduce responses against influenza A/H1N1 or influenza B strains, and removal of B/Yamagata did not affect responses to B/Victoria.

INTERPRETATION

These data support the continued clinical development of mRNA-based next-generation seasonal influenza vaccines with broadened influenza A/H3N2 strain coverage.

FUNDING

Moderna.

Administration of antigenically distinct influenza viral particle combinations as an influenza vaccine strategy

One approach for developing a more universal influenza vaccine is to elicit strong immune responses against canonically immunosubdominant epitopes in the surface exposed viral glycoproteins. While standard vaccines typically induce responses directed primarily against mutable epitopes in the hemagglutinin (HA) head domain, there are generally limited or variable responses directed against epitopes in the relatively more conserved HA stalk domain and neuraminidase (NA) proteins. Here we describe a vaccine approach that utilizes a combination of wildtype (WT) influenza virus particles along with virus particles engineered to display a trimerized HA stalk in place of the full-length HA protein to elicit both responses simultaneously. After initially generating the "headless" HA-containing viral particles in the A/Hawaii/70/2019 (HI/19) genetic background and demonstrating the ability to elicit protective immune responses directed against the HA-stalk and NA, we co-formulated those virions with unmodified WT viral particles. The combination vaccine elicited "hybrid" and protective responses directed against the HA-head, HA-stalk, and NA proteins in both naïve and pre-immune mice and ferrets. Collectively, our results highlight a potentially generalizable method combining viral particles with differential antigenic compositions to elicit broader immune responses that may lead to more durable protection from influenza disease post-vaccination.

Evaluation of the Seegene Allplex™ RV master assay for one-step simultaneous detection of eight respiratory viruses in nasopharyngeal specimens

BACKGROUND

The Seegene Allplex™ RV Master (RVM) assay is a one-step multiplex real-time reverse transcription polymerase chain reaction (RT-PCR) system for detecting eight viral respiratory pathogens from nasopharyngeal swab, aspirate, and bronchoalveolar lavage specimens. The eight RVM targets are: severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), Influenza A (Flu A), Influenza B (Flu B), Human respiratory syncytial virus (RSV), adenovirus (AdV), rhinovirus (HRV), parainfluenza virus (PIV), and metapneumovirus (MPV). The assay is based on Seegene's multiple detection temperature (MuDT) technology and provides cycle threshold (Ct) values for each of its viral targets upon PCR completion.

OBJECTIVE

We aimed to evaluate the diagnostic performance of the RVM assay by calculating sensitivity, specificity, accuracy, Positive Predictive Value (PPV), Negative Predictive Value (NPV), Positive Percent Agreement (PPA), Negative Percent Agreement (NPA), and Overall Percent Agreement (OPA) compared to definite diagnosis and analogous reference assays.

STUDY DESIGN

Diagnostic sensitivity, specificity, accuracy, PPV, and NPV were calculated by comparing the results of the RVM assay to that of definite diagnosis assays; while PPA, NPA, and OPA were calculated by comparing results of the RVM assay to that of analogous reference products. Definite diagnosis and reference methods comprised whole genome sequencing and PCR genotyping, the Allplex™ SARS-CoV-2/FluA/FluB/RSV and Respiratory Panels 1, 2, and 3 assays (Seegene), and the Xpert® Xpress SARS-CoV-2/FluA/FluB/RSV Plus assay (Cepheid). Reproducibility of the RVM assay using fully-automated and semi-automated nucleic acid (NA) extraction workflows and as performed by independent operators was also assessed. In total, 249 positive respiratory specimens and at least 50 negative specimens for each target tested were used for this evaluation study.

RESULTS

Sensitivity, specificity, accuracy, PPV, NPV, PPA, NPA, and OPA ranged from 95.7 % to 100 % for detecting all eight targets tested on the RVM assay. Reproducibility PPA, NPA, and OPA between automated and semi-automated NA extraction workflows were all >97.9 %, while the reproducibility PPA, NPA and OPA between independent operators were all 100 %.

CONCLUSION

These results demonstrate a high level of sensitivity, specificity, accuracy and diagnostic predictive value of the RVM assay and high agreement with comparable reference assays in identifying all eight of its targets. Taken together, our study underscores the diagnostic utility of the RVM assay in detecting eight viral respiratory pathogens.

The burden, pathogenesis, clinical outcomes, and treatment of common respiratory virus infections during pregnancy

Respiratory illnesses due to respiratory virus infections disproportionately impact pregnant individuals and their infants, leading to significant morbidity and mortality globally. Data describing the incidence and impact of these infections in pregnancy is sparse and more common for influenza and now severe acute respiratory syndrome coronavirus 2 with less data available on other respiratory virus infections in pregnancy. This lack of data is a result of limited prospective surveillance and issues surrounding the calculations of seroprevalence, as well as disproportionately low funding for reproductive health research. In this review article, we aimed to summarize available data on respiratory virus infections in pregnancy and identify gaps in the published literature.

Burden of Acute Respiratory Infections Caused by Influenza Virus, Respiratory Syncytial Virus, and SARS-CoV-2 with Consideration of Older Adults: A Narrative Review

Influenza virus, respiratory syncytial virus (RSV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are acute respiratory infections (ARIs) that can cause substantial morbidity and mortality among at-risk individuals, including older adults. In this narrative review, we summarize themes identified in the literature regarding the epidemiology, seasonality, immunity after infection, clinical presentation, and transmission for these ARIs, along with the impact of the COVID-19 pandemic on seasonal patterns of influenza and RSV infections, with consideration of data specific to older adults when available. As the older adult population increases globally, it is of paramount importance to fully characterize the true disease burden of ARIs in order to develop appropriate mitigation strategies to minimize their impact in vulnerable populations. Challenges associated with characterizing the burden of these diseases include the shared symptomology and clinical presentation of influenza virus, RSV, and SARS-CoV-2, which complicate accurate diagnosis and highlight the need for improved testing and surveillance practices. To this end, multiple regional, national, and global virologic and disease surveillance systems have been established to provide accurate knowledge of viral epidemiology, support appropriate preparedness and response to potential outbreaks, and help inform prevention strategies to reduce disease severity and transmission. Beyond the burden of acute illness, long-term health consequences can also result from influenza virus, RSV, and SARS-CoV-2 infection. These include cardiovascular and pulmonary complications, worsening of existing chronic conditions, increased frailty, and reduced life expectancy. ARIs among older adults can also place a substantial financial burden on society and healthcare systems. Collectively, the existing data indicate that influenza virus, RSV, and SARS-CoV-2 infections in older adults present a substantial global health challenge, underscoring the need for interventions to improve health outcomes and reduce the disease burden of respiratory illnesses.Graphical abstract and video abstract available for this article.

Neutralization potency of the 2023-24 seasonal influenza vaccine against circulating influenza H3N2 strains

Seasonal influenza is a severe disease that significantly impacts public health, causing millions of infections and hundreds of thousands of deaths each year. Seasonal influenza viruses, particularly the H3N2 subtype, exhibit high antigenic variability, often leading to mismatch between vaccine strains and circulating strains. Therefore, rapidly assessing the alignment between existing seasonal influenza vaccine and circulating strains is crucial for enhancing vaccine efficacy. This study, based on a pseudovirus platform, evaluated the match between current influenza H3N2 vaccine strains and circulating strains through cross-neutralization assays using clinical human immune sera against globally circulating influenza virus strains. The research results show that although mutations are present in the circulating strains, the current H3N2 vaccine strain still imparting effective protection, providing a scientific basis for encouraging influenza vaccination. This research methodology can be sustainably applied for the neutralization potency assessment of subsequent circulating strains, establishing a persistent methodological framework.

A cross-sectional study on the understanding and attitudes toward influenza and influenza vaccines among different occupational groups in China

This study aimed to assess the level of knowledge regarding influenza viruses and vaccines among different professional groups to investigate the reasons for vaccine hesitancy. We collected 2190 questionnaires regarding influenza vaccines in China in 2022. The respondents were categorized into the general population (GP), foreign affairs workforce population (FAWP), and veterinary workforce population (VWP) according to their job positions. Linear regression was used to assess the association between multiple factors and influenza vaccination rates. The association between work and influenza vaccination rates was also assessed by grouping different workforce populations. The vaccination rate of the GP was higher than that of the VWP (odds ratio: 1.342, 95% confidence interval: 1.025-1.853), surpassing the rates reported in previous studies. This may be attributed to heightened concerns about infectious diseases influenced by the ongoing coronavirus disease 2019 pandemic. Despite the VWP's more in-depth knowledge of the VWP on zoonotic diseases and their recognition of their importance, there was no significant difference in influenza knowledge among the three populations. This discrepancy contrasts with the observed differences in vaccination rates. Further investigation revealed that, compared with FAWP, the price of vaccines emerged as a primary influencing factor for vaccination rates (odds ratio:0.398, 95%CI; 0.280-0.564). General concerns regarding the protective effects and side effects of vaccines were also noted.

COBRA N2 NA vaccines induce protective immune responses against influenza viral infection

Influenza neuraminidase (NA) is a promising target for a broadly protective vaccine. In this study, the Computationally Optimized Broadly Reactive Antigen (COBRA) methodology was used to develop N2 NA vaccine candidates. The unique wild type (WT) N2 sequences of human and swine influenza strains isolated between 1957 and 2019 were used to design the COBRA N2-A NA vaccine, while the unique WT N2 sequences of human influenza strains isolated between 2000 and 2019 were used to design the COBRA N2-B NA vaccine. Sera collected from COBRA N2 NA vaccinated mice showed more broadly reactive antibody responses against a broad panel of H×N2 influenza virus strains than sera collected from mice vaccinated with WT N2 NA vaccines. Antibodies elicited by COBRA or WT N2 NA antigens cross react with recent human H3N2 influenza viruses from different clades, while the antibodies elicited by A/Switzerland/9715293/2013 hemagglutinin (HA) reacted with viruses from the same clade. Furthermore, mice vaccinated with COBRA N2-B NA vaccine had lower viral lung titers compared to mock vaccinated mice when challenged with human H3N2 influenza viruses. Thus, the COBRA N2 NA vaccines elicit broadly protective murine anti-NA antibodies against multiple strains across subtypes and the viral loads were significantly decreased in the lungs of the mice in the COBRA N2 NA vaccine groups, compared to the mice in the mock vaccinated group, indicating that the COBRA-based N2 subtype NA vaccines have a potential to be a component in a universal influenza vaccine.

Impact of COVID-19 pandemic on influenza vaccination rate among health care workers

Vaccinations against influenza are critical in mitigating the severity of the disease, preventing its transmission, and restricting its dissemination. Concerns about vaccination hesitancy among healthcare workers (HCWs) have been duly recognized during and following the COVID-19 pandemic. To examine the extent to which the COVID-19 pandemic has influenced the adoption of vaccinations among HCWs. A cross-sectional online survey was conducted four years after the COVID-19 pandemic among HCWs in Saudi Arabia. We performed a logistic regression analysis using influenza vaccination uptake as the dependent variable and perceived COVID-19 pandemic's impact, age, gender, marital status, employment status, education level, monthly income, respondent's overall health, doctor visits, tobacco use, number of adults in the household, and number of children in the household as independent variables. The study included 574 participants, an 86% response rate. Of the sample, 47% reported they had the influenza vaccination. HCWs who reported a greater negative impact due to the COVID-19 pandemic were 40% more likely to acquire the influenza vaccine (OR = 1.4, 95% CI [1.24, 1.58]). Compared to HCWs without children, HCWs with a child had a 44% lower likelihood of taking the influenza vaccination (OR = 0.34, 95% CI [0.16, 0.69]). The odds of HCWs obtaining the influenza vaccine were 4.5 times higher for those who reported one yearly medical visit, 2.6 times higher for two, and 1.4 times higher for three or more. HCWs who experienced more severe COVID-19 outcomes were more likely to get vaccinated against the virus. However, long-term monitoring of this inclination is necessary.

The conserved protein DopA is required for growth, drug tolerance and virulence in Aspergillus fumigatus

The majority of Aspergillus fumigatus reproduction occurs asexually, with large numbers of conidiophores producing small hydrophobic conidia dispersed aerially. When healthy hosts inhale conidia, the mucosal cilia and phagocytosis by the innate immune system can remove them. However, in immunocompromised hosts, the conidia are not removed, which allows them to germinate, forming mycelium that invades host tissues and causes disease. Previously we isolated a white A. fumigatus A1j strain incapable of producing conidia and screened several genes (including dopA) with significant expression differences and mutant loci in A1j. DopA homologous proteins in other species have been partially studied and are known to participate in various membrane transport-related cellular functions. Defects in these proteins in Saccharomyces cerevisiae, Caenorhabditis elegans, and Aspergillus nidulans result in defective cell morphology and abnormal growth. In this study, we observed reduced conidia production and abnormal development of spore-producing structures in the A. fumigatus dopA null strain, compared to parental strain, and demonstrated that dopA also modulates stress response and virulence of A. fumigatus.

Intranasal influenza-vectored vaccine expressing pneumococcal surface protein A protects against Influenza and Streptococcus pneumoniae infections

Streptococcus pneumoniae and influenza A virus (IAV) are significant agents of pneumonia cases and severe respiratory infections globally. Secondary bacterial infections, particularly by Streptococcus pneumoniae, are common in IAV-infected individuals, leading to critical outcomes. Despite reducing mortality, pneumococcal vaccines have high production costs and are serotype specific. The emergence of new circulating serotypes has led to the search for new prevention strategies that provide a broad spectrum of protection. In this context, vaccination using antigens present in all serotypes, such as Pneumococcal Surface Protein A (PspA), can offer broad coverage regardless of serotype. Employing the reverse genetics technique, our research group developed a recombinant influenza A H1N1 virus that expresses PspA (Flu-PspA), through the replacement of neuraminidase by PspA. This virus was evaluated as a bivalent vaccine against infections caused by influenza A and S. pneumoniae in mice. Initially, we evaluated the Flu-PspA virus's ability to infect cells and express PspA in vitro, its capacity to multiply in embryonated chicken eggs, and its safety when inoculated in mice. Subsequently, the protective effect against influenza A and Streptococcus pneumoniae lethal challenge infections in mice was assessed using different immunization protocols. Analysis of the production of antibodies against PspA4 protein and influenza, and the binding capacity of anti-PspA4 antibodies/complement deposition to different strains of S. pneumoniae were also evaluated. Our results demonstrate that the Flu-PspA virus vaccine efficiently induces PspA protein expression in vitro, and that it was able to multiply in embryonated chicken eggs even without exogenous neuraminidase. The Flu-PspA-based bivalent vaccine was demonstrated to be safe, stimulated high titers of anti-PspA and anti-influenza antibodies, and protected mice against homosubtypic and heterosubtypic influenza A and S. pneumoniae challenge. Moreover, an efficient binding of antibodies and complement deposition on the surface of pneumococcal strains ascribes the broad-spectrum vaccine response in vivo. In summary, this innovative approach holds promise for developing a dual-protective vaccine against two major respiratory pathogens.

An evaluation of the National Influenza Vaccination Program in the Republic of Moldova, 2023-2024

During the 2023-2024 influenza season, the Republic of Moldova, a lower-middle income country seeking accession into the European Union, independently financed their influenza vaccine supply transitioning from external support from the Partnership for International Vaccine Initiatives, a collaboration conceived in 2015. As part of this transition, a mixed-methods evaluation was conducted from May 2023 - January 2024 to identify current strengths and weaknesses of the influenza vaccination program. A total of 157 interviews were conducted: one with the National Immunization Program (NIP), six with district health officers, 18 at health facilities, 18 with caregivers/parents, 34 with healthcare workers, 43 with adults with chronic diseases, 19 with pregnant women, and 13 vaccine observation sessions; further five expert interviews with an international organization, the insurance company, senior government officials in public health and within the ministry of health, and those involved with COVID-19 were conducted. The Republic of Moldova's NIP has benefited from decades of experience, internal commitments to progress, and contributions from external partners. Despite this progress, the evaluation recognized four areas for improvement. Recommendations from the evaluation assessment included: 1) develop a national strategy for immunization, including the establishment of national goals in consultation with the national immunization technical advisory group (NITAG); 2) expand immunization communications and advocacy initiatives, particularly to adults and pregnant individuals; 3) leverage trusted patient-doctor relationships and encourage vaccination as a healthcare norm with physician specialists; and 4) conduct operations research to better understand vaccine hesitancy in populations such as pregnant individuals. Additional thematic findings emphasized the importance of ensuring timely receipt of vaccine doses into the country no later than September, as medical providers reported difficulty administering doses when vaccines were delivered after September. Our findings outline ways to further strengthen the Republic of Moldova's self-sustained annual influenza vaccination program.

Unraveling influenza sentinel surveillance in Pakistan 2008-2024: Epidemiological insights during the pre and post pandemic period of COVID-19

BACKGROUND

The coronavirus pandemic has substantially influenced the transmission pattern of other respiratory viruses. However, screening and detecting other respiratory pathogens was unheeded during this time to combat the COVID-19 pandemic. High virulence and re assortment factors intensify the importance of influenza virus surveillance for effective disease management. Therefore, the present surveillance study was designed to determine the influenza positivity rate from 2008-24. This study will provide integral support in depicting a panoramic representation of two respiratory-pandemic periods, 2010-11 and 2019-2021, for influenza and COVID-19 pandemics, respectively.

METHODS

An inferential cross-sectional study was conducted from 2008 to 2024 by collecting influenza surveillance data from twelve sentinel sites in Pakistan. Clinical and demographic data was recorded at sample collection time. Specimens were collected through nasopharyngeal/throat swabs and stored in viral transport medium (VTM) at the sentinel site laboratory at 2-4 °C. Viral RNA was isolated from the samples using KingFisher TM Flex Purification System and MagMAX™ Viral/Pathogen Nucleic Acid Extraction Kit.

RESULTS

Within 16 years, 78118 samples were tested for influenza, of which 7999 (10.2 %) appeared positive. The positivity rate appeared very low in recent years, with only a 3.5 % positivity rate observed in 2020. Influenza A strain H1N1pdm09 seemed to be the prominent strain (n = 3407, 42.6 %), followed by influenza B (n = 2125, 26.6 %).

CONCLUSION

The positivity of influenza samples was 10.2 % and recorded in patients where typical clinical representation of influenza was absent. Fewer samples were reported during the coronavirus pandemic, which might be because influenza screening was hindered and overlooked to combat the SARS-CoV-2 virus, and the patient threshold was very high for COVID-19 virus screening.

Comprehensive molecular epidemiology of influenza viruses in Brazil: insights from a nationwide analysis

Influenza A and B viruses represent significant global health threats, contributing substantially to morbidity and mortality rates. However, a comprehensive understanding of the molecular epidemiology of these viruses in Brazil, a continental-size country and a crucial hub for the entry, circulation, and dissemination of influenza viruses within South America, still needs to be improved. This study addresses this gap by consolidating data and samples across all Brazilian macroregions, as part of the Center for Viral Surveillance and Serological Assessment project, together with an extensive number of other Brazilian sequences provided by a public database during the epidemic seasons spanning 2021-23. Phylogenetic analysis of the hemagglutinin segment of influenza A/H1N1pdm09, A/H3N2, and influenza B/Victoria-lineage viruses revealed that in 2021 and in the first semester of 2022, the A/H3N2 2a.3 strain was the predominant circulating strain. Subsequently, the A/H3N2 2b became the prevalent strain until October, when it was substituted by A/H1N1pdm09 5a.2a and 5a.2a.1 lineages. This scenario was maintained during the year of 2023. B/Victoria emerged and circulated at low levels between December 2021 and September 2022 and then became coprevalent with A/H1N1pdm09 5a.2a and 5a.2a.1 lineages. The comparison between the vaccine strain A/Darwin/9/2021 and circulating viruses revealed shared mutations to aspartic acid at residues 186 and 225 across all A/H3N2 lineages from 2021 to 2023, altering the charge in the receptor-binding domain. For A/H1N1pdm09, the 2022 consensus of 5a.2a.1 and the vaccine strain A/Victoria/2570/2019 showed 14 amino acid substitutions. Key residues H180, D187, K219, R223, E224, and T133 are involved in hydrogen interactions with sialic acids, while N130, K142, and D222 may contribute to distance interactions based on docking analyses. Importantly, distinct influenza A lineage frequency patterns were observed across Brazil's macroregions, underscoring the regional variations in virus circulation. This study characterizes influenza A and B viruses circulating in Brazil, providing insights into their circulation patterns and dynamics across Brazilian macroregions. These findings hold significant implications for public health interventions, informing strategies to mitigate transmission risks, optimize vaccination efforts, and enhance outbreak control measures.

Profiling Bacteria in the Lungs of Patients with Severe Influenza Versus COVID-19 with or without Aspergillosis

Rationale: The influence of the lung bacterial microbiome, including potential pathogens, in patients with influenza-associated pulmonary aspergillosis (IAPA) or coronavirus disease (COVID-19)-associated pulmonary aspergillosis (CAPA) has yet to be explored. Objectives: To explore the composition of the lung bacterial microbiome and its association with viral and fungal infection, immunity, and outcome in severe influenza versus COVID-19 with or without aspergillosis. Methods: We performed a retrospective study in mechanically ventilated patients with influenza and COVID-19 with or without invasive aspergillosis in whom BAL for bacterial culture (with or without PCR) was obtained within 2 weeks after ICU admission. In addition, 16S rRNA gene sequencing data and viral and bacterial load of BAL samples from a subset of these patients, and of patients requiring noninvasive ventilation, were analyzed. We integrated 16S rRNA gene sequencing data with existing immune parameter datasets. Measurements and Main Results: Potential bacterial pathogens were detected in 20% (28/142) of patients with influenza and 37% (104/281) of patients with COVID-19, whereas aspergillosis was detected in 38% (54/142) of patients with influenza and 31% (86/281) of patients with COVID-19. A significant association between bacterial pathogens in BAL fluid and 90-day mortality was found only in patients with influenza, particularly patients with IAPA. Patients with COVID-19, but not patients with influenza, showed increased proinflammatory pulmonary cytokine responses to bacterial pathogens. Conclusions: Aspergillosis is more frequently detected in the lungs of patients with severe influenza than bacterial pathogens. Detection of bacterial pathogens associates with worse outcome in patients with influenza, particularly in those with IAPA, but not in patients with COVID-19. The immunological dynamics of tripartite viral-fungal-bacterial interactions deserve further investigation.

Age-related STING suppression in macrophages contributes to increased viral load during influenza a virus infection

Ageing is a major risk factor that contributes to increased mortality and morbidity rates during influenza A virus (IAV) infections. Macrophages are crucial players in the defense against viral infections and display impaired function during ageing. However, the impact of ageing on macrophage function in response to an IAV infection remains unclear and offers potential insight for underlying mechanisms. In this study, we investigated the immune response of young and aged human monocyte-derived macrophages to two different H1N1 IAV strains. Interestingly, macrophages of aged individuals showed a lower interferon response to IAV infection, resulting in increased viral load. Transcriptomic data revealed a reduced expression of stimulator of interferon genes (STING) in aged macrophages albeit the cGAS-STING pathway was upregulated. Our data clearly indicate the importance of STING signaling for interferon production by applying a THP-1 STING knockout model. Evaluation of mitochondrial function during IAV infection revealed the release of mitochondrial DNA to be the activator of cGAS-STING pathway. The subsequent induction of apoptosis was attenuated in aged macrophages due to decreased STING signaling. Our study provides new insights into molecular mechanisms underlying age-related immune impairment. To our best knowledge, we are the first to discover an age-dependent difference in gene expression of STING on a transcriptional level in human monocyte-derived macrophages possibly leading to a diminished interferon production.

Computational screening of phytocompounds from C. amboinicus identifies potential inhibitors of influenza A (H3N2) virus by targeting hemagglutinin

The H3N2 subtype of the influenza A virus continues to be a notable public health issue due to its association with seasonal epidemics and severe human morbidity. The constrained effectiveness of current antiviral medications, combined with the inevitable emergence of drug-resistant variants, mandates the exploration of innovative therapeutic approaches. This study focuses on the identification of phytocompounds from Coleus amboinicus with the potential to target hemagglutinin, viral protein involved in viral entry by binding to sialyl glycoconjugates receptors on the surface of host cells. Molecular docking studies were carried out to assess the efficacy of C. amboinicus phytocompounds with hemagglutinin receptor-binding site. The study revealed that among the 84 signature phytocompounds, isosalvianolic acid and salvianolic acid C showed the highest docking scores and favourable intermolecular interactions. Pharmacokinetic analysis and Pan-assay interference compounds (PAINS) filtering confirmed that isosalvianolic acid meets the criteria outlined in Lipinski's rule of five, exhibits favourable ADMET profiles and passes PAINS filters. Furthermore, the molecular dynamics simulations followed by radius of gyration (Rg), solvent accessible surface area (SASA), and MM-PBSA calculations for binding free energy, verified the stability of the docked complexes. Together, the study identifies isosalvianolic acid as a promising inhibitor of the H3N2 virus by binding to hemagglutinin, indicating its potential as a strategy for therapeutic intervention.

A Clinical and Economic Comparison of Cell-Based Versus Recombinant Influenza Vaccines in Adults 18-64 Years in the United States

BACKGROUND

This analysis compares the cost-effectiveness of a cell-based influenza vaccine to a recombinant influenza vaccine, and each to no vaccination. The analysis is based on United States (US) commercial and societal perspectives.

METHODS

A Susceptible-Exposed-Infectious-Recovered (SEIR) transmission model of the total US population followed with a cost-effectiveness model for 18-64-year-olds was used to estimate the clinical and economic impact of vaccination over one influenza season (2018-2019). Deterministic and probabilistic sensitivity analyses were conducted.

RESULTS

Both enhanced vaccines prevented a substantial number of influenza cases and influenza-related deaths compared to no vaccination. The cell-based vaccine was associated with higher quality-adjusted life years (QALYs) gained compared to the recombinant vaccine or no vaccination. The cell-based vaccine had a 36% lower vaccination cost, amounting to $2.8 billion in cost savings, compared to the recombinant vaccine. The incremental cost-effectiveness ratios (ICERs) for the cell-based vaccine, compared to the recombinant vaccine or no vaccination, were dominant from all payer perspectives, regardless of risk groups.

CONCLUSIONS

Overall, the cell-based vaccine was cost-saving compared to the recombinant vaccine for subjects aged 18-64 years in the US, achieving comparable health outcomes with a significant reduction in associated costs.

Contribution of immunoglobulin products in influencing seasonal influenza infection and severity in antibody immune deficiency patients receiving immunoglobulin replacement therapy

Seasonal and pandemic influenza infection present a potential threat to patients with antibody deficiency. The acceptance and effect of the current recommendation for annual vaccination against influenza for patients with antibody deficiency is not well investigated and due to antigenic drift or shift the protective capacity of regular IgG replacement therapy (IgRT) is considered low. This narrative review considers the effect of influenza vaccination in immunodeficient patients and discusses available information on the effect of immunoglobulin products on seasonal influenza infectivity and severity in antibody deficiency patients receiving IgRT. The humoral immune response to seasonal influenza vaccination is reduced in patients with antibody immune deficiency. However, there is no evidence that the proportion of patients with primary antibody deficiency who develop influenza illness, and the severity of such illness, is increased when compared with the general population. The IgRT that patients receive has been shown to contain neutralizing antibodies as a consequence of past flu infections against both the hemagglutinin and neuraminidase surface proteins and other viral internal proteins of different influenza A virus strains. Studies have demonstrated not only significant levels of specific but also cross-reactive antibodies against seasonal influenza virus strains. Thus, despite the yearly changes in influenza viral antigenicity that occur, IgRT could potentially contribute to the protection of patients against seasonal influenza. Currently, only limited clinical data are available confirming a preventative effect of IgRT with respect to seasonal influenza infection. In conclusion, there is some evidence that IgRT could contribute to protection against seasonal influenza in patients with antibody-related immunodeficiency. However, additional clinical data are needed to confirm the extent and relevance of this protection and identify the main responsible virus targets of that protection.

Seasonal Influenza Vaccine Literacy and Hesitancy of Elderly Czechs: An Analysis Using the 5C Model of Psychological Antecedents

Objectives

Seasonal influenza vaccination rates among the elderly in the Czech Republic are alarmingly low, making it one of the least vaccinated countries in Europe. This study explored the role of vaccine literacy and insurance coverage on vaccination status.

Methods

An analytical cross-sectional study was conducted in Summer 2023 using a self-administered questionnaire covering vaccine literacy (functional, interactive, and critical skills), negative perceptions towards influenza vaccination, and the 5C model (confidence, complacency, constraints, calculation, and collective responsibility). Individuals aged 55 and older were included in the study. Mediation analyses assessed the indirect effects of insurance coverage on vaccination status.

Results

Significant differences were noted in vaccination rates based on insurance coverage, chronic diseases, regular medication use, and previous COVID-19 and pneumococcal vaccinations. Vaccine literacy, especially interactive and critical skills, was higher among vaccinated individuals. Confidence and collective responsibility were significant promoters, while complacency and constraints were barriers to vaccination. Mediation analyses indicated that negative perceptions, confidence, and collective responsibility significantly mediated the relationship between insurance coverage and vaccination status.

Conclusion

Enhancing vaccine literacy and addressing psychological antecedents are crucial for improving influenza vaccination rates among the elderly. Policy measures should include improving vaccine literacy, building public confidence, and addressing negative perceptions.

Analyzing Changes in Attitudes and Behaviors towards Seasonal Influenza Vaccination in Spain's Adult Population over Three Seasons

Background/Objectives: The experience of the COVID-19 pandemic has turned the spotlight on the importance of public health measures and disease prevention. Despite this, the acceptance of influenza vaccination has remained low in most countries (and far from the 75% target set by the World Health Organization). The objective of this study has been to investigate how attitudes and behaviors regarding influenza vaccination in the Spanish adult population have changed over the last three years (from 2021 to 2024) in order to analyze trends in influenza vaccination. Methods: To this end, a cross-sectional study was conducted through 2206 telephone interviews, and the results were compared with those obtained in previous campaigns. Results: The findings indicate a significant decline in overall vaccination intent. Healthcare professionals remain the most influential factor in encouraging vaccination, yet there is a notable increase in the lack of vaccine recommendations, contributing to the decision not to vaccinate. This study also reveals low awareness of the influenza vaccine campaign, emphasizing the need for improved public health communication. Conclusions: To counteract these trends, this study recommends intensifying awareness campaigns, strengthening the role of healthcare providers in vaccine advocacy, and tailoring communication strategies. These efforts are crucial to enhancing vaccination coverage and protecting vulnerable populations against influenza.