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Background: To evaluate the influenza-like illness (ILI) and acute respiratory infection (ARI) case definitions in the diagnosis of COVID-19 and influenza in healthcare personnel (HCP)., Methods: We followed a cohort of 5752 HCP from November 2022 to May 2023. Symptomatic HCP were tested for SARS-CoV-2 and influenza by real-time PCR and/or rapid antigen detection test. ILI was defined as the sudden onset of ≥1 systemic symptom and ≥1 respiratory symptom. ARI was defined as the sudden onset of ≥1 respiratory symptom. Patients with respiratory symptoms were grouped either as ILI or as ARI based on the presence of fever, malaise, headache and/or myalgia., Results: Overall, 466 ILI cases and 383 ARI cases occurred. HCP with ILI had an adjusted odds ratio (aOR) of 22.05 [95% confidence interval (CI): 6.23-78.04] to be diagnosed with influenza. HCP with ARI had an aOR of 2.70 (95% CI: 1.88-3.88) to be diagnosed with COVID-19. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of ILI for influenza were 96.6%, 49.9%, 18.2%, and 99.2%, respectively. The sensitivity, specificity, PPV, and NPV of ARI for COVID-19 were 51.7%, 73.6%, 84.9%, and 34.8%, respectively. ILI and ARI had an overall correct classification rate of 89.6% and 74.1%, respectively., Conclusion: Our findings support the use of both ILI and ARI case definitions in the diagnosis of influenza and COVID-19 in HCP., Competing Interests: Declaration of competing interest Dr Maltezou received an honorarium from Novavax to participate in a symposium. The authors have no conflict of interest to declare., (Copyright © 2024 Australasian College for Infection Prevention and Control. Published by Elsevier B.V. All rights reserved.)

Objectives: To evaluate the efficacy and safety of ZX-7101A: an inhibitor of influenza viral cap-dependent endonuclease, in adults with uncomplicated influenza and explore treatment-emergent resistance., Methods: We conducted a randomized, double-blind, placebo-controlled, adaptive-design phase 2 and phase 3 studies (ZX-7101A-202) in adults with uncomplicated influenza. Eligible patients were randomized 1:1:1 to receive a single dose of 40 or 80 mg ZX-7101A or placebo, stratified by body weight and baseline composite symptom score. The primary efficacy endpoint was time to alleviation of influenza symptoms (TTAS) in intention-to-treat infected population., Results: The phase 2 trial suggested significantly shorter TTAS for ZX-7101A compared with placebo: the median TTAS of 40 or 80 mg ZX-7101A groups were 34.7 hours (95% CI, 22.8-43.4; p 0.005) and 45.8 hours (95% CI, 32.0-66.3; p 0.020), compared with 63.6 hours (95% CI, 43.9-93.4) in the placebo group. In the phase 3 trial, the TTAS of both ZX-7101A dose groups was significantly shortened relative to the that of placebo group: the median TTAS was shortened to 48.4 hours (95% CI, 40.5-55.6) for 40 mg group and 39.4 hours (95% CI, 35.8-49.3) for 80 mg group, compared with 62.9 hours (95% CI, 56.4-69.3) for placebo group (p 0.003 and p < 0.001, respectively). In the safety population, ZX-7101A treatment was associated with fewer adverse events, with 41.8% (100/239) in the 40 mg group, 44.2% (106/240) in the 80 mg group, and 53.8% (129/240) in the placebo group. The majority of adverse events were mild or moderate. Emergence of resistance to ZX-7101A through I38T amino acid substitution was detected in 5/278 (1.8%) patients., Discussion: ZX-7101A was an effective treatment for influenza with a single dose of either 40 mg or 80 mg, with more rapid alleviation of influenza symptoms vs. placebo. No safety concerns were identified with single dose treatment of ZX-7101A., (Copyright © 2024 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Highly pathogenic avian influenza (HPAI) clade 2.3.4.4b H5Nx viruses continue to cause episodic incursions and have been detected in more than 12 taxonomic orders encompassing more than 80 avian species, terrestrial and marine mammals, including lactating dairy cows. HPAI H5N1 spillover to dairy cattle creates a new interface for human exposure and raises food safety concerns. The presence of H5N1 genetic material in one out of five retail pasteurized milk samples in the USA has prompted the evaluation of the pasteurization processes for the inactivation of influenza viruses. Our study examined whether pasteurization could effectively inactivate HPAI H5N1 spiked into raw whole milk. First, we heated 1 mL of non-homogenized cow milk samples to attain an internal temperature of 63°C or 72°C and spiked with 6.3 log 10 EID 50 of clade 2.3.4.4b H5N1 virus. Complete inactivation was achieved after incubation of the H5N1 spiked raw milk at 63°C for 30 min. In addition, viral inactivation was observed in seven of eight experimental replicates when treated at 72°C for 15s. In one of the replicates, a 4.44 log 10 virus reduction was achieved, which is about 1 log higher than the average viral quantities detected in bulk milk in affected areas. Therefore, we conclude that pasteurization of milk is an effective strategy for mitigation of the risk of human exposure to milk contaminated with H5N1 virus., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Crown Copyright © 2024. Published by Elsevier Ltd. All rights reserved.)

Objectives: Avian influenza (AI) H5N6 has replaced H5N1 as the predominant strain, and the increasing number of cases and complex recombination patterns pose significant threats to human health., Methods: The data were collected on human cases of AI H5N6 from the National Surveillance of Notifiable Infectious Disease Programme in Guangxi and used MEGA software to conduct phylogenetic analysis with published reference strains obtained from the GISAID database., Results: Between January 1 and December 31, 2021, 11 cases of human AI H5N6 infection were reported in Guangxi. All HA genes belonged to clade 2.3.4.4, with only one virus belonging to 2.3.4.4h and the remaining viruses falling into 2.3.4.4b. Phylogenetic analysis of the genes was conducted, and some substitutions were detected in the HA gene, M1 protein, and NS1 protein. A close relationship between Guangxi viruses and AI viruses of poultry origin has been observed., Conclusion: Given the contamination of live poultry markets and backyard poultry, AI H5N6 variants and genotypes will continuously emerge; therefore, enhancing surveillance is crucial for pandemic preparedness., Competing Interests: Declarations of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The emergence of new influenza virus strains presents a continuous challenge for global public health. mRNA technology offers a promising platform for rapidly developing therapeutics, particularly monoclonal antibodies, that can protect against viral infections. In this study, we engineered mRNA constructs encoding two types of antibodies: secreted antibodies specific to the hemagglutinin of the influenza A virus, based on previously characterized Fi6 antibodies, and intracellular Fab fragments targeting the nucleoprotein of the influenza B virus, derived from the 2/3 antibodies. The administration of mRNA constructs in vitro resulted in the successful synthesis of functional antibodies, which exhibited antiviral activity against influenza viruses. This study confirms the feasibility of using mRNA technology to develop therapeutic antibodies against influenza virus infections. The findings pave the way for future clinical applications of mRNA-based therapeutics, enhancing preparedness for emerging viral threats., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Drug resistance is an important factor in the fight against influenza A virus (IAV). Natural products offer a rich source of lead compounds for the discovery of novel antiviral drugs. In a previous study, we isolated the sorbicillinoid polyketide HSL-2 from the mycelium of fungus Trichoderma sp. T-4-1. Here, we show that this compound exerts strong antiviral activity against a panel of IAVs., Methods: The immunofluorescence and qRT-PCR assays were used to detect the inhibitory effect of HSL-2 toward the replication of influenza virus and IAV-induced expression of the pro-inflammatory cytokines such as TNF-α, IL-6, and IL-1β., Results: The results indicated that HSL-2 inhibited influenza virus replication, and it significantly inhibited IAV-induced overexpression of the pro-inflammatory cytokines TNF-α, IL-6, and IL-1β through modulating the PPAR-γ/NF-κB pathway. Notably, this effect was decreased when cells were transfected with PPAR-γ siRNA or treated with the PPAR-γ inhibitor T0070907. In addition, HSL-2 was able to attenuate lung inflammatory responses and to improve lung lesions in a mouse model of IAV infection., Conclusions: In this paper, we identified a microbial secondary metabolite, HSL-2, with anti-influenza virus activity. This report is the first to describe the antiviral activity and mechanism of action of HSL-2, and it provides a new strategy for the development of novel anti-influenza virus drugs from natural sources., (Copyright © 2024 Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Infection Prevention and Control. Published by Elsevier Ltd. All rights reserved.)

We report the development of an amplification-free nucleic acid assay using lateral flow test strips. M13mp18 nanoscaffold signal amplification permitted the visual detection of H1N1 RNA in 20 min. M13mp18 nanoscaffold supported a set of backbone, variable, detection, and modified oligonucleotides. A bridging-type FAM probe/H1N1 RNA/M13mp18 was used in the lateral flow test strip format. The bridging-type complexes were captured on the test zone. The lower limit of detection of specific H1N1 RNA was 1 pM. The method directly detected H1N1 RNA without amplification, eliminating the risk of amplicon contamination and lessening the chance of false positives. This biosensor has potential value for field testing in resource-limited settings and monitoring viral loads in recovering patients. The amplification-free lateral flow detection of RNA provides an alternative between amplification-based RNA assays and protein antigen assays for facilitating the rapid identification of H1N1 virus during point-of-care testing., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The quasispecies of the influenza virus poses a significant challenge for developing effective therapies. Current antiviral drugs such as oseltamivir, zanamivir, peramivir and baloxavir marboxil along with seasonal vaccines have limitations due to viral variability caused by antigenic drift and shift as well as the development of drug resistance. Therefore, there is a clear need for novel antiviral agents targeting alternative mechanisms, either independently or in combination with existing modalities, to reduce the impact of influenza virus-related infections. The influenza nucleoprotein (NP) is a key component of the viral ribonucleoprotein complex. The multifaceted nature of the NP makes it an attractive target for antiviral intervention. Recent reports have identified inhibitors that specifically target this protein. Recognizing the importance of developing influenza treatments for potential pandemics, this review explores the structural and functional aspects of NP and highlights its potential as an emerging target for anti-influenza drugs. We discuss various strategies for targeting NP, including RNA binding, oligomerization, and nuclear export, and also consider the potential of NP-based vaccines. Overall, this review provides insights into recent developments and future perspectives on targeting influenza NP for antiviral therapies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

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., Competing Interests: Declaration of Competing Interest There is no conflict of interest between the author and any coauthor of this article., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Influenza A viruses (IAVs) and endemic coronaviruses (eCoVs) are common etiologic agents for seasonal respiratory infections. The human H1N1 of IAV and coronavirus OC43 (HCoV-OC43) can result in hospitalization, acute respiratory distress syndrome (ARDS), and even death, particularly in immunocompromised individuals. They infect the epithelium of the respiratory tract by interacting with host cell sialic acid (Sia)- linked receptors whose synthesis is catalyzed by sialyltransferases (STs). Viral coinfection is challenging to treat because of the need to target specific components of two or more distinct pathogens. Emerging drug and vaccine resistance due to the high mutation rate of viral genomes further complicates the treatment and prevention of viral infection. Sialylation mediated by STs may be a potential drug target for treating viral diseases. ST is an attractive target because it could be effective before identifying the pathogen that has occurred, providing a novel direction for overcoming drug resistance and achieving a broad-spectrum antiviral effect. We developed an H1N1 and OC43 mono or coinfection model using 14 days post-plating (14 PP) human primary small airway epithelial cells (HSAEC) grown on transwell inserts at an air-fluid interface (ALI), mimicking in vivo cellular dynamics. Using this model, we have observed that mono or coinfection with OC43 and H1N1 results in increased sialic acid levels and synergistic viral infection. We showed for the first time that H1N1 and OC43 mono- and coinfection in HSAEC caused increased expression and activity of STs, which can be blocked by pan-STs inhibitor (3Fax-Peracetyl Neu5Ac) with no host cell toxicity., Competing Interests: Declaration of competing interest The author is an Editorial Board Member/Editor-in-Chief/Associate Editor/Guest Editor for Antiviral Research and was not involved in the editorial review or the decision to publish this article. The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: We do not have any commercial associations that might pose a conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: We examined the added value of serologic testing for estimating influenza virus infection incidence based on illness surveillance with molecular testing versus periodic serologic testing., Methods: Pregnant persons unvaccinated against influenza at <28 weeks gestation were enrolled before the 2017 and 2018 influenza seasons in Peru and Thailand. Blood specimens were collected at enrollment and ≤14 days postpartum for testing by hemagglutination inhibition assay for antibodies against influenza reference viruses. Seroconversion was defined as a ≥4-fold rise in antibody titers from enrollment to postpartum with the second specimen's titer of ≥40. Throughout pregnancy, participants responded to twice weekly surveillance contacts asking about influenza vaccination and influenza-like symptoms (ILS). A mid-turbinate swab was collected with each ILS episode for influenza real-time reverse transcription polymerase chain reaction (rRT-PCR)., Results: Of 1,466 participants without evidence of influenza vaccination during pregnancy, 296 (20.2%) had evidence of influenza virus infections. Fifteen (5.1%) were detected by rRT-PCR only, 250 (84.4%) by serologic testing only, and 31 (10.5%) by both methods., Conclusions: Influenza virus infections during pregnancy occurred in 20% of cohort participants; >80% were not detected by a broad illness case definition coupled with rRT-PCR., Competing Interests: Declarations of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Viral coinfections are responsible for a significant portion of cases of patients hospitalized with influenza-like illness. As our awareness of viral coinfections has increased, researchers have started to experimentally examine some of the virus-virus interactions underlying these infections. One mechanism of interaction between viruses is through the innate immune response. This seems to occur primarily through the interferon response, which generates an antiviral state in nearby uninfected cells, a phenomenon know as the bystander effect. Here, we develop a mathematical model of two viruses interacting through the bystander effect. We find that when the rate of removal of cells to the protected state is high, growth of the first virus is suppressed, while the second virus enjoys sole access to the protected cells, enhancing its growth. Conversely, growth of the second virus can be fully suppressed if its ability to infect the protected cells is limited., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the seasonal influenza virus are spreading among humans concurrently, especially with the ongoing replacement of mutant strains. It is challenging to differentiate between symptoms for therapy due to the comparable symptoms following infection with the SARS-CoV-2 variants and influenza viruses. Meanwhile, in order to achieve rapid point-of-care testing (POCT) to manage the spread of the disease, we developed a dual lateral flow strip based on colloidal gold-labeled monoclonal antibodies that can perform differential detection of SARS-CoV-2 variants and influenza A viruses (IAV) in this study. High-affinity monoclonal antibodies (mAbs) targeting SARS-CoV-2 and IAV were prepared to capture antigens and labeled with colloidal gold nanoparticles (AuNPs). Based on high-affinity mAbs, two targets were immobilized on one nitrocellulose (NC) membrane to establish the lateral flow strip (LFS) for differential diagnosis of SARS-CoV-2 and IAV. With no reactivity to other viruses, this LFS is extremely specific and can only identify SARS-CoV-2 and IAV. The LFS showed a limit of detection (LOD) of 4.88 ng/mL for the Omicron BA.2 RBD protein and 2.44 ng/mL for the nucleoprotein (NP) protein of H1N1. When analyzing 16 SARS-CoV-2 positive clinical samples, eight IAV positive clinical samples, and six negative samples that had already been pre-confirmed by commercial kits, its clinical application is effectively and accurately proven. These results demonstrated that the LFS integrated with AuNPs has great potential to facilitate quick, easy, and reliable POCT diagnosis for promoting the control of infectious diseases., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The similar transmission patterns and early symptoms of respiratory viral infections, particularly severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza (H1N1), and respiratory syncytial virus (RSV), pose substantial challenges in the diagnosis, therapeutic management, and handling of these infectious diseases. Multiplexed point-of-care testing for detection is urgently needed for prompt and efficient disease management. Here, we introduce an electrochemical paper-based analytical device (ePAD) platform for multiplexed and label-free detection of SARS-CoV-2, H1N1, and RSV infection using immobilized pyrrolidinyl peptide nucleic acid probes. Hybridization between the probes and viral nucleic acid targets causes changes in the electrochemical response. The resulting sensor offers high sensitivity and low detection limits of 0.12, 0.35, and 0.36 pM for SARS-CoV-2 (N gene), H1N1, and RSV, respectively, without showing any cross-reactivities. The amplification-free detection of extracted RNA from 42 nasopharyngeal swab samples was successfully demonstrated and validated against reverse-transcription polymerase chain reaction (range of cycle threshold values: 17.43-25.89). The proposed platform showed excellent clinical sensitivity (100 %) and specificity (≥97 %) to achieve excellent agreement (κ ≥ 0.914) with the standard assay, thereby demonstrating its applicability for the screening and diagnosis of these respiratory diseases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Introduction: While respiratory syncytial virus (RSV) is one of the most common pathogens in adults admitted to the ICU due to respiratory diseases, no reports regarding the occurrence rate of RSV infections in adults in Japan during the COVID-19 pandemic exist., Patients and Methods: We conducted this retrospective study to examine the exact occurrence rate of RSV infections in adults. We reviewed all patients (≥18 years) with any respiratory symptoms who received quantitative polymerase chain reaction (PCR) using nasopharyngeal samples for respiratory viruses by GeneLEAD at the Aichi Medical University Hospital between November 2022 and November 2023., Results: A total of 541 adult patients who underwent PCR test were enrolled in this study. RSV was identified in 18 cases (3.3 %); 8 (1.5 %) upper and 10 (1.8 %) lower respiratory tract infections. Influenza A and SARS-CoV-2 were found in 10 (1.8 %) and 61 (11.3 %), respectively. Patients with RSV infections and COVID-19 had more comorbidities than those with Influenza virus infections. As for RSV-associated with lower respiratory tract infection cases, 10 developed acute respiratory failure, resulting in 1 fatal case due to pneumonia and 1 died of septic shock due to ileus. The 30-, 90-day mortality rates were 1 (6 %) and 2 (11 %) respectively., Conclusion: About 3 % of adults had RSV infections during the COVID-19 pandemic. The outcomes of RSV infections in adults were similar to those by COVID-19. Those with comorbidities should have a preventive method against RSV infections, the same as for COVID-19., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2024 Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Infection Prevention and Control. Published by Elsevier Ltd. All rights reserved.)

Avian influenza viruses crossing the host barrier to infect humans have caused great panic in human society and seriously threatened public health. Herein, we revealed that knockdown of SRSF7 significantly down-regulated influenza virus titers and viral protein expression. We further observed for the first time that human SRSF7, but not avian SRSF7, significantly inhibited polymerase activity (PB2 627 E). Molecular mapping demonstrated that amino acids 206 to 228 of human SRSF7 play a decisive role in regulating the polymerase activity, which contains the amino acid motif absent in avian SRSF7. Importantly, our results illustrated that the PB2 627 K-encoding influenza virus induces SRSF7 protein degradation more strongly via the lysosome pathway and not via the proteasome pathway. Functional enrichment analysis of SRSF7-related KEGG pathways indicated that SRSF7 is closely related to cell growth and death. Lastly, our results showed that knocking down SRSF7 interferes with normal polymerase activity. Taken together, our results advance our understanding of interspecies transmission and our findings point out new targets for the development of drugs preventing or treating influenza virus infection., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 The Author(s). Published by Elsevier Masson SAS.. All rights reserved.)

Seasonal influenza is an annually severe crisis for global public health, and an ideal influenza vaccine is expected to provide broad protection against constantly drifted strains. Compared to highly flexible hemagglutinin (HA), increasing data have demonstrated that neuraminidase (NA) might be a potential target against influenza variants. In the present study, a series of genetic algorithm-based mosaic NA were designed, and then cloned into recombinant DNA and replication-defective Vesicular Stomatitis Virus (VSV) vector as a novel influenza vaccine candidate. Our Results showed that DNA prime/VSV boost strategy elicited a robust NA-specific Th1-dominated immune response, but the traditional inactivated influenza vaccine elicited a Th2-dominated immune response. More importantly, the superior NA-specific immunity induced by our strategy could confer both a full protection against lethal homologous influenza challenge and a partial protection against heterologous influenza infection. These findings will provide insights on designing NA-based universal vaccine strategy against influenza variants., Competing Interests: Declaration of competing interest J.G. is employed by Shenzhen Kangtai Biological Products Co., Ltd. Other authors declare that the there are no conflicts of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Multiplex detection can enhance diagnostic precision and improve diagnostic efficiency, providing important assistance for epidemiological investigation and epidemic prevention. There is a great need for multi-detection sensing platforms to accurately diagnose diseases. Herein, we reported a μPAD-based chemiluminescence (CL) assay for ultrasensitive multiplex detection of AIV biomarkers, based on three DNAzyme/Lum/PEI/CaCO 3 . Three time-resolved CL signals were sequentially generated with detection limits of 0.32, 0.34, and 0.29 pM for H1N1, H7N9, and H5N1, respectively, and with excellent selectivity against interfering DNA. The recovery test in human serum displayed satisfactory analysis capabilities for complex biological samples. The μPAD-based CL assay achieved multiplex detection within 70 s, with a high time resolution of 20 s. The proposed strategy has the advantages of low cost, high sensitivity, good selectivity, and wide time resolution, the μPAD-based CL assay has shown great potential in the early and accurate diagnosis of diseases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

In search of novel therapeutic options to treat influenza virus (IV) infections, we previously identified a series of inhibitors that act by disrupting the interactions between the PA and PB1 subunits of the viral RNA polymerase. These compounds showed broad-spectrum antiviral activity against human influenza A and B viruses and a high barrier to the induction of drug resistance in vitro. In this short communication, we investigated the effects of combinations of the PA-PB1 interaction inhibitor 54 with oseltamivir carboxylate (OSC), zanamivir (ZA), favipiravir (FPV), and baloxavir marboxil (BXM) on the inhibition of influenza A and B virus replication in vitro. We observed a synergistic effect of the 54/OSC and 54/ZA combinations and an antagonistic effect when 54 was combined with either FPV or BXM. Moreover, we demonstrated the efficacy of 54 against highly pathogenic avian influenza viruses (HPAIVs) both in cell culture and in the embryonated chicken eggs model. Finally, we observed that 54 enhances OSC protective effect against HPAIV replication in the embryonated eggs model. Our findings represent an advance in the development of alternative therapeutic strategies against both human and avian IV infections., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Baloxavir marboxil (baloxavir), approved as an anti-influenza drug in Japan in March 2018, can induce reduced therapeutic effectiveness due to PA protein substitutions. We assessed PA substitutions in clinical samples from influenza-infected children and adults pre- and post-baloxavir treatment, examining their impact on fever and symptom duration. During the 2022-2023 influenza season, the predominant circulating influenza subtype detected by cycling-probe RT-PCR was A(H3N2) (n = 234), with a minor circulation of A(H1N1)pdm09 (n = 10). Of the 234 influenza A(H3N2) viruses collected prior to baloxavir treatment, 2 (0.8%) viruses carry PA/I38T substitution. One virus was collected from a toddler and one from an adult, indicating the presence of viruses with reduced susceptibility to baloxavir, without prior exposure to the drug. Of the 54 paired influenza A(H3N2) viruses collected following baloxavir treatment, 8 (14.8%) viruses carried E23 K/G, or I38 M/T substitutions in PA. Variant calling through next-generation sequencing (NGS) showed varying proportions (6-100 %), a polymorphism and a mixture of PA/E23 K/G, and I38 M/T substitutions in the clinical samples. These eight viruses were obtained from children aged 7-14 years, with a median fever duration of 16.7 h and a median symptom duration of 93.7 h, which were similar to those of the wild type. However, the delayed viral clearance associated with the emergence of PA substitutions was observed. No substitutions conferring resistance to neuraminidase inhibitors were detected in 37 paired samples collected before and following oseltamivir treatment. These findings underscore the need for ongoing antiviral surveillance, informing public health strategies and clinical antiviral recommendations for seasonal influenza., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

In Japan, influenza activity was low throughout the COVID-19 pandemic until the 2022-23 season, when the first influenza outbreak occurred since the 2020-21 season. In our influenza surveillance during the COVID-19 pandemic, co-infection with SARS-CoV-2 and influenza virus had not been detected; however, in January 2024, we identified three pediatric outpatients co-infected with these viruses: one with SARS-CoV-2 Omicron EG.5 sublineage HK.3 and influenza A(H3N2) and two with SARS-CoV-2 Omicron BA.2.86 sublineage JN.1.5 and influenza A(H1N1)pdm09. We evaluated the susceptibility of SARS-CoV-2 against RNA-dependent RNA polymerase inhibitors (remdesivir and molnupiravir) and 3C-like protease inhibitors (nirmatrelvir and ensitrelvir), and that of influenza viruses against neuraminidase inhibitors (oseltamivir, peramivir, zanamivir, and laninamivir) and the cap-dependent endonuclease inhibitor baloxavir. All viruses tested were susceptible to these antiviral drugs and did not possess amino acid substitutions associated with reduced antiviral susceptibility. The patients were treated with anti-influenza drugs and did not develop severe symptoms despite the co-infection. Since SARS-CoV-2 and influenza viruses continue to evolve, continuous monitoring of their circulation remains essential to assess public health measures and support clinical management., Competing Interests: Declarations of competing interest Yoshihiro Kawaoka has received collaborative research funds from FUJIFILM Toyama Chemical Co. LTD, Shionogi & Co. LTD, and Daiichi Sankyo Pharmaceutical and is a founder of FluGen. Other authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Baloxavir acid (BXA) is a pan-influenza antiviral that targets the cap-dependent endonuclease of the polymerase acidic (PA) protein required for viral mRNA synthesis. To gain a comprehensive understanding on the molecular changes associated with reduced susceptibility to BXA and their fitness profile, we performed a deep mutational scanning at the PA endonuclease domain of an A (H1N1)pdm09 virus. The recombinant virus libraries were serially passaged in vitro under increasing concentrations of BXA followed by next-generation sequencing to monitor PA amino acid substitutions with increased detection frequencies. Enriched PA amino acid changes were each introduced into a recombinant A (H1N1)pdm09 virus to validate their effect on BXA susceptibility and viral replication fitness in vitro. The I38 T/M substitutions known to confer reduced susceptibility to BXA were invariably detected from recombinant virus libraries within 5 serial passages. In addition, we identified a novel L106R substitution that emerged in the third passage and conferred greater than 10-fold reduced susceptibility to BXA. PA-L106 is highly conserved among seasonal influenza A and B viruses. Compared to the wild-type virus, the L106R substitution resulted in reduced polymerase activity and a minor reduction of the peak viral load, suggesting the amino acid change may result in moderate fitness loss. Our results support the use of deep mutational scanning as a practical tool to elucidate genotype-phenotype relationships, including mapping amino acid substitutions with reduced susceptibility to antivirals., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Objectives: This study sought to detect and characterize influenza A (IAV) and influenza D (IDV) viruses circulating among commercial birds and shop owners in Pakistan's live bird markets., Methods: Oropharyngeal swabs (n = 600; n = 300 pools) collected from poultry and nasopharyngeal swabs (n = 240) collected from poultry workers were studied for molecular evidence of IAV and IDV using real-time and conventional real-time reverse transcription polymerase chain reaction protocols., Results: Nineteen (6.3%) poultry pools were positive for IAV and 73.9% of these were positive for H9N2 subtypes. Two (0.83%) poultry workers had evidence of IAV, and both were also H9N2 subtypes. The poultry and human IAV-positive specimens all clustered phylogenetically by Sanger and next-generation sequencing with previously detected H9N2 poultry isolates. No field specimens were positive for IDV., Conclusion: H9N2 IAV is likely enzootic in Punjab Province Pakistan's live bird markets and may be colonizing the noses of workers and market visitors. Regular monitoring for avian influenza-associated human illness in Punjab seems to be a needed public measure., Competing Interests: Declarations of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Influenza infection is highly contagious respiratory illness triggered by the influenza virus, bearing substantial implications for global health. Influenza B viruses, specifically the Victoria and Yamagata lineages, have contributed to the disease burden, and the mismatch between circulating strains and vaccine strains has led to increased mortality and economic costs. Understanding the global epidemiology, seasonal variations, and genetic characteristics of influenza B is crucial for effective prevention and control strategies., Methods: The study investigated influenza B viruses in Shiraz, Iran during the Oct 2017 to Jan 2018. Throat swabs were collected from 235 individuals under 15 with influenza-like symptoms including fever and cough. Samples were stored at -80°C and transported to the lab for further analysis. Viral RNA was extracted and analyzed using Real-time PCR. The hemagglutinin (HA) gene of positive samples was sequenced, and phylogenetic trees were constructed. Amino acids indicative of adaptive mutations were identified using global sequence data., Results: 23 of 235 samples (9.7 %) were positive for influenza B virus. The most common clinical manifestations were rhinorrhea and myalgia, with 20 individuals (87 % of the 23 infected people) each showing these symptoms. The phylogenetic analysis of the HA gene showed that the Victoria isolates were close to the B/Brisbane/60/2008 strain (12.5 % of the positive samples) and belonged to clade-1A, while the Yamagata isolates were close to the B/Phuket/3037/2013 strain (87.5 % of the positive samples) and belonged to clade-3., Conclusion: The study highlights the need for importance vaccine coverage in the Shiraz region to address limited genetic diversity and strain mismatch. Continuous surveillance of mutations in the HA gene resulting in amino acid substitutions and their impact on vaccine efficacy is crucial. This study showed that the circulation of influenza B in Shiraz matched with the recommended Yamagata vaccine strain. These findings contribute to the understanding of influenza B dynamics and emphasize the importance of region-specific prevention and control strategies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Influenza A virus (IAV) continuously poses a considerable threat to global health through seasonal epidemics and recurring pandemics. IAV RNA-dependent RNA polymerases (FluPol) mediate the transcription of RNA and replication of the viral genome. Searching for targets that inhibit viral polymerase activity helps us develop better antiviral drugs. Here, we identified heterogeneous nuclear ribonucleoprotein A/B (hnRNPAB) as an anti-influenza host factor. hnRNPAB interacts with NP of IAV to inhibit the interaction between PB1 and NP, which is dependent on the 5-amino-acid peptide of the hnRNPAB C-terminal domain (aa 318-322). We further found that the 5-amino-acid peptide blocks the interaction between PB1 and NP to destroy the FluPol activity. In vivo studies demonstrate that hnRNPAB-deficient mice display higher viral burdens, enhanced cytokine production, and increased mortality after influenza infection. These data demonstrate that hnRNPAB perturbs FluPol complex conformation to inhibit IAV infection, providing insights into anti-influenza defense mechanisms., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

We compared the duration of fever in children infected with A(H1N1)pdm09, A(H3N2), or influenza B viruses following treatment with baloxavir marboxil (baloxavir) or neuraminidase inhibitors (NAIs) (oseltamivir, zanamivir, or laninamivir). This observational study was conducted at 10 outpatient clinics across 9 prefectures in Japan during the 2012-2013 and 2019-2020 influenza seasons. Patients with influenza rapid antigen test positive were treated with one of four anti-influenza drugs. The type/subtype of influenza viruses were identified from MDCK or MDCK SIAT1 cell-grown samples using two-step real-time PCR. Daily self-reported body temperature after treatment were used to evaluate the duration of fever by treatment group and various underlying factors. Among 1742 patients <19 years old analyzed, 452 (26.0%) were A(H1N1)pdm09, 827 (48.0%) A(H3N2), and 463 (26.0%) influenza B virus infections. Among fours treatment groups, baloxavir showed a shorter median duration of fever compared to oseltamivir in univariate analysis for A(H1N1)pdm09 virus infections (baloxavir, 22.0 h versus oseltamivir, 26.7 h, P < 0.05; laninamivir, 25.5 h, and zanamivir, 25.0 h). However, this difference was not significant in multivariable analyses. For A(H3N2) virus infections, there were no statistically significant differences observed (20.3, 21.0, 22.0, and 19.0 h) uni- and multivariable analyses. For influenza B, baloxavir shortened the fever duration by approximately 15 h than NAIs (20.3, 35.0, 34.3, and 34.1 h), as supported by uni- and multivariable analyses. Baloxavir seems to have comparable clinical effectiveness with NAIs on influenza A but can be more effective for treating pediatric influenza B virus infections than NAIs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Human interferon α2 (IFNα2) is a cytokine with broad-spectrum antiviral activity, and its engineered forms are widely used to treat viral infections. However, IFNα2 may trigger proinflammatory responses and underlying side effects during treatment. Trefoil factor 2 (TFF2) is a secreted protein with anti-inflammatory properties. Here, we explored whether coupling IFNα2 to TFF2 in a two-in-one fusion form could combine the beneficial effects of both molecules on viral infections toward a more desirable treatment outcome. We engineered two forms of human IFNα2 and TFF2 fusion proteins, IFNα2-TFF2-Fc (ITF) and TFF2-IFNα2-Fc (TIF), and examined their properties in vitro in comparison to IFNα2 and TFF2 alone. RNA-Seq was further used to explore such comparison on dynamic gene regulation at transriptomic level. These in vitro assessments collectively indicated that TIF largely retained the antiviral activity of IFNα2 while being a weaker inflammation inducer, consistent with the presence of TFF2 activity. We further demonstrated the superiority of TIF over IFNα2 or TFF2 alone in treating influenza infection using a mouse infection model. Together, our study provided evidence supporting that, by possessing antiviral activity conferred by IFNα2 with complementation from TFF2 in suppressing the inflammatory side effects, the fusion proteins, particularly TIF, represent more effective agents against influenza and other respiratory viral infections than IFNα2 or TFF2 alone. It implies that merging two molecules with complementary functions holds potential for developing novel therapeutics against viral infections., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The most widely used class of antivirals available for Influenza treatment are the neuraminidase inhibitors (NAI) Oseltamivir and Zanamivir. However, amino acid (AA) substitutions in the neuraminidase may cause reduced inhibition or high antiviral resistance. In Mexico, the current state of knowledge about NAI susceptibility is scarce, in this study we report the results of 14 years of Influenza surveillance by phenotypic and genotypic methods. A total of 255 isolates were assessed with the NAI assay, including Influenza A(H1N1)pdm09, A(H3N2) and Influenza B (IBV). Furthermore, 827 sequences contained in the GISAID platform were analyzed in search of relevant mutations.Overall, five isolates showed highly reduced inhibition or reduced inhibition to Oseltamivir, and two showed reduced inhibition to Zanamivir in the NAI assays. Additionally, five A(H1N1)pdm09 sequences from the GISAID possessed AA substitutions associated to reduced inhibition to Oseltamivir and none to Zanamivir. Oseltamivir resistant A(H1N1)pdm09 harbored the H275Y mutation. No genetic mutations were identified in Influenza A(H3N2) and IBV. Overall, these results show that in Mexico the rate of NAI resistance is low (0.6%), but it is essential to continue the Influenza surveillance in order to understand the drug susceptibility of circulating strains., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

The high disease burden of influenza virus poses a significant threat to human health. Optimized diagnostic technologies that combine speed, sensitivity, and specificity with minimal equipment requirements are urgently needed to detect the many circulating species, subtypes, and variants of influenza at the point of need. Here, we introduce such a method using Streamlined Highlighting of Infections to Navigate Epidemics (SHINE), a clustered regularly interspaced short palindromic repeats (CRISPR)-based RNA detection platform. Four SHINE assays were designed and validated for the detection and differentiation of clinically relevant influenza species (A and B) and subtypes (H1N1 and H3N2). When tested on clinical samples, these optimized assays achieved 100% concordance with quantitative RT-PCR. Duplex Cas12a/Cas13a SHINE assays were also developed to detect two targets simultaneously. This study demonstrates the utility of this duplex assay in discriminating two alleles of an oseltamivir resistance (H275Y) mutation as well as in simultaneously detecting influenza A and human RNAse P in patient samples. These assays have the potential to expand influenza detection outside of clinical laboratories for enhanced influenza diagnosis and surveillance., Competing Interests: Disclosure Statement J.A.-S., P.C.S., and C.M. are inventors on a pending patent application held by the Broad Institute (international patent application number PCT/US2021/049145), which covers the SHINE technology. P.C.S. is a cofounder of, shareholder in, and consultant to Sherlock Biosciences, Inc., and Delve Bio, as well as a board member of and shareholder in Danaher Corp. C.M. is a cofounder of Carver Biosciences, a startup company developing Cas13-based antivirals, and holds equity in Carver Biosciences., (Copyright © 2024 Association for Molecular Pathology and American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Objectives: The COVID-19 pandemic significantly changed respiratory viruses' epidemiology due to non-pharmaceutical interventions and possible viral interactions. This study investigates whether the circulation patterns of respiratory viruses have returned to pre-pandemic norms by comparing their peak timing and duration during the first three SARS-CoV-2 seasons to pre-pandemic times., Methods: Global Influenza Surveillance and Response System data from 194 countries (2014-2023) was analyzed for epidemic peak timing and duration, focusing on pre-pandemic and pandemic periods across both hemispheres and the intertropical belt. The analysis was restricted to countries meeting specific data thresholds to ensure robustness., Results: In 2022/2023, the northern hemisphere experienced earlier influenza and respiratory syncytial virus (RSV) peaks by 1.9 months (P <0.001). The duration of influenza epidemics increased by 2.2 weeks (P <0.001), with RSV showing a similar trend. The southern hemisphere's influenza peak shift was not significant (P = 0.437). Intertropical regions presented no substantial change in peak timing but experienced a significant reduction in the duration for human metapneumovirus and adenovirus (7.2 and 6.5 weeks shorter, respectively, P <0.001)., Conclusions: The pandemic altered the typical patterns of influenza and RSV, with earlier peaks in 2022 in temperate areas. These findings highlight the importance of robust surveillance data to inform public health strategies on evolving viral dynamics in the years to come., Competing Interests: Declaration of Competing Interest MH and ImG are employees of CSL Seqirus and may hold shares. JP declares that Nivel has received research grants which concern the epidemiology of influenza and vaccination against influenza from WHO, Sanofi, and the Foundation for Influenza Epidemiology. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Influenza A virus (IAV) infections pose a global health challenge that necessitates a comprehensive understanding of the host immune response to devise effective therapeutic interventions. As monocytes and macrophages play crucial roles in host defence, inflammation, and repair, this review explores the intricate journey of these cells during and after IAV infection. First, we highlight the dynamics and functions of lung-resident macrophage populations post-IAV. Second, we review the current knowledge of recruited monocytes and monocyte-derived cells, emphasising their roles in viral clearance, inflammation, immunomodulation, and tissue repair. Third, we shed light on the consequences of IAV-induced macrophage alterations on long-term lung immunity. We conclude by underscoring current knowledge gaps and exciting prospects for future research in unravelling the complexities of macrophage responses to respiratory viral infections., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Objectives: The aim of this study was to analyze the viral load (VL) using cycle threshold (Ct) in patients infected with influenza A (H3N2)., Methods: This prospective study was conducted during the 2022-2023 influenza season in sentinel, non-sentinel, and hospitalized patients of Castilla y León (Spain). Respiratory samples were obtained from nasopharyngeal swabs and analyzed by quantitative reverse transcription-polymerase chain reaction specific for influenza A (H3N2) to obtain the Ct value., Results: A total of 1047 individuals were enrolled (174 [16.6%] sentinel, 200 [19.1%] non-sentinel, 673 [64.3%] hospitalized). The mean Ct value was lower in infants, young children, and in the elderly, with a sharp increase in the last from 65 years until 90 years. In addition, the lower Ct values were observed in non-sentinel patients and then in hospitalized patients, probably because non-sentinel are outpatients in the acute phase of the influenza infection., Conclusions: A higher VL (lower Ct value) is related to the extreme ages of life: children and the elderly. Furthermore, a higher VL is related with the care setting, being probably higher in outpatients because they are in the acute phase of the disease and slightly lower in hospitalized patients because they are attended during the post-acute phase., Competing Interests: Declarations of competing interest The authors have no competing interests to declare., (Copyright © 2024. Published by Elsevier Ltd.)

Background: The prevalence of different types/subtypes varies across seasons and countries for seasonal influenza viruses, indicating underlying interactions between types/subtypes. The global interaction patterns and determinants for seasonal influenza types/subtypes need to be explored., Methods: Influenza epidemiological surveillance data, as well as multidimensional data that include population-related, environment-related, and virus-related factors from 55 countries worldwide were used to explore type/subtype interactions based on Spearman correlation coefficient. The machine learning method Extreme Gradient Boosting (XGBoost) and interpretable framework SHapley Additive exPlanation (SHAP) were utilized to quantify contributing factors and their effects on interactions among influenza types/subtypes. Additionally, causal relationships between types/subtypes were also explored based on Convergent Cross-mapping (CCM)., Results: A consistent globally negative correlation exists between influenza A/H3N2 and A/H1N1. Meanwhile, interactions between influenza A (A/H3N2, A/H1N1) and B show significant differences across countries, primarily influenced by population-related factors. Influenza A has a stronger driving force than influenza B, and A/H3N2 has a stronger driving force than A/H1N1., Conclusion: The research elucidated the globally complex and heterogeneous interaction patterns among influenza type/subtypes, identifying key factors shaping their interactions. This sheds light on better seasonal influenza prediction and model construction, informing targeted prevention strategies and ultimately reducing the global burden of seasonal influenza., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Introduction: Baloxavir marboxil (BXM), a newly developed cap-dependent endonuclease inhibitor, is widely used to treat influenza virus infections in inpatients and outpatients. A previous meta-analysis included only outpatients and patients suspected of having an influenza virus infection based on clinical symptoms. However, whether BXM or oseltamivir is safer and more effective for inpatients remains controversial. Therefore, we conducted a systematic review and meta-analysis validating the effectiveness and safety of BXM versus oseltamivir in inpatients with influenza virus., Methods: The Scopus, EMBASE, PubMed, Ichushi, and CINAHL databases were systematically searched for articles published until January 2023. The outcomes were mortality, hospitalization period, incidence of BXM- or oseltamivir-related adverse events, illness duration, and changes of virus titers and viral RNA load in patients with influenza virus infections., Results: Two randomized controlled trials with 1624 outpatients and two retrospective studies with 874 inpatients were enrolled. No deaths occurred in outpatients treated with BXM or oseltamivir. Among inpatients, BXM reduced mortality (p = 0.06) and significantly shortened hospitalization period (p = 0.01) compared to oseltamivir. In outpatients, BXM had a significantly lower incidence of adverse events (p = 0.03), reductions in influenza virus titers (p < 0.001) and viral RNA loads (p < 0.001), and a tendency to be a shorter illness duration compared with that of oseltamivir (p = 0.27)., Conclusions: Our meta-analysis showed that BXM was safer and more effective in patients than oseltamivir; thus, supporting the use of BXM for the initial treatment of patients with proven influenza virus infection., Competing Interests: Declaration of competing interest None of the authors have financial and non-financial competing interests., (Copyright © 2023 Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Infection Prevention and Control. Published by Elsevier Ltd. All rights reserved.)

Neuraminidase inhibitors (NAIs) are recommended for influenza treatment and prevention worldwide. The most widely prescribed NAI is oral oseltamivir, while inhaled zanamivir is less commonly used. Using phenotypic neuraminidase (NA) enzymatic assays and molecular modeling approaches, we examined the ability of the investigational orally-dosed NAI AV5080 to inhibit viruses of the influenza A(H1N1)pdm09, A(H3N2), A(H5N1), and A(H7N9) subtypes and the influenza B/Victoria- and B/Yamagata-lineages containing NA substitutions conferring oseltamivir or zanamivir resistance including: NA-R292K, NA-E119G/V, NA-H274Y, NA-I122L/N, and NA-R150K. Broadly, AV5080 showed enhanced in vitro efficacy when compared with oseltamivir and/or zanamivir. Reduced AV5080 inhibition was determined for influenza A viruses with NA-E119G and NA-R292K, and for B/Victoria-lineage viruses with NA-I122N/L and B/Yamagata-lineage virus with NA-R150K. Molecular modeling suggested loss of the short hydrogen bond to the carboxyl group of AV5080 affected inhibition of NA-R292K viruses, whereas loss of the salt bridge with the guanidine group of AV5080 affected inhibition of NA-E119G. The resistance profiles and predicted binding modes of AV5080 and zanamivir are most similar, but dissimilar to those of oseltamivir, in part because of a guanidine moiety compensatory binding effect. Overall, our data suggests that AV5080 is a promising orally-dosed NAI that exhibited similar or superior in vitro efficacy against viruses with reduced or highly reduced inhibition phenotypes with respect to currently approved NAIs., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:A.A.I. and A.V.I. are the founders of ChemDiv, managing members of ASAVI LCC. A.V.I. is the author of patent application US 8895613. All other authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

The outbreak of the COVID-19 pandemic one year after the centennial of the 1918 influenza pandemic reaffirms the catastrophic impact respiratory viruses can have on global health and economy. A key feature of SARS-CoV-2 and influenza A viruses (IAV) is their remarkable ability to suppress or dysregulate human immune responses. Here, we summarize the growing knowledge about the interplay of SARS-CoV-2 and antiviral innate immunity, with an emphasis on the regulation of type-I or -III interferon responses that are critically implicated in COVID-19 pathogenesis. Furthermore, we draw parallels to IAV infection and discuss shared innate immune sensing mechanisms and the respective viral countermeasures., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Objectives: Because of the spread of the Omicron variant, many countries have experienced COVID-19 case numbers unseen since the start of the pandemic. We aimed to compare the epidemiological characteristics of Omicron with previous variants and different strains of influenza to provide context for public health responses., Methods: We developed transmission models for SARS-CoV-2 variants and influenza, in which transmission, death, and vaccination rates were taken to be time-varying. We fit our model based on publicly available data in South Africa, the United States, and Canada. We used this model to evaluate the relative transmissibility and mortality of Omicron compared with previous variants and influenza., Results: We found that Omicron is more transmissible and less fatal than both seasonal and 2009 H1N1 influenza and the Delta variant; these characteristics make Omicron epidemiologically more similar to influenza than it is to Delta. We estimate that as of February 7, 2022, booster doses have prevented 4.29×10 7 and 1.14×10 6 Omicron infections in the United States and Canada, respectively., Conclusion: Our findings indicate that the high infectivity of Omicron will keep COVID-19 endemic, similar to influenza. However, because of Omicron's lower fatality rate, our work suggests that human populations living with SARS-CoV-2 are most likely., Competing Interests: Declaration of Competing Interest The authors have no conflicts of interest to declare., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Influenza viruses are major human pathogens, responsible for respiratory diseases affecting millions of people worldwide, with high morbidity and significant mortality. Infections by influenza can be controlled by vaccines and antiviral drugs. However, this virus is constantly under mutations, limiting the effectiveness of these clinical antiviral strategies. It is therefore urgent to develop new ones. Influenza hemagglutinin (HA) is involved in receptor binding and promotes the pH-dependent fusion of viral and cell endocytic membranes. HA-targeted peptides may emerge as a novel antiviral option to block this viral entry step. In this study, we evaluated three HA-derived (lipo)peptides using fluorescence spectroscopy. Peptide membrane interaction assays were performed at neutral and acidic pH to better resemble the natural conditions in which influenza fusion occurs. We found that peptide affinity towards membranes decreases upon the acidification of the environment. Therefore, the released peptides would be able to bind their complementary domain and interfere with the six-helix bundle formation necessary for viral fusion, and thus for the infection of the target cell. Our results provide new insight into molecular interactions between HA-derived peptides and cell membranes, which may contribute to the development of new influenza virus inhibitors., (Copyright © 2021 Elsevier B.V. All rights reserved.)

It is more than 20 years since the neuraminidase inhibitors, oseltamivir and zanamivir were approved for the treatment and prevention of influenza. Guidelines for global surveillance and methods for evaluating resistance were established initially by the Neuraminidase Inhibitor Susceptibility Network (NISN), which merged 10 years ago with the International Society for influenza and other Respiratory Virus Diseases (isirv) to become the isirv-Antiviral Group (isirv-AVG). With the ongoing development of new influenza polymerase inhibitors and recent approval of baloxavir marboxil, the isirv-AVG held a closed meeting in August 2019 to discuss the impact of resistance to these inhibitors. Following this meeting and review of the current literature, this article is intended to summarize current knowledge regarding the clinical impact of resistance to polymerase inhibitors and approaches for surveillance and methods for laboratory evaluation of resistance, both in vitro and in animal models. We highlight limitations and gaps in current knowledge and suggest some strategies for addressing these gaps, including the need for additional clinical studies of influenza antiviral drug combinations. Lessons learned from influenza resistance monitoring may also be helpful for establishing future drug susceptibility surveillance and testing for SARS-CoV-2., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Viral respiratory tract infections have significantly impacted global health as well as socio-economic growth. Respiratory viruses such as the influenza virus, respiratory syncytial virus (RSV), and the recent SARS-CoV-2 infection (COVID-19) typically infect the upper respiratory tract by entry through the respiratory mucosa before reaching the lower respiratory tract, resulting in respiratory disease. Generally, vaccination is the primary method in preventing virus pathogenicity and it has been shown to remarkably reduce the burden of various infectious diseases. Nevertheless, the efficacy of conventional vaccines may be hindered by certain limitations, prompting the need to develop novel vaccine delivery vehicles to immunize against various strains of respiratory viruses and to mitigate the risk of a pandemic. In this review, we provide an insight into how polymer-based nanoparticles can be integrated with the development of vaccines to effectively enhance immune responses for combating viral respiratory tract infections., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: The purpose of our experiment is to discuss the function of DNA methylation and single nucleotide polymorphism (SNP) in C-X-C motif chemokine ligand 14 (CXCL14) promoter region in influenza A (H1N1) severity., Methods: Clinic data and blood samples from H1N1 patients were collected. Blood routine indexes were measured. Levels of T lymphocytes were assessed. Importantly, CXCL14 expression and methylation in H1N1 patients and A549 cells were detected through functional assays. Additionally, rs2237061, rs2237062 and rs2547 of CXCL14 were genotyped to analyze the relation of CXCL14 SNP and H1N1 severity., Results: The number of leukocytes, neutrophils and lymphocytes as well as T lymphocytes in H1N1 patients was lower than that in healthy subjects, and that was decreased in severe H1N1 patients compared with the mild H1N1 patients. In HIN1 patients, CXCL14 expression was decreased, while CXCL14 methylation was increased, and CXCL14 expression was further decreased and CXCL14 methylation was further increased in severe H1N1 patients. CXCL14 methylation was negatively correlated with T lymphocytes in H1N1 patients. CXCL14 methylation was elevated in H1N1-infected A549 cells. GA and AA genotypes of rs2547 in CXCL14 were risky genotypes for H1N1, and AA genotype was risky genotype for severe H1N1. Number of T lymphocytes was lower in H1N1 patients carrying AA genotype of rs2547 than that in GA + GG genotype., Conclusion: CXCL14 promoter region DNA methylation and SNP were correlated with H1N1 severity., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Although the virological and clinical efficacies of baloxavir for influenza and the post-treatment emergence of variant viruses have been reported in clinical trials, its efficacies have not been fully investigated in clinical settings. This prospective, observational investigator-initiated study was conducted during the 2019-2020 Japanese influenza season. In outpatients receiving baloxavir or oseltamivir, nasopharyngeal samples were obtained on day 1 before treatment and on the scheduled days 5 and 10 after treatment. RT-PCR and sequencing were performed to detect polymerase acidic protein (PA) E23X/I38X and neuraminidase (NA) H275Y variants in clinical and cultivated samples. Fever and illness-related symptoms were recorded using self-reporting diaries. Overall, 116 outpatients, 76 treated with baloxavir (34 under 12 years) and 40 with oseltamivir (32 under 12 years), were eligible. Of these, 91 were infected with A (H1N1)pdm09 (78.4%), of which 58 received baloxavir and 33 received oseltamivir. PA variants were detected in clinical (1.7%, 1/58; 3.8%, 1/26 for children under 12 years) and isolated (3.4%, 2/58; 3.8%, 1/26 for children under 12 years) samples obtained on day 5 after baloxavir treatment, but not on day 10. The isolation frequencies of A (H1N1)pdm09 on days 5 and 10 after baloxavir treatment were 5.2% (3/58) and 0.0% (0/58), respectively. Of the three viruses isolated on day 5, two (66.7%, 2/3) were PA I38 T/F variants with reduced baloxavir susceptibility. The isolation frequencies of A (H1N1)pdm09 on days 5 and 10 after oseltamivir treatment were 30.3% (10/33) and 6.1% (2/33), respectively. Only the two viruses isolated on day 10 were NA H275Y variants. The median duration of fever in baloxavir and oseltamivir recipients was 22.3 and 27.5 h, respectively. No patients with PA or NA variants showed prolonged durations of fever. Baloxavir was virologically effective for influenza in the clinical setting of the 2019-2020 Japanese season. Variant emergence after baloxavir treatment was limited to the early post-treatment stage., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)

Virus-induced cytokine storm has been a devastating actuality in clinic. The abnormal production of type I interferon (IFN-1) and upregulation of multiple cytokines induced strong inflammation and thus lead to shock and organ failure. As an E3 ubiquitin ligase, tripartite motif-containing 37 (TRIM37) regulates the ubiquitination of multiple proteins including TRAFs. RNA sequencing was performed to investigated the alteration of transcriptional profile of H1N1-infected patients. qRT-PCR assay was performed to investigate the RNA levels of certain genes. The group of immune cells was examined by the Flow cytometry analysis. H&E staining was applied to evaluate lung inflammation of WT and TRIM37-KO mice. ELISA assay was performed to demonstrate the alteration of multiple cytokines. The protein levels in NF-kB signaling was estimated by western blotting and immunoprecipitation assays were applied to demonstrate the direct interaction between TRIM37 and TRAF-6. The RNA level of TRIM37 decreased in CD11b + cells of Flu-infected patients. Knockout of TRIM37 inhibited the immune responses of H1N1-infected mice. TRIM37 deficiency reduced the levels of virous proinflammatory cytokines in bone marrow derived macrophages (BMDMs). Mechanically, TRIM37 promoted the K63-linked ubiquitination of TRAF6. TRIM37 negatively regulated inflammatory responses induced by virus infection via promoting TRAF6 ubiquitination at K63., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Influenza A viruses (IAV) are a major burden for human health and thus the topic of intense research efforts. The entry of IAV into host cells is of particular interest as early infection steps are the ideal target for intervention strategies. Here, we review recent key findings in the field of IAV entry. Specifically, we discuss the identification of novel entry receptors, the emerging role of the viral neuraminidase in entry, as well as recent progress from structural studies on the viral hemagglutinin during the fusion process and the viral matrix protein involved in virus uncoating. We also highlight remaining gaps in our understanding of IAV entry and point out important questions for ongoing research efforts., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Amino acid substitutions in influenza virus neuraminidase (NA) that cause resistance to neuraminidase inhibitors (NAI) generally result in virus attenuation. However, influenza viruses may acquire secondary substitutions in the NA and hemagglutinin (HA) proteins that can restore viral fitness. To assess to which extent this happens, the emergence of NAI resistance substitutions and secondary - potentially compensatory - substitutions was quantified in influenza viruses of immunocompetent individuals included in the Influenza Resistance Information Study (IRIS; NCT00884117). Known resistance substitutions were detected by mutation specific RT-PCR in viruses of 57 of 1803 (3.2%) oseltamivir-treated individuals, including 39 individuals infected with A/H1N1pdm09 [H275Y] virus and 18 with A/H3N2 [R292K] virus. A total of fifteen and ten other amino acid substitutions were acquired in HA and NA respectively, of A/H1N1pdm09, A/H3N2 and influenza B viruses upon treatment with oseltamivir but none of these was associated with resistance to oseltamivir. All cultured viruses with the known resistance substitutions H275Y or R292K showed reduced susceptibility to oseltamivir in the NA-star assay. Upon next-generation sequencing, the vast majority of NAI resistant A/H1N1pdm09 and A/H3N2 viruses had no resistance-associated secondary substitutions at high frequency. Only in two A/H1N1pdm09 [H275Y] viruses, the potentially compensatory secondary substitutions HA-D52N and NA-R152K were detected. We conclude that the emergence of secondary substitutions that may restore viral fitness upon the emergence of known influenza virus NAI resistance substitutions was a rare event in this immunocompetent population., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Adverse pregnancy outcomes are risk factors for neonatal mortality and morbidity. While some studies have demonstrated notable associations between influenza and adverse pregnancy outcomes, the findings have contrasted with other studies. This meta-analysis was conducted to assess the effect of influenza infection on pregnancy outcomes., Methods: We searched PubMed, Embase, Cochrane Library and Web of Science from inception to 4 November 2020. Relative risks (RRs) with 95% confidence intervals (CIs) were pooled using random-effects or fixed-effects models., Results: A total of 17 studies involving 2,351,204 participants were included. Influenza infection increased the risk of stillbirth (RR = 3.62, 95% CI: 1.60-8.20), with no significant effect on preterm birth (RR = 1.17, 95%CI: 0.95-1.45), fetal death (RR = 0.93, 95%CI: 0.73-1.18), small for gestational age (SGA) (RR = 1.10, 95%CI: 0.98-1.24) and low birth weight (LBW) (RR = 1.88, 95%CI: 0.46-7.66). In a subgroup analysis of LBW, the association was evident in studies conducted during the 2009 H1N1 pandemic (RR = 2.28, 95%CI: 1.81-2.87), with no evidence of an association in pre-pandemic or post-pandemic studies., Conclusions: Influenza virus infection was associated with an increased risk of stillbirth, but its effect on preterm birth, fetal death, SGA and LBW is still uncertain., Competing Interests: Declaration of Competing Interest The authors report no declarations of interest., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Pimodivir exerts an antiviral effect on the early stages of influenza A virus replication by inhibiting the cap-binding function of polymerase basic protein 2 (PB2). In this study, we used a combination of sequence analysis and phenotypic methods to evaluate pimodivir susceptibility of influenza A viruses collected from humans and other hosts. Screening PB2 sequences for substitutions previously associated with reduced pimodivir susceptibility revealed a very low frequency among seasonal viruses circulating in the U.S. during 2015-2020 (<0.03%; 3/11,934) and among non-seasonal viruses collected in various countries during the same period (0.2%; 18/8971). Pimodivir potently inhibited virus replication in two assays, a single-cycle HINT and a multi-cycle FRA, with IC 50 values in a nanomolar range. Median IC 50 values determined by HINT were similar for both subtypes of seasonal viruses, A(H1N1)pdm09 and A(H3N2), across three seasons. Human seasonal viruses with PB2 substitutions S324C, S324R, or N510K displayed a 27-317-fold reduced pimodivir susceptibility by HINT. In addition, pimodivir was effective at inhibiting replication of a diverse group of animal-origin viruses that have pandemic potential, including avian viruses of A(H5N6) and A(H7N9) subtypes. A rare PB2 substitution H357N was identified in an A(H4N2) subtype poultry virus that displayed >100-fold reduced pimodivir susceptibility. Our findings demonstrate a broad inhibitory activity of pimodivir and expand the existing knowledge of amino acid substitutions that can reduce susceptibility to this investigational antiviral., (Published by Elsevier B.V.)

Objective: We aimed to evaluate the clinical and epidemiological behavior of influenza type A versus type B and analyze if there was any correlation or differences between the characteristics of both groups., Methods: An observational, retrospective, descriptive, and population-based study based of children who were hospitalized at the only national pediatric hospital of Costa Rica from January 1, 2010 to December 31, 2018 and had a confirmed influenza virus infection., Results: 336 patients were analyzed. Mean age was 35,6 ± 36,7 months (3,0 ± 3,1 years). The only significant variables at 25% in relation to influenza type A or B virus were: sex, month of diagnosis, fever, vomiting, cough, use of antibiotics and admission to the PICU. The hospitalization rate at our hospital increased between the months of October to December, with a higher percentage of cases in November and December, which reveals that the "real peak" in our population begins between 3 to 4 months after the end of the vaccination campaign. Patients with influenza A virus had a 2.5 times greater risk of being admitted to the PICU. Mortality rate was 0.6% and 0% among influenza A and B children, respectively., Conclusions: Variables in which a causality was found with type A or B virus were: admission to the PICU, month of diagnosis, and cough. However, influenza B clinical behavior continues to be unpredictable., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Quantum dots (QDs) based fluorescent nanobeads are considered as promising materials for next generation point-of-care diagnosis systems. In this study, we carried out, for the first time, the synthesis of QDs nanobeads using polystyrene (PS) nanobead as the template. QDs loading on PS nanobead surface in this method can be readily achieved by the use of polyelectrolyte, avoiding the time-consuming and uncontrollable silane reagents-involved functionalization procedure that conventional synthesis of silica-based QDs nanobeads often suffer from. Notably, the application of QDs nanobeads in suspension microarray for H5N1 virus detection leads to a sensitivity lower than 25 PFU/mL. In addition, QDs nanobead was also incorporated into lateral flow assay for SARS-CoV-2 antibody detection, leading to more than one order of magnitude detection sensitivity as compared to that of commercial one based on colloid gold., (Copyright © 2021 Elsevier B.V. All rights reserved.)