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The high genetic diversity of influenza viruses means that traditional serological assays have too low throughput to measure serum antibody neutralization titers against all relevant strains. To overcome this challenge, we developed a sequencing-based neutralization assay that simultaneously measures titers against many viral strains using small serum volumes using a workflow similar to traditional neutralization assays. The key innovation is to incorporate unique nucleotide barcodes into the hemagglutinin (HA) genomic segment, and then pool viruses with numerous different barcoded HA variants and quantify the infectivity of all of them simultaneously using next-generation sequencing. With this approach, a single researcher performed the equivalent of 2,880 traditional neutralization assays (80 serum samples against 36 viral strains) in approximately 1 month. We applied the sequencing-based assay to quantify the impact of influenza vaccination on neutralization titers against recent human H1N1 strains for individuals who had or had not also received a vaccine in the previous year. We found that the viral strain specificities of the neutralizing antibodies elicited by vaccination vary among individuals and that vaccination induced a smaller increase in titers for individuals who had also received a vaccine the previous year--although the titers 6 months after vaccination were similar in individuals with and without the previous-year vaccination. We also identified a subset of individuals with low titers to a subclade of recent H1N1 even after vaccination. We provide an experimental protocol (dx.doi.org/10.17504/protocols.io.kqdg3xdmpg25/v1) and computational pipeline (https://github.com/jbloomlab/seqneut-pipeline) for the sequencing-based neutralization assays to facilitate the use of this method by others. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusions Immune dysregulation and SARS‐CoV‐2 plasma viremia have been implicated in fatal COVID‐19 disease. However, how these two factors interact to shape disease outcomes is unclear.We carried out viral and immunological phenotyping on a prospective cohort of 280 patients with COVID‐19 presenting to acute care hospitals in Boston, Massachusetts and Genoa, Italy between June 1, 2020 and February 8, 2022. Disease severity, mortality, plasma viremia, and immune dysregulation were assessed. A mouse model of lethal H1N1 influenza infection was used to analyze the therapeutic potential of Notch4 and pyroptosis inhibition in disease outcome.Stratifying patients based on %Notch4+ Treg cells and/or the presence of plasma viremia identified four subgroups with different clinical trajectories and immune phenotypes. Patients with both high %Notch4+ Treg cells and viremia suffered the most disease severity and 90‐day mortality compared to the other groups even after adjusting for baseline comorbidities. Increased Notch4 and plasma viremia impacted different arms of the immune response in SARS‐CoV‐2 infection. Increased Notch4 was associated with decreased Treg cell amphiregulin expression and suppressive function whereas plasma viremia was associated with increased monocyte cell pyroptosis. Combinatorial therapies using Notch4 blockade and pyroptosis inhibition induced stepwise protection against mortality in a mouse model of lethal H1N1 influenza infection.The clinical trajectory and survival outcome in hospitalized patients with COVID‐19 is predicated on two cardinal factors in disease pathogenesis: viremia and Notch4+ Treg cells. Intervention strategies aimed at resetting the immune dysregulation in COVID‐19 by antagonizing Notch4 and pyroptosis may be effective in severe cases of viral lung infection. [ABSTRACT FROM AUTHOR]

Background: Swine flu might serve as a model for challenges that primary care faces during pandemics. This study examined changes in the numbers and diagnoses of general practitioner (GP) visits during and after the Swine flu pandemic in Vantaa, a Finnish city, and how GP activities recovered after the pandemic. Putative sex and age group differences were also evaluated. Methods: The study was an observational retrospective study. The monthly number of patient visits to primary care GPs by women and men in age groups 0–19, 20–64 and 65 + years was recorded before, during and two years after the Swine flu pandemic. The recorded diagnoses were also examined. The investigation period was from 2008 to 2012. Results: The numbers of monthly visits to primary care decreased from 12 324 (mean) to 10 817 in women and from 8563 to 7612 in men during the first six months of the Swine flu, returning to the original level afterwards. This decrease was thus slightly more prominent in women. However, as the size of the population increased during the follow-up period, the actual number of GP visits adjusted for the size of population remained at a decreased level for two years after the Swine flu. This decrease was observed especially in office-hours visits of men (from 3692 to 3260) and women (from 6301 to 5428) of 20–64 years. Swine flu did not alter the number of visits to the primary care Emergency Department. The proportion of visits with diagnostic recordings of common infectious diseases mostly decreased during the Swine flu. Only a minor impact on the distribution of recordings of chronic diagnoses was found. Conclusion: A pandemic, such as Swine flu, may decrease office-hours visits to primary care GPs. This in turn may lead to activities of primary care being adjusted downward for a long time following the pandemic. Especially the age group 20–64 years may be affected. This risk should be considered when recovery from the COVID-19 pandemic begins. Swine flu did not affect the proportion of consultations of chronic diseases, but the number of diagnoses of common infectious diseases had diminished. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 24-year-old man who was admitted with fever, cough, shortness of breath, and chest pain, ultimately diagnosed with a respiratory viral infection, likely influenza, complicated by a bacterial superinfection. Topics discussed include the historical context of the 1918 influenza pandemic, advancements in the identification and vaccination against influenza, and the development of early surveillance systems and their impact on public health responses.

Background: Dogs in close contact with humans can serve as a source of potentially dangerous reassortant influenza viruses (IVs) with zoonotic potential. The dog’s body can serve as a vessel for the emergence of new IVs. These new viruses can become a source of infection for other animals and humans. The potential for zoonotic transmission of IVs from dogs to humans poses a public health risk. Aim: Study of the circulation of IVs in the dog population in Almaty, Kazakhstan. Methods: Biosamples (oropharyngeal swabs and blood serum) from dogs were collected from veterinary clinics in Almaty in 2023–2024. Samples were screened using RT-PCR, HI assay, and ELISA. Results: RT-PCR analysis of 355 nasopharyngeal swabs showed the presence of influenza A virus (IAV) in 32 samples (9.01% of the total number of samples analyzed). When subtyping IAV H1N1 RNA was detected in 19 swabs (5.35%). IAV subtype could not be determined in 13 PCR-positive samples (3.66%). The genetic material of IAV H3N2, H5, H7, and H9, as well as coronavirus, bocavirus, and adenovirus has not been identified. In a serological analysis of 180 blood sera using ELISA, antibodies to IAV were detected in 5.56% (n = 10). The results of the HI assay showed the presence of antihemagglutinins to A/H1N1pdm in 6.11% (11 samples), to A/H3N2 in 9.44% (17 samples), and no antibodies to IAV H5, H7, and type B were detected. Conclusion: There is no information about human infection with any canine influenza virus. However, many cases of infection in dogs with human IAVs H1N1, H1N1pdm09, and H3N2 have been described. When dogs are co-infected with different IAVs, new recombinant IAVs may emerge that can infect humans and other animals. Therefore, ongoing global surveillance of animal populations is necessary to monitor the evolution and circulation of viruses dangerous to public health. This is also important for timely preparation for the emergence of a new zoonotic influenza virus that has pandemic potential for humans. [ABSTRACT FROM AUTHOR]

The CRISPR-Cas13 system has been proposed as an alternative treatment of viral infections. However, for this approach to be adopted as an antiviral, it must be optimized until levels of efficacy rival or exceed the performance of conventional approaches. To take steps toward this goal, we evaluated the influenza viral RNA degradation patterns resulting from the binding and enzymatic activity of mRNA-encoded LbuCas13a and two crRNAs from a prior study, targeting PB2 genomic and messenger RNA. We found that the genome targeting guide has the potential for significantly higher potency than originally detected, because degradation of the genomic RNA is not uniform across the PB2 segment, but it is augmented in proximity to the Cas13 binding site. The PB2 genome targeting guide exhibited high levels (>1 log) of RNA degradation when delivered 24 hours post-infection in vitro and maintained that level of degradation over time, with increasing multiplicity of infection (MOI), and across modern influenza H1N1 and H3N2 strains. Chemical modifications to guides with potent LbuCas13a function, resulted in nebulizer delivered efficacy (>1–2 log reduction in viral titer) in a hamster model of influenza (Influenza A/H1N1/California/04/09) infection given prophylactically or as a treatment (post-infection). Maximum efficacy was achieved with two doses, when administered both pre- and post-infection. This work provides evidence that mRNA-encoded Cas13a can effectively mitigate Influenza A infections opening the door to the development of a programmable approach to treating multiple respiratory infections. Author summary: For the CRISPR-Cas13 system to be adopted as an alternative treatment of viral infections, it must reach levels of efficacy that rival or exceed the performance of conventional approaches. We evaluated the degradation patterns resulting from the binding and enzymatic activity of mRNA-encoded LbuCas13a and two previously identified crRNAs, targeting conserved PB2 genomic and messenger RNA sequences. The genome targeting guide displayed higher potency than originally detected, because RNA degradation was augmented near the guide binding site, leading to 1-log of RNA degradation in vitro, which persisted over time, with increasing multiplicity of infection (MOI), and across modern influenza H1N1 and H3N2 strains. The addition of chemical modifications to the guide resulted in 1-2-log reduction in viral titer upon nebulizer delivery prophylactically or as a treatment in a hamster model of influenza. Maximum efficacy was achieved with two doses administered pre- and post-infection. [ABSTRACT FROM AUTHOR]

Influenza A virus subtype H1N1 can cause severe acute respiratory distress syndrome and death in young children and elderly individuals. H1N1 initiates inflammatory responses that aim to contain and eliminate microbial invaders. Various lipid mediators (LMs) are biosynthesized and play a critical role in fighting viruses during inflammation; thus, by profiling the LMs in patients, researchers can obtain mechanistic insights into diseases, such as the pathways disrupted. To date, the relationship between molecular alterations in LMs and the pathogenesis of H1N1 influenza in children is poorly understood. Here, we employed a targeted liquid chromatography coupled with tandem mass spectrometry (LC‒MS/MS) to profile LMs in serum from children with H1N1 influenza (H1N1 children) and recovered children. We found that 22 LM species were altered in H1N1 children with mild symptoms. Analysis of the LM profiles of recovered children revealed a decrease in the levels of thromboxane B2 (TxB2) and thromboxane B3 (TxB3) and an increase in the levels of other 8 altered LM species associated with H1N1 influenza, including cytochrome P450 (CYP) enzyme-derived dihydroxyeicosatrienoic acids (DiHETrEs) and hydroxyeicosatetraenoic acids (HETEs) from arachidonic acid (AA), and epoxyoctadecamonoenoic acids (EpOMEs) from linoleic acid (LA). Taken together, the results of this study revealed that serum LMs change dynamically in H1N1 children with mild symptoms. The dramatically altered LMs in H1N1 children could serve as a basis for potential therapeutics or adjuvants against H1N1 influenza. [ABSTRACT FROM AUTHOR]

Surprisingly, the 1977 "Russian flu" H1N1 pandemic influenza virus was genetically indistinguishable from strains that had circulated decades earlier but had gone extinct in 1957. This essay puts forward the most plausible chronology to explain the reemergence of the 1977 H1N1 pandemic virus: (1) in January–February 1976, a self-limited small outbreak of a swine H1N1 influenza virus occurred among Army personnel at Fort Dix, New Jersey; (2) in March 1976, the US launched a nationwide H1N1 swine influenza vaccine program; (3) other countries then also launched their own H1N1 R&D efforts; (4) a new H1N1 outbreak, genetically unrelated to the Fort Dix swine virus but indistinguishable from previously extinct H1N1 viruses, was detected early in 1977 in China; (5) the leading Chinese influenza virologist later disclosed that the Chinese military had conducted large H1N1 vaccine R&D studies in 1976. It is likely that the resurrected H1N1 influenza viruses were laboratory-stored strains that were unfrozen and studied as part of the emergency response to a perceived epidemic threat, and that accidentally escaped. The fear of a possible H1N1 pandemic was the critical factor that gave rise to the actual H1N1 pandemic, resulting in an avoidable "self-fulfilling prophecy pandemic." [ABSTRACT FROM AUTHOR]

Background: The MIMIX platform is a novel microneedle array patch (MAP) characterized by slowly dissolving microneedle tips that deploy into the dermis following patch application. We describe safety, reactogenicity, tolerability and immunogenicity for MIMIX MAP vaccination against influenza. Methodology: The trial was a Phase 1, exploratory, first-in-human, parallel randomized, rater, participant, study analyst-blinded, placebo-controlled study in Canada. Forty-five healthy participants (18 to 39 years of age, inclusive) were randomized in a 1:1:1 ratio to receive either 15 μg or 7.5 μg of an H1N1 influenza vaccine, or placebo delivered via MIMIX MAP to the volar forearm. A statistician used a computer program to create a randomization scheme with a block size of 3. Post-treatment follow-up was approximately 180 days. Primary safety outcomes included the incidence of study product related serious adverse events and unsolicited events within 180 days, solicited application site and systemic reactogenicity through 7 days after administration and solicited application site erythema and/or pigmentation 14, 28, 56 and 180 days after administration. Immunogenicity outcomes included antibody titers and percentage of seroconversion (SCR) and seroprotection (SPR) rates determined by the hemagglutination inhibition (HAI) assay. Exploratory outcomes included virus microneutralization (MN) titers, durability and breadth of the immune response. The trial was registered with ClinicalTrials.gov, number NCT 06125717. Findings: Between July 7, 2022 and March 13, 2023 45 participants were randomized to a treatment group. One participant was lost to follow up in the 15 μg group and 1 participant withdrew from the 7.5 μg dose group. Safety analyses included n = 15 per group, immunogenicity analyses included n = 14 for the 15 μg and 7.5 μg treatment groups and n = 15 for the placebo group. No SAEs were reported in any of the treatment groups. All treatment groups reported solicited local events within 7 days after vaccination, with mild (Grade 1) erythema being the most frequent symptom reported. Other local symptoms reported included mostly mild (Grade 1) induration/swelling, itching, pigmentation, skin flaking, and tenderness. Within 7 days after vaccination, 2 participants (4.4%) reported moderate (Grade 2) erythema, 1 participant (2.2%) reported moderate (Grade 2) induration/swelling, and 1 participant (2.2%) reported moderate (Grade 2) itching. There was an overall reduction in erythema and pigmentation reported on Days 15, 29, 57, and 180 among all treatment groups. Systemic symptoms reported within 7 days after vaccination, included mild (Grade 1) fatigue reported among all treatment groups, and mild (Grade 1) headache reported by 1 participant in the 7.5 μg treatment group. No study drug related severe symptoms were reported in the study. Group mean fold rises in HAI titers ranged between 8.7 and 12-fold, SCRs were >76% and SPRs were >92% for both VX-103 dose groups thereby fulfilling serological criteria established by the EMA and FDA for seasonal influenza vaccines. Longitudinal assessments demonstrate persistence of the immune response through at least Day 180. Conclusions: The MIMIX MAP platform is safe, well tolerated and elicits robust antibody responses. [ABSTRACT FROM AUTHOR]

Background: H1N1 is one of the major subtypes of influenza A virus (IAV) that causes seasonal influenza, posing a serious threat to human health. A traditional Chinese medicine combination called Qingxing granules (QX) is utilized clinically to treat epidemic influenza. However, its chemical components are complex, and the potential pharmacological mechanisms are still unknown. Methods: QX's effective components were gathered from the TCMSP database based on two criteria: drug-likeness (DL ≥ 0.18) and oral bioavailability (OB ≥ 30%). SwissADME was used to predict potential targets of effective components, and Cytoscape was used to create a "Herb-Component-Target" network for QX. In addition, targets associated with H1N1 were gathered from the databases GeneCards, OMIM, and GEO. Targets associated with autophagy were retrieved from the KEGG, HAMdb, and HADb databases. Intersection targets for QX, H1N1 influenza, and autophagy were identified using Venn diagrams. Afterward, key targets were screened using Cytoscape's protein–protein interaction networks built using the database STRING. Biological functions and signaling pathways of overlapping targets were observed through GO analysis and KEGG enrichment analysis. The main chemical components of QX were determined by high-performance liquid chromatography (HPLC), followed by molecular docking. Finally, the mechanism of QX in treating H1N1 was validated through animal experiments. Results: A total of 786 potential targets and 91 effective components of QX were identified. There were 5420 targets related to H1N1 and 821 autophagy-related targets. The intersection of all targets of QX, H1N1, and autophagy yielded 75 intersecting targets. Ultimately, 10 core targets were selected: BCL2, CASP3, NFKB1, MTOR, JUN, TNF, HSP90AA1, EGFR, HIF1A, and MAPK3. Identification of the main chemical components of QX by HPLC resulted in the separation of seven marker ingredients within 195 min, which are amygdalin, puerarin, baicalin, phillyrin, wogonoside, baicalein, and wogonin. Molecular docking results showed that BCL2, CASP3, NFKB1, and MTOR could bind well with the compounds. In animal studies, QX reduced the degenerative alterations in the lung tissue of H1N1-infected mice by upregulating the expression of p-mTOR/mTOR and p62 and downregulating the expression of LC3, which inhibited autophagy. Conclusions: According to this study's network pharmacology analysis and experimental confirmation, QX may be able to treat H1N1 infection by regulating autophagy, lowering the expression of LC3, and increasing the expression of p62 and p-mTOR/mTOR. [ABSTRACT FROM AUTHOR]

Onradivir (ZSP1273) is a novel anti-influenza A virus inhibitor. Preclinical studies show that onradivir can inhibit influenza A H1N1 and H3N2 replication and increase the survival rate of infected animals. In this study, we aimed to evaluate the safety and efficacy of three onradivir dosing regimens versus placebo in outpatients with acute uncomplicated influenza A virus infection. We did a multicentre, double-blind, randomised, placebo-controlled, phase 2 trial at 20 clinical sites in China. Eligible participants were adults (18–65 years) with an influenza-like illness screened by rapid antigen testing at the first clinical visit, had the presence of a fever (axillary temperature ≥38·0°C), and had the presence of at least one moderate systemic and one respiratory symptom within 48 h of symptom onset. Patients were excluded if they were pregnant, allergic to onradivir, or had received any influenza antiviral medication within 7 days before enrolment. Participants were randomly assigned (1:1:1:1) into four groups by an interactive web response system: onradivir 200 mg twice per day group, onradivir 400 mg twice per day group, onradivir 600 mg once per day group, and a matching placebo group. A 5-day oral treatment course was initiated within 48 h after symptoms onset. The primary outcome was the time to alleviate influenza symptoms in the modified intention-to-treat population. Safety was a secondary outcome. We evaluated the patients' self-assessed severity of seven influenza symptoms on a 4-point ordinal scale, and the treatment-emergent adverse events in all patients. This trial is registered with ClinicalTrials.gov , number NCT04024137. Between Dec 7, 2019, and May 18, 2020, a total of 205 patients were screened; of whom, 172 (84%) were randomly assigned to receive onradivir (n=43 in the 200 mg twice per day group; n=43 in the 400 mg twice per day group; and n=43 in the 600 mg once per day group), or placebo (n=42). Median age was 22 years (IQR 20–26). All three onradivir groups showed decreased median time to alleviate influenza symptoms (46·92 h [IQR 24·00–81·38] in the 200 mg twice per day group, 54·87 h [23·67–110·62] in the 400 mg twice per day group, and 40·05 h [17·70–65·82] in the 600 mg once per day) compared with the placebo group (62·87 h [36·40–113·25]). The median difference between the onradivir 600 mg once per day group and the placebo group was –22·82 h (p=0·0330). The most frequently reported treatment-emergent adverse event was diarrhoea (71 [42%] of 171), ranging from 33–65% of the patients in onradivir-treated groups compared with 10% in the placebo group; no serious adverse events were observed. Onradivir showed a safety profile comparable to placebo, as well as higher efficacy than placebo in ameliorating influenza symptoms and lowering the viral load in adult patients with uncomplicated influenza infection, especially the onradivir 600 mg once per day regimen. National Multidisciplinary Innovation Team Project of Traditional Chinese Medicine, National Natural Science Foundation of China, Guangdong Science and Technology Foundation, Guangzhou Science and Technology Planning Project, Emergency Key Program of Guangzhou Laboratory, Macao Science and Technology Development Fund, and Guangdong Raynovent Biotech. [ABSTRACT FROM AUTHOR]

It is hypothesized that narcolepsy type 1 (NT1) develops in genetically susceptible people who encounter environmental triggers leading to immune-mediated hypocretin-1 deficiency. The pathophysiologies of narcolepsy type 2 (NT2) and idiopathic hypersomnia (IH) remain unknown. The main aim of this study was to collect all reported immunological events before onset of a central disorder of hypersomnolence. Medical records of 290 people with NT1, and 115 with NT2 or IH were retrospectively reviewed to extract infection and influenza vaccination history. Prevalence, distribution of immunological events, and time until hypersomnolence onset were compared between NT1 and the combined group of NT2 and IH. Immunological events were frequently reported before hypersomnolence disorder onset across groups. Flu and H1N1 influenza vaccination were more common in NT1, and Epstein–Barr virus and other respiratory and non-respiratory infections in NT2 and IH. Distributions of events were comparable between NT2 and IH. Rapid symptom onset within one month of infection was frequent across groups, especially after flu infection in NT1. Hypersomnolence disorder progression after an immunological event was reported in ten individuals. Our findings suggest a variety of immunological triggers potentially related to NT1, including H1N1 influenza infection or vaccination, infection with other flu types, and other respiratory and non-respiratory infections. Frequent reports of immunological events (other than those reported in NT1) immediately prior to the development of NT2 and IH support the specificity of triggers for NT1, and open important new research avenues into possible underlying immunological mechanisms in NT2 and IH. • We studied possible immunological triggers for central disorders of hypersomnolence. • Flu and H1N1 influenza vaccination were more common before narcolepsy type 1 onset. • Non-flu infections were common before narcolepsy type 2/idiopathic hypersomnia onset. • Rapid hypersomnolence onset within one month was frequent across groups. [ABSTRACT FROM AUTHOR]

Allobetulin derivatives with rearranged E-ring exhibit important pharmacological properties against various viral pathogens. Basing on 3β-acetoxy-21β-acetyl-20β,28-epoxy-18α,19βH-ursane triterpenoid, obtained from allobetulin in one stage, a series of new derivatives have been synthesized and their antiviral activity against both influenza virus A (H1N1) and SARS-CoV-2 pseudovirus was evaluated. Among them, 2,3-indolo-allobetulone N-propargyl derivatives were the most efficacious against influenza virus with low toxicity (CC50 × 300 μM) and IC50 values of 7.04 to 3.5 μM and high selectivity indexes (SI 43 and 86). Compared with amodiaquine, a derivative with 3-pyridinylidene fragment 12 showed a weak antiviral activity against SARS-CoV-2 pseudovirus with an inhibition rate of 57.3% at a concentration of 20 μM. Further optimization to increase the cellular antiviral activity seems to be necessary to develop this series of triterpenoids as antiviral agents. [ABSTRACT FROM AUTHOR]

Influenza remains one of the most serious infectious diseases. Gallic acid is one of the most common and representative phenolic acids found in various plants. This is an interesting subject to explore how gallic acid could inhibit H1N1 influenza virus infection by reducing the production of virulent proteins and interrupting autophagy machinery for influenza virus replication on the host cell. Cellular viability was assessed by XTT assay. The inhibitory effects on the H1N1 influenza virus were assessed by hemagglutination assay, plaque assay, and qRT‐PCR. Western blot analysis was used for detecting protein levels of M1, M2, NP, LC3B, and beclin‐1. Autophagy activity was demonstrated by acridine orange staining assay. The result demonstrated that there was no cytotoxic effect of gallic acid on A549 cells, and gallic acid could restore the cellular viability of H1N1 influenza virus‐infected A549 cells within the experimental concentration treatment. Moreover, gallic acid could effectively restrain viral activity of the H1N1 influenza virus. After the treatment of gallic acid, the production of virulent H1N1 influenza virus proteins, that is, M1, M2, and NP protein were reduced. As for autophagic mechanism, both of the LC3B II conversion and the level ratio of LC3B II to LC3B I were notably decreased. The acridine orange staining assay also revealed decreased accumulation of autophagosomes in H1N1 influenza virus‐infected cells. In conclusion, gallic acid suppresses H1N1 influenza viral infectivity through restoration of autophagy pathway and inhibition of virulent M1, M2, and NP protein production. [ABSTRACT FROM AUTHOR]

The increased detection of H3 C-IVA (1990.4.a) clade influenza A viruses (IAVs) in US swine in 2019 was associated with a reassortment event to acquire an H1N1pdm09 lineage nucleoprotein (pdmNP) gene, replacing a TRIG lineage NP (trigNP). We hypothesized that acquiring the pdmNP conferred a selective advantage over prior circulating H3 viruses with a trigNP. To investigate the role of NP reassortment in transmission, we identified two contemporary 1990.4.a representative strains (NC/19 and MN/18) with different evolutionary origins of the NP gene. A reverse genetics system was used to generate wild-type (wt) strains and swap the pdm and TRIG lineage NP genes, generating four viruses: wtNC/19-pdmNP, NC/19-trigNP, wtMN/18-trigNP, and MN/18-pdmNP. The pathogenicity and transmission of the four viruses were compared in pigs. All four viruses infected 10 primary pigs and transmitted to five indirect contact pigs per group. Pigs infected via contact with MN/18-pdmNP shed virus 2 days earlier than pigs infected with wtMN/18-trigNP. The inverse did not occur for wtNC/19-pdmNP and NC/19-trigNP. This suggests that pdmNP reassortment resulted in a combination of genes that improved transmission efficiency when paired with the 1990.4.a hemagglutinin (HA). This is likely a multigenic trait, as replacing the trigNP gene did not diminish the transmission of a wild-type IAV in swine. This study demonstrates how reassortment and evolutionary change of internal genes can result in more transmissible viruses that influence HA clade detection frequency. Thus, rapidly identifying novel reassortants paired with dominant hemagglutinin/neuraminidase may improve the prediction of strains to include in vaccines. [ABSTRACT FROM AUTHOR]

Seasonal infection rates of individual viruses are influenced by synergistic or inhibitory interactions between coincident viruses. Endemic patterns of SARS-CoV-2 and influenza infection overlap seasonally in the Northern hemisphere and may be similarly influenced. We explored the immunopathologic basis of SARS-CoV-2 and influenza A (H1N1pdm09) interactions in Syrian hamsters. H1N1 given 48 h prior to SARS-CoV-2 profoundly mitigated weight loss and lung pathology compared to SARS-CoV-2 infection alone. This was accompanied by the normalization of granulocyte dynamics and accelerated antigen-presenting populations in bronchoalveolar lavage and blood. Using nasal transcriptomics, we identified a rapid upregulation of innate and antiviral pathways induced by H1N1 by the time of SARS-CoV-2 inoculation in 48 h dual-infected animals. The animals that were infected with both viruses also showed a notable and temporary downregulation of mitochondrial and viral replication pathways. Quantitative RT-PCR confirmed a decrease in the SARS-CoV-2 viral load and lower cytokine levels in the lungs of animals infected with both viruses throughout the course of the disease. Our data confirm that H1N1 infection induces rapid and transient gene expression that is associated with the mitigation of SARS-CoV-2 pulmonary disease. These protective responses are likely to begin in the upper respiratory tract shortly after infection. On a population level, interaction between these two viruses may influence their relative seasonal infection rates. [ABSTRACT FROM AUTHOR]

Background: Despite their higher risk of developing severe disease, little is known about the burden of influenza in Portugal in children aged < 5 years old. This study aims to cover this gap by estimating the clinical and economic burden of severe influenza in children, in Portugal, during ten consecutive influenza seasons (2008/09-2017/18). Methods: We reviewed hospitalizations in children aged < 5 years old using anonymized administrative data covering all public hospitals discharges in mainland Portugal. The burden of hospitalization and in-hospital mortality directly coded as due to influenza was supplemented by the indirect burden calculated from excess hospitalization and mortality (influenza-associated), estimated for four groups of diagnoses (pneumonia or influenza, respiratory, respiratory or cardiovascular, and all-cause), through cyclic regression models integrating the incidence of influenza. Means were reported excluding the H1N1pdm09 pandemic (2009/10). Results: The mean annual number of hospitalizations coded as due to influenza was 189 (41.3 cases per 100,000 children aged < 5 years old). Hospitalization rates decreased with increasing age. Nine-in-ten children were previously healthy, but the presence of comorbidities increased with age. Children stayed, on average, 6.1 days at the hospital. Invasive mechanical ventilation was used in 2.4% of hospitalizations and non-invasive in 3.1%. Influenza-associated excess hospitalizations between 2008 and 2018 were estimated at 1,850 in pneumonia or influenza, 1,760 in respiratory, 1,787 in respiratory or cardiovascular, and 1,879 in all-cause models. A total of 95 influenza-associated excess deaths were estimated in all-cause, 14 in respiratory or cardiovascular, and 9 in respiratory models. Over ten years, influenza hospitalizations were estimated to have cost the National Health Service at least €2.9 million, of which 66.5% from healthy children. Conclusions: Influenza viruses led to a high number of hospitalizations in children. Most were previously healthy. Results should lead to a reflection on the adequate preventive measures to protect this age group. [ABSTRACT FROM AUTHOR]

Influenza pandemic with H1N1 (H1N1pdms) causes severe lung damage and "cytokine storm," leading to higher mortality and global health emergencies in humans and animals. Explaining host antiviral molecular mechanisms in response to H1N1pdms is important for the development of novel therapies. In this study, we organised and analysed multimicroarray data for mouse lungs infected with different H1N1pdm and nonpandemic H1N1 strains. We found that H1N1pdms infection resulted in a large proportion of differentially expressed genes (DEGs) in the infected lungs compared with normal lungs, and the number of DEGs increased markedly with the time of infection. In addition, we found that different H1N1pdm strains induced similarly innate immune responses and the identified DEGs during H1N1pdms infection were functionally concentrated in defence response to virus, cytokine-mediated signalling pathway, regulation of innate immune response, and response to interferon. Moreover, comparing with nonpandemic H1N1, we identified ten distinct DEGs (AREG, CXCL13, GATM, GPR171, IFI35, IFI47, IFIT3, ORM1, RETNLA, and UBD), which were enriched in immune response and cell surface receptor signalling pathway as well as interacted with immune response-related dysregulated genes during H1N1pdms. Our discoveries will provide comprehensive insights into host responding to pandemic with influenza H1N1 and find broad-spectrum effective treatment. [ABSTRACT FROM AUTHOR]

This article analyzes in a general way the relationship between the origin of the COVID-19 pandemic and industrial (mass production) animal husbandry farms (wild and domestic). The fact that the origin of SARS-CoV-2, the coronavirus that causes COVID-19 disease, has not been conclusively determined, and even though the WHO has preferentially considered the animal origin (zoonotic hypothesis), ruling out the hypothesis of the escape of the coronavirus in a laboratory, there are aspects that due to the previous history of influenza pandemics (2003 H5NI avian influenza and 2009 H1N1 swine influenza) raise the need to review the role played by transnational companies in the food chain, as well as the strategies of these companies to shape regulations in this area at their convenience. [ABSTRACT FROM AUTHOR]

Influenza virus strain A/South Africa/3626/2013 (H1N1)pdm09 (SA-WT) is a non-mouse-adapted model strain that has naturally high pathogenic properties in mice. It has been suggested that the high pathogenicity of this strain for mice could be due to the three strain-specific substitutions in the polymerase complex (Q687R in PB1, N102T in PB2, and E358E/K heterogeneity in PB2). To evaluate the role of these replacements, SA-WT was passaged five times in mouse lungs, and the genome of the mouse-adapted version of the SA-WT strain (SA-M5) was sequenced. SA-M5 lost E358E/K heterogeneity and retained E358, which is the prevalent amino acid at this position among H1N1pdm09 strains. In addition, in the hemagglutinin of SA-M5, two heterogeneous substitutions (G155G/E and S190S/R) were identified. Both viruses, SA-M5 and SA-WT, were compared for their toxicity, ability to replicate, pathogenicity, and immunogenicity in mice. In mice infected with SA-M5 or SA-WT strains, toxicity, virus titer in pulmonary homogenates, and mouse survival did not differ significantly. In contrast, an increase in the immunogenicity of SA-M5 compared to SA-WT was observed. This increase could be due to the substitutions G155G/E and S190S/R in the HA of SA-M5. The prospects for using SA-M5 in studying the immunogenicity mechanisms were also discussed. [ABSTRACT FROM AUTHOR]

Influenza A viruses are RNA viruses that cause epidemics in humans and are enzootic in the pig population globally. In 2009, pig-to-human transmission of a reassortant H1N1 virus (H1N1pdm09) caused the first influenza pandemic of the 21st century. This study investigated the infection dynamics, pathogenesis, and lesions in pigs and ferrets inoculated with natural isolates of swine-adapted, human-adapted, and "pre-pandemic" H1N1pdm09 viruses. Additionally, the direct-contact and aerosol transmission properties of the three H1N1pdm09 isolates were assessed in ferrets. In pigs, inoculated ferrets, and ferrets infected by direct contact with inoculated ferrets, the pre-pandemic H1N1pdm09 virus induced an intermediary viral load, caused the most severe lesions, and had the highest clinical impact. The swine-adapted H1N1pdm09 virus induced the highest viral load, caused intermediary lesions, and had the least clinical impact in pigs. The human-adapted H1N1pdm09 virus induced the highest viral load, caused the mildest lesions, and had the least clinical impact in ferrets infected by direct contact. The discrepancy between viral load and clinical impact presumably reflects the importance of viral host adaptation. Interestingly, the swine-adapted H1N1pdm09 virus was transmitted by aerosols to two-thirds of the ferrets. Further work is needed to assess the risk of human-to-human aerosol transmission of swine-adapted H1N1pdm09 viruses. Author summary: Influenza A viruses (IAVs) have a high evolutionary rate and evolve through genetic drift and reassortment events, elevating their pandemic threat. The last pandemic caused by IAV was a consequence of a spillover of IAV from pigs to humans in 2009 (referred to as H1N1pdm09). The viral and host markers important for host adaptation of IAVs are poorly defined, which makes it difficult to evaluate the pandemic potential of novel swine IAV strains. A method of predicting the risk of human-to-human transmission of IAVs is by using the ferret as an animal model. In this study, we assessed the degree of host adaptation to pigs and ferrets of three different H1N1pdm09 viruses by virological, clinical, and pathological measures. We found that a swine-adapted H1N1pdm09 had the highest viral fitness but the lowest virulence in pigs and that a human-adapted H1N1pdm09 had the highest viral fitness but the lowest virulence in ferrets. In both animal models, we found that an H1N1pdm09 virus resembling a pre-pandemic variant had an intermediary viral fitness but the highest virulence. Our findings indicate that host adaptation is important for the viral fitness and virulence and that an increased viral fitness is not always related with a higher virulence. [ABSTRACT FROM AUTHOR]

In 2009, a novel H1N1 influenza virus caused the first influenza pandemic of the 21st century. Studies have shown that the influenza M gene played important roles in the pathogenicity and transmissibility of the 2009 H1N1 pandemic ((H1N1)pdm09), whilst the underlying mechanism remains unclear. The influenza M gene encodes two proteins, matrix protein 1 and matrix protein 2, which play important roles in viral replication and assembly. In this study, it is found that the M2 protein of the (H1N1)pdm09 virus showed a lower mobility rate than the North America triple-reassortant influenza M2 protein in Polyacrylamide Gel Electrophoresis (PAGE). The site-directed mutations of the amino acids of (H1N1)pdm09 M2 revealed that E79 is responsible for the mobility rate change. Further animal studies showed that the (H1N1)pdm09 containing a single M2-E79K was significantly attenuated compared with the wild-type virus in mice and induced lower proinflammatory cytokines and IFNs in mouse lungs. Further in vitro studies indicated that this mutation also affected NLRP3 inflammasome activation. To reveal the reason why they have different mobility rates, a circular dichroism spectra assay was employed and showed that the two M2 proteins displayed different secondary structures. Overall, our findings suggest that M2 E79 is important for the virus replication and pathogenicity of (H1N1)pdm09 through NLRP3 inflammasome and proinflammatory response. [ABSTRACT FROM AUTHOR]

The Coronavirus Disease 2019 (COVID-19) pandemic and the subsequent increase in respiratory viral infections highlight the need for broad-spectrum antivirals to enable a quick and efficient reaction to current and emerging viral outbreaks. We previously demonstrated that the antihistamine azelastine hydrochloride (azelastine-HCl) exhibited in vitro antiviral activity against SARS-CoV-2. Furthermore, in a phase 2 clinical study, a commercial azelastine-containing nasal spray significantly reduced the viral load in SARS-CoV-2-infected individuals. Here, we evaluate the efficacy of azelastine-HCl against additional human coronaviruses, including the SARS-CoV-2 omicron variant and a seasonal human coronavirus, 229E, through in vitro infection assays, with azelastine showing a comparable potency against both. Furthermore, we determined that azelastine-HCl also inhibits the replication of Respiratory syncytial virus A (RSV A) in both prophylactic and therapeutic settings. In a human 3D nasal tissue model (MucilAirTM-Pool, Epithelix), azelastine-HCl protected tissue integrity and function from the effects of infection with influenza A H1N1 and resulted in a reduced viral load soon after infection. Our results suggest that azelastine-HCl has a broad antiviral effect and can be considered a safe option against the most common respiratory viruses to prevent or treat such infections locally in the form of a nasal spray that is commonly available globally. [ABSTRACT FROM AUTHOR]

• Vaccination acceptability decreased from 91.1% in 2000 to 61.2% in 2010. • Vaccination acceptability increased during the COVID-19 pandemic. • Higher acceptability among persons with higher incomes and education levels. • Widening social and economic gap in terms of vaccine acceptability over time. This study describes the evolution of vaccination acceptability and associated determinants in the French general population between 2000 and 2021, and vaccinations with the highest vaccine hesitancy between 2010 and 2021. Data were collected from the nine national 'Health Barometer' cross-sectional surveys conducted between 2000 and 2021. These surveys included French-speaking individuals aged 18–75 years old who were selected through randomly generated landline and mobile phone numbers. Participants were asked about their acceptability of vaccination in general and their vaccine hesitancy toward any particular vaccinations. Determinants of vaccination acceptability were studied using univariate and multivariate Poisson regressions. The proportion of persons who found vaccination acceptable in general (i.e., answering "very" or "somewhat" favourable in the survey interview) decreased from 91.1% in 2000 to 61.2% in 2010 (the latter year coinciding with the 2009 H1N1 influenza pandemic), increased in 2014 (78.8%), slightly fluctuated until 2019 (74.2%), and increased again in both 2020 (80.0%) and 2021 (82.5%) during the COVID-19 pandemic. Irrespective of the year, acceptability was higher among persons with higher incomes, those with a higher education level, and individuals not living alone. In 2021, for the first time, vaccination acceptability was higher among persons over 44 years old (versus 18–24 year-olds) and among retired persons (versus workers). The highest hesitancy rate for a vaccine was for the 2009 H1N1 influenza virus in 2010 (41% answering "somewhat" or "very" unfavourable). In 2021, the highest rate was for the COVID-19 vaccine (21%). Unlike the experience of the 2009 AH1N1 influenza pandemic, which led to a collapse in vaccination acceptability among the French general population, acceptability continued to increase during the COVID-19 pandemic. However, the pre-2010 level was not reached. Our results show a tendency towards a widening social and economic gap in terms of vaccine acceptability over time. [ABSTRACT FROM AUTHOR]

Background: Before the COVID-19 pandemic, respiratory pathogens such as influenza, parainfluenza, and respiratory syncytial virus were the most commonly detected viruses among hospitalized patients with respiratory tract infections. Methods: This was a retrospective observational study of inpatients and outpatients who attended Jordan University Hospital and underwent Nasopharyngeal Aspiration (NPA) in the periods from December 2017 to December 2018 and from December 2021 to December 2022. The results of multiplex respiratory pathogen real-time PCR tests for nasopharyngeal swab specimens were extracted from the electronic-based molecular diagnostic laboratory record of JUH. We compared the prevalence of the detected viruses as well as the patients' characteristics and outcomes between the two periods. Results: The total number of included patients was 695. Our analysis showed that a higher percentage of patients with hypertension and diabetes presented before the pandemic compared to the same period after it (p-value < 0.001). The need for O2 devices, white blood cell counts, diastolic blood pressure, and the length of hospital stay were significantly higher among patients who presented before the pandemic (p-value < 0.050). Influenza H1N1 (8.70% vs. 4.03%), influenza B (1.67% vs. 0.25%), parainfluenza (1.00% vs. 0.00%), human metapneumovirus (5.35% vs. 0.76%), adenoviruses (6.35% vs. 3.02%), and coronaviruses (8.70% vs. 3.53%) were detected with higher frequency in the period before the pandemic (p-value = 0.011, 0.045, 0.045, 0.000, 0.035, 0.004). These results were similar in terms of changes in the detection rates of viruses after matching the number of tested patients between the periods before and after the pandemic. Conclusions: We have demonstrated a reduction in the detection of several viruses, which might be due to the increase in public awareness toward infection protection measures after the COVID-19 pandemic. [ABSTRACT FROM AUTHOR]

Background: Upper respiratory tract infections (URTIs) are caused by a wide range of viruses and bacteria, however, produce similar symptoms. Routine molecular tests are not performed and empirical use of antibiotics in treating URTIs is a major public health concern. In attempt to unveil the diversity of upper respiratory tract pathogens in the community during COVID-19 pandemic, we have screened 153 nasopharyngeal swab samples from patients having flu like symptoms. Materials and methods: We tested nasopharyngeal swabs by real-time multiplex PCR for 19 viruses and 3 bacteria using cartridge based rapid PCR platform. Results: Of 153 patients sample tested, 103 (67.32%) had a laboratory-confirmed respiratory pathogen. Of the 153 swabs tested rhinovirus/enterovirus was found 25(16.34%), influenza 18(11.77%), RSV 13(8.5%), SARS-CoV2-15(11.11%), other coronaviruses 11(7.19%), parainfluenza 16(10.45%), human metapneumovirus 8(5.23%). Out of 18 influenza cases influenza A was 17(11.12%) and influenza B was 1(0.65%). Among 17 influenza A viruses H1N1pdm09 strain was 9(5.88%), H3 was 5(3.27%). These data shows that even in COVID-19 pandemic period rhinovirus/enterovirus and Influenza dominated over all other respiratory viruses and as a causative agent bacteria might play very insignificant role in URTIs. Conclusion: Our data provides strong evidence against empiric antibiotic use for treating URTIs and highlights a strong need for improving the diagnostic capacity for URTIs by using more molecular testing in the country. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic has been identified as a mental health crisis for children and adolescents in America.1 Social isolation and loneliness during the pandemic present a significant challenge. A rapid systematic review published in this journal found that social isolation correlates with depression and anxiety and may heighten the risk of disorder onset.2 Specifically in an infectious disease context, research on the H1N1 influenza pandemic showed that children in North America required to quarantine were 5 to 30 times more likely to meet criteria for posttraumatic stress disorder than children not under these restrictions.2. [ABSTRACT FROM AUTHOR]

The H1N1 influenza virus is highly infectious and pathogenic, and in recent years, it has often presented seasonal mass outbreaks of infection. People infected with H1N1 will develop a high fever and other respiratory infection symptoms. If not treated in time, complications such as pneumonia may occur. In this study, we focused on developing drugs that can effectively fight against with H1N1 virus. A flavonoid glycoside was extracted from the carambola, then characterized by HR-ESI-MS with the molecular formula C47H58O2, and named carambolaside W. The flavonoid glycosides were found to have good anti-H1N1 influenza virus effects. In this study, we verified that carambolaside W has low toxicity and can effectively inhibit influenza virus replication in vitro. H1N1 virus infection induces intracellular oxidative stress damage to accelerate disease progression. The results showed that carambolaside W effectively inhibited the oxidative stress caused by H1N1 infection. The Western blot assay also revealed that carambolaside W alters the expression of apoptosis-related proteins in vitro and exerts a good anti-H1N1 influenza virus effect. In summary, carambolaside W is a low-toxicity natural flavonoid that can effectively treat the H1N1 influenza virus as a potential anti-H1N1 virus agent. [ABSTRACT FROM AUTHOR]

• Pregnant people are underrepresented in emergency vaccine clinical trials. • Incident pregnancies and related outcomes are underreported in vaccine clinical trials. • Public health emergencies often present disproportionate risk to pregnant people and neonates. • It is both ethical and feasible to enroll pregnant people safely into vaccine trials. • Plans for generating pregnancy-specific data during emergencies are needed. Existing ethics guidance and regulatory requirements emphasize the need for pregnancy-specific safety and efficacy data during the development of vaccines in health emergencies. Our objective was to conduct a systematic review of vaccine clinical trials during active epidemic periods. We searched for Phase II and Phase III vaccine clinical trials initiated during the H1N1 influenza, Middle East Respiratory Syndrome Coronavirus (MERS-CoV), Zika, and Ebola virus disease (EVD) outbreaks from 2009 to 2019. Data were extracted from clinical trial protocols identified in the following registries: ClinicalTrials.gov , Pan African Clinical Trial Registry (PACTR), and all primary registries indicated by the World Health Organization's International Clinical Trials Registry Platform (ICTRP). Published studies from registered clinical trials were located through PubMed. Data was extracted on eligibility criteria and pregnancy outcomes. Data from this study is available in the Center for Open Science Data Repository: https://osf.io/nfk2p/?view%5fonly=47deb3b206724af9b46c9c0c0083a267. We identified 96 vaccine clinical trial protocols and included 84 in analysis. 5 records were excluded in screening for irrelevant abstracts, 7 were excluded in full-text assessment (1 for a therapeutic drug trial, 3 for enrolling elderly adults only, 3 for enrolling children/adolescents only). There were no eligible trials for MERS-CoV or Zika virus vaccines. Overall, 8 protocols explicitly included pregnant people; of these, 3 were completed trials with published results. Incidental pregnancies and outcomes of pregnant participants were reported in 2 studies, 10 studies reported serious adverse events related to pregnancy without mentioning total incidental pregnancies. A total of 411 recorded pregnancy outcomes were reported, with 293 from the 3 pregnancy-eligible studies with results. 71 serious adverse events pertaining to pregnancy were reported from all clinical trials with results. Pregnant people are underrepresented in vaccine clinical trials conducted during outbreaks, resulting in underreporting of pregnancy-related outcomes and a lack of protection for pregnant people and neonates from infectious diseases. [ABSTRACT FROM AUTHOR]

In this article, we consider the role that onset patterns play in shaping how acute global events are taken to be, drawing on illustrative cases from the field of global health emergencies. We identify four temporal manifestation patterns that we argue display distinct political dynamics. First, an emergent onset pattern (e.g. the H1N1 health emergency), with political dynamics dominated by novelty-induced uncertainty and lack of information as well as familiar analogies. Second, an anticipatory onset pattern (e.g. the risk of a global avian flu health emergency), with a political dynamic characterised by dread of an as-of-yet unrealised high-consequence risk. Third, a cyclical onset pattern (e.g. Ebola), with a political dynamic characterised by a sense of familiarity and expectedness, unless eventual 'unexpected' or 'unprecedented' aspects manifest themselves. Lastly, a perpetual onset pattern (e.g. antimicrobial resistance), with political dynamics characterised by incrementalism and low political salience. We argue that acuteness is often associated with a departure from expected manifestation patterns, such as an escalation or other traits that make events appear unfamiliar. Whilst drawing on global health emergences in this paper, the four categories theorised here may also be used on a range of other adversities at the global or local level. [ABSTRACT FROM AUTHOR]

Background: Early studies indicated that vitamin D (VD) exerted pleiotropic extra-skeletal effects in the airway, but the definite linkage between VD deficiency and airway host responses remains unclear. Methods: 142 cases of clinical data from Department of Otolaryngology, the Seventh Affiliated Hospital of Sun Yat-sen University, were collected to characterize the relationship between VD deficiency and chronic rhinosinusitis (CRS). Based on the clinical observations, 2.5-D airway epithelial organoids cultured at the air–liquid interface (ALI) were used to simulate the effects of VD treatment in the development of airway epithelium and the modulation of the host responses against influenza H1N1 virus (representing viral infections) and Staphylococcus aureus (representing bacterial infections) infections in the airway. The intrinsic mechanisms of VD deficiency underlying epithelial remodeling were mapped by transcriptomic as well as proteomic analyses. Results: In this study we observed prevailing VD deficiency among inpatients suffering from CRS, a common disease predominantly characterized by epithelial impairment and remodeling. Relative to control organoids cultured without VD, long-term incubation with VD accelerated basal cell proliferation during nasal epithelial development. Under infectious conditions, VD treatment protected the organoids against influenza H1N1 virus and Staphylococcus aureus invasions by reinforcing the respiratory host defenses, including upregulation of LL37, suppression (or inhibition) of proinflammatory cytokines, strengthening of epithelial integrity, and mucociliary clearance. In silico analysis of transcriptomics and proteomics suggested that VD modulated the epithelial development and remodeling, involving epithelial cell proliferation/differentiation, epithelial–mesenchymal transition (EMT), and cytokine signaling in the immune system, as well as responses to microbe, cell junction organization, and extracellular matrix organization via PTEN signaling, independent of TGF-β signaling. Conclusions: Our findings emphasize the importance of managing VD deficiency in clinical settings for the sake of alleviating pathological epithelial remodeling. Vitamin D promotes epithelial tissue repair and host defense responses against influenza H1N1 and Staphylococcus aureus infections. [ABSTRACT FROM AUTHOR]

Introduction: Pandemic influenza H1N1/09 emerged for the first time in April 2009 and has spread widely across India since then. The number of cases have increased over time with the increasing need for respiratory support, causing significant morbidity and mortality. We evaluated the clinical course and outcomes of patients infected with Influenza A (H1N1) admitted to three multidisciplinary intensive care units (ICU) in Chennai. Materials and methods: We performed a combined retrospective and prospective observational study of all patients admitted with H1N1 pneumonia at three multidisciplinary ICUs in Chennai from October 1, 2018, to January 31, 2019. Data including demographics, risk factors, and clinical courses were recorded. Outcome data including mortality was tracked up to 28 days. Results: A total of 167 patients were admitted during the study period of which 154 were included in this analysis. The mean age of presentation was 58.2 ± 15.6 years and 59.1% of them were males. The mean acute physiology and chronic health evaluation (APACHE) IV and sequential organ failure assessment (SOFA) scores were 62.8 ± 23.2 and 5.8 ± 3.9 respectively. Oxygen delivery devices were required in 25.3% for a mean duration of 26.5 ± 5.7 hours. Non-invasive ventilation or high-flow nasal cannula (HFNC) was needed in 33.1% of patients for 59.9 ± 64.5 hours. The proportion of patients requiring mechanical ventilation was 41.6%. Rescue measures in the form of proning, use of inhaled nitric oxide (iNO), and extracorporeal membrane oxygenation (ECMO) were initiated for refractory hypoxemia in 26.6%, 14.1%, and 6.3% respectively. The mean duration of ventilator support was 8.5 ± 8 days. Tracheostomy was required in 20.3% of patients and 7.8% were ventilator dependent at 28 days. The mean ICU and Hospital length of stay were 8.3 ± 10.3 and 12.2 ± 14.1 days respectively and overall 28-day mortality was 20.1%. Conclusion: A significant proportion of H1N1 patients admitted to the ICU required high-level respiratory support including non-invasive ventilation (NIV), HFNC, or invasive ventilation. Deployment of rescue therapies was common and the overall mortality rate was similar to those reported from Western countries. [ABSTRACT FROM AUTHOR]

Respiratory viruses can be transmitted by multiple modes, including contaminated surfaces, commonly referred to as fomites. Efficient fomite transmission requires that a virus remain infectious on a given surface material over a wide range of environmental conditions, including different relative humidities. Prior work examining the stability of influenza viruses on surfaces has relied upon virus grown in media or eggs, which does not mimic the composition of virus-containing droplets expelled from the human respiratory tract. In this study, we examined the stability of the 2009 pandemic H1N1 (H1N1pdm09) virus on a variety of nonporous surface materials at four different humidities. Importantly, we used virus grown in primary human bronchial epithelial cell (HBE) cultures from different donors to recapitulate the physiological microenvironment of expelled viruses. We observed rapid inactivation of H1N1pdm09 on copper under all experimental conditions. In contrast to copper, viruses were stable on polystyrene plastic, stainless steel, aluminum, and glass, at multiple relative humidities, but greater decay on acrylonitrile butadiene styrene (ABS) plastic was observed at short time points. However, the half-lives of viruses at 23% relative humidity were similar among noncopper surfaces and ranged from 4.5 to 5.9 h. Assessment of H1N1pdm09 longevity on nonporous surfaces revealed that virus persistence was governed more by differences among HBE culture donors than by surface material. Our findings highlight the potential role of an individual's respiratory fluid on viral persistence and could help explain heterogeneity in transmission dynamics. [ABSTRACT FROM AUTHOR]

This study investigated the antiviral activity of aqueous leaf extract of Costus speciosus (TB100) against influenza A. Pretreatment of TB100 in RAW264.7 cells enhanced antiviral activity in an assay using the green fluorescence-expressing influenza A/Puerto Rico/8/1934 (H1N1) virus. The fifty percent effective concentration (EC50) and fifty percent cytotoxic concentration (CC50) were determined to be 15.19 ± 0.61 and 117.12 ± 18.31 µg/mL, respectively, for RAW264.7 cells. Based on fluorescent microscopy, green fluorescence protein (GFP) expression and viral copy number reduction confirmed that TB100 inhibited viral replication in murine RAW264.7 and human A549 and HEp2 cells. In vitro pretreatment with TB100 induced the phosphorylation of transcriptional activators TBK1, IRF3, STAT1, IKB-α, and p65 associated with interferon pathways, indicating the activation of antiviral defenses. The safety and protective efficacy of TB100 were assessed in BALB/c mice as an oral treatment and the results confirmed that it was safe and effective against influenza A/Puerto Rico/8/1934 (H1N1), A/Philippines/2/2008 (H3N2), and A/Chicken/Korea/116/2004 (H9N2). High-performance liquid chromatography of aqueous extracts led to the identification of cinnamic, caffeic, and chlorogenic acids as potential chemicals for antiviral responses. Further confirmatory studies using these acids revealed that each of them confers significant antiviral effects against influenza when used as pretreatment and enhances the antiviral response in a time-dependent manner. These findings suggest that TB100 has the potential to be developed into an antiviral agent that is effective against seasonal influenza. [ABSTRACT FROM AUTHOR]

In the context of continued spread of coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 and the emergence of new variants, the demand for rapid, accurate, and frequent detection is increasing. Moreover, the new predominant strain, Omicron variant, manifests more similar clinical features to those of other common respiratory infections. The concurrent detection of multiple potential pathogens helps distinguish SARS-CoV-2 infection from other diseases with overlapping symptoms, which is significant for providing tailored treatment to patients and containing the outbreak. Here, we report a lab-on-a-chip biosensing platform for SARS-CoV-2 detection based on the subwavelength grating micro-ring resonator. The sensing surface is functionalized by specific antibody against SARS-CoV-2 spike protein, which could produce redshifts of resonant peaks by antigen–antibody combination, thus achieving quantitative detection. Additionally, the sensor chip is integrated with a microfluidic chip featuring an anti-backflow Y-shaped structure that enables the concurrent detection of two analytes. In this study, we realized the detection and differentiation of COVID-19 and influenza A H1N1. Experimental results indicate that the limit of detection of our device reaches 100 fg/ml (1.31 fM) within 15 min detecting time, and cross-reactivity tests manifest the specificity of the optical diagnostic assay. Furthermore, the integrated packaging and streamlined workflow facilitate its use for clinical applications. Thus, the biosensing platform presents a promising approach for attaining highly sensitive, selective, multiplexed, and quantitative point-of-care diagnosis and distinction between COVID-19 and influenza. [ABSTRACT FROM AUTHOR]

Influenza virus (IV) causes several outbreaks of the flu each year resulting in an economic burden to the healthcare system in the billions of dollars. Several influenza pandemics have occurred during the last century and estimated to have caused 100 million deaths. There are four genera of IV, A (IVA), B (IVB), C (IVC), and D (IVD), with IVA being the most virulent to the human population. Hemagglutinin (HA) is an IVA surface protein that allows the virus to attach to host cell receptors and enter the cell. Here we have characterised the high-resolution structures of seven IVA HAs, with one in complex with the anti-influenza head-binding antibody C05. Our analysis revealed conserved receptor binding residues in all structures, as seen in previously characterised IV HAs. Amino acid conservation is more prevalent on the stalk than the receptor binding domain (RBD; also called the head domain), allowing the virus to escape from antibodies targeting the RBD. The equivalent site of C05 antibody binding to A/Denver/57 HA appears hypervariable in the other H1N1 IV HAs. Modifications within this region appear to disrupt binding of the C05 antibody, as these HAs no longer bind the C05 antibody by analytical SEC. Our study brings new insights into the structural and functional recognition of IV HA proteins and can contribute to further development of anti-influenza vaccines. [ABSTRACT FROM AUTHOR]

The development of environment‐friendly, step economic couplings to generate structurally diverse macrocyclic compounds is highly desirable but poses a marked challenge. Inspired by the C−H oxidation mechanism of cytochromes P450, an unprecedented and practical RhIII‐catalyzed acylmethylation macrocyclization via C−H/O2 dual activation has been developed by us. The process of macrocyclization is facilitated by a synergic coordination from pyridine and ester group. Interestingly, the reaction mode derives from a three‐component coupling which differs from established olefination and alkylation paths. Density functional theory (DFT) calculations and control experiments revealed the mechanism of this unique C−H/O2 dual activation. The newly achieved acylmethylation macrocyclic products and their derivatives showed a potent anti‐H1N1 bioactivity, which may provide an opportunity for the discovery of novel anti‐H1N1 macrocyclic leading compounds. [ABSTRACT FROM AUTHOR]

The development of environment‐friendly, step economic couplings to generate structurally diverse macrocyclic compounds is highly desirable but poses a marked challenge. Inspired by the C−H oxidation mechanism of cytochromes P450, an unprecedented and practical RhIII‐catalyzed acylmethylation macrocyclization via C−H/O2 dual activation has been developed by us. The process of macrocyclization is facilitated by a synergic coordination from pyridine and ester group. Interestingly, the reaction mode derives from a three‐component coupling which differs from established olefination and alkylation paths. Density functional theory (DFT) calculations and control experiments revealed the mechanism of this unique C−H/O2 dual activation. The newly achieved acylmethylation macrocyclic products and their derivatives showed a potent anti‐H1N1 bioactivity, which may provide an opportunity for the discovery of novel anti‐H1N1 macrocyclic leading compounds. [ABSTRACT FROM AUTHOR]

Policy PointsThe critical task of preparedness is inseparable from the regular work of advancing population health and health equity. [ABSTRACT FROM AUTHOR]

SARS-CoV-2 continues to circulate in the human population necessitating regular booster immunization for its long-term control. Ideally, vaccines should ideally not only protect against symptomatic disease, but also prevent transmission via asymptomatic shedding and cover existing and future variants of the virus. This may ultimately only be possible through induction of potent and long-lasting immune responses in the nasopharyngeal tract, the initial entry site of SARS-CoV-2. To this end, we have designed a vaccine based on recombinantly expressed receptor binding domain (RBD) of SARS-CoV-2, fused to the C-terminus of C. perfringens enterotoxin, which is known to target Claudin-4, a matrix molecule highly expressed on mucosal microfold (M) cells of the nasal and bronchial-associated lymphoid tissues. To further enhance immune responses, the vaccine was adjuvanted with a novel toll-like receptor 3/RIG-I agonist (Riboxxim™), consisting of synthetic short double stranded RNA. Intranasal prime-boost immunization of mice induced robust mucosal and systemic anti-SARS-CoV-2 neutralizing antibody responses against SARS-CoV-2 strains Wuhan-Hu-1, and several variants (B.1.351/beta, B.1.1.7/alpha, B.1.617.2/delta), as well as systemic T-cell responses. A combination vaccine with M-cell targeted recombinant HA1 from an H1N1 G4 influenza strain also induced mucosal and systemic antibodies against influenza. Taken together, the data show that development of an intranasal SARS-CoV-2 vaccine based on recombinant RBD adjuvanted with a TLR3 agonist is feasible, also as a combination vaccine against influenza. [ABSTRACT FROM AUTHOR]

Current influenza vaccines target highly variable surface glycoproteins; thus, mismatches between vaccine strains and circulating strains often diminish vaccine protection. For this reason, there is still a critical need to develop effective influenza vaccines able to protect also against the drift and shift of different variants of influenza viruses. It has been demonstrated that influenza nucleoprotein (NP) is a strong candidate for a universal vaccine, which contributes to providing cross-protection in animal models. In this study, we developed an adjuvanted mucosal vaccine using the recombinant NP (rNP) and the TLR2/6 agonist S-[2,3-bispalmitoyiloxy-(2R)-propyl]-R-cysteinyl-amido-monomethoxyl-poly-ethylene-glycol (BPPcysMPEG). The vaccine efficacy was compared with that observed following parenteral vaccination of mice with the same formulation. Mice vaccinated with 2 doses of rNP alone or co-administered with BPPcysMPEG by the intranasal (i.n.) route showed enhanced antigen-specific humoral and cellular responses. Moreover, NP-specific humoral immune responses, characterized by significant NP-specific IgG and IgG subclass titers in sera and NP-specific IgA titers in mucosal territories, were remarkably increased in mice vaccinated with the adjuvanted formulation as compared with those of the non-adjuvanted vaccination group. The addition of BPPcysMPEG also improved NP-specific cellular responses in vaccinated mice, characterized by robust lymphoproliferation and mixed Th1/Th2/Th17 immune profiles. Finally, it is notable that the immune responses elicited by the novel formulation administered by the i.n. route were able to confer protection against the influenza H1N1 A/Puerto Rico/8/1934 virus. [ABSTRACT FROM AUTHOR]

• Acute and past helminth infection suppress antibody responses to influenza vaccination. • Vaccine-induced protection against an influenza challenge infection is abrogated in helminth-infected mice. • Suppressed vaccination efficacy is associated with a systemic and sustained expansion of Tr1 cells. • Implementation of adjuvanted or prime-boost vaccination does not restore vaccination efficacy. • Drug induced deworming does not restore vaccination efficacy. Helminth parasites infect more than a quarter of the human population and inflict significant changes to the immunological status of their hosts. Several human studies report impaired responses to vaccinations in helminth-infected individuals. Analysing the impact of helminth infections on the efficacy of influenza vaccinations in the mouse system helps to elucidate the underlying immunological processes. Concurrent infection with the parasitic nematode Litomosoides sigmodontis reduced the quantity and quality of antibody responses to vaccination against seasonal influenza in BALB/c and C57BL/6 mice. This led to impaired vaccination-induced protection against challenge infections with the human pathogenic 2009 pandemic H1N1 influenza A virus in helminth-infected mice. Impaired responses were also observed if vaccinations were performed after immune-driven or drug-induced clearance of a previous helminth infection. Mechanistically, the suppression was associated with a systemic and sustained expansion of IL-10-producing CD4+CD49b+LAG-3+ type 1 regulatory T cells and partially abrogated by in vivo blockade of the IL-10 receptor. In summary, these findings raise the concern that individuals in helminth-endemic areas may not always benefit from vaccinations, even in the absence of an acute and diagnosable helminth infection. [ABSTRACT FROM AUTHOR]

The segmented RNA genome of influenza A viruses (IAVs) enables viral evolution through genetic reassortment after multiple IAVs coinfect the same cell, leading to viruses harboring combinations of eight genomic segments from distinct parental viruses. Existing data indicate that reassortant genotypes are not equiprobable; however, the low throughput of available virology techniques does not allow quantitative analysis. Here, we have developed a high-throughput single-cell droplet microfluidic system allowing encapsulation of IAV-infected cells, each cell being infected by a single progeny virion resulting from a coinfection process. Customized barcoded primers for targeted viral RNA sequencing enabled the analysis of 18,422 viral genotypes resulting from coinfection with two circulating human H1N1pdm09 and H3N2 IAVs. Results were highly reproducible, confirmed that genetic reassortment is far from random, and allowed accurate quantification of reassortants including rare events. In total, 159 out of the 254 possible reassortant genotypes were observed but with widely varied prevalence (from 0.038 to 8.45%). In cells where eight segments were detected, all 112 possible pairwise combinations of segments were observed. The inclusion of data from single cells where less than eight segments were detected allowed analysis of pairwise cosegregation between segments with very high confidence. Direct coupling analysis accurately predicted the fraction of pairwise segments and full genotypes. Overall, our results indicate that a large proportion of reassortant genotypes can emerge upon coinfection and be detected over a wide range of frequencies, highlighting the power of our tool for systematic and exhaustive monitoring of the reassortment potential of IAVs. [ABSTRACT FROM AUTHOR]

Influenza viruses cause a severe threat to global health, which can lead to annual epidemics and cause pandemics occasionally. However, the number of anti‐influenza therapeutic agents is very limited. Polysaccharides, extracted from Picochlorum sp. (PPE), seaweed Polysaccharides, have exhibited antiviral activity and were expected to be used for influenza treatment. In our research, the capability of PPE to inhibit H1N1 infection was proved in MDCK cells. PPE could make MDCK cells avoid being infected with H1N1 and inhibited nuclear fragmentation and condensation of chromatin. PPE evidently inhibited the generation of reactive oxygen species in MDCK cells. Mechanism study revealed that PPE prevented MDCK cells from H1N1 infection through induction of apoptosis by stimulating AKT signaling pathway and suppressing p‐p53 signaling pathway. In conclusion, PPE turns out to act as a prospective antiviral drug for H1N1 influenza. [ABSTRACT FROM AUTHOR]

In this contribution, we investigate the effects of the immunological memory in the population against the strain mutation of a disease, assuming that this memory is enhanced by the dynamics that follow a multi-order fractional SIRC model. We use weekly infection data on Influenza H1N1 in the state of Rio Grande do Sul, reported in the year of 2010, as the guide for our simulations and parameter choices. The simulated results suggest that the best scenarios, regarding the Influenza H1N1 data fit and that have a long-term prevention of reinfection for mutated strains of a circulating disease is the one in which the compartment of the population has a distinct level of immunological memory. Hence, any immunization strategy should be applied as early as possible, allowing the individual to acquire immunological memory before the strain can undergo mutations. [ABSTRACT FROM AUTHOR]

The influenza neuraminidase (NA) is a promising target for next-generation vaccines. Protection induced by vaccination with the computationally optimized broadly reactive NA antigen (N1-I COBRA NA) was characterized in both influenza serologically naive and pre-immune ferret models following H1N1 (A/California/07/2009, CA/09) or H5N1 (A/Vietnam/1203/2004, Viet/04) influenza challenges. The N1-I COBRA NA vaccine elicited antibodies with neutralizing ELLA activity against both seasonal and pandemic H1N1 influenza, as well as the H5N1 influenza virus. In both models, N1-I COBRA NA-vaccinated ferrets that were challenged with CA/09 virus had similar morbidity (weight loss and clinical symptoms) as ferrets vaccinated with the CA/09 HA control vaccine. There were significantly reduced viral titers compared to the mock-vaccinated control animals. Ferrets vaccinated with N1-I COBRA NA or Viet/04 NA vaccines were protected against the H5N1 virus infection with minimal clinical symptoms and negligible weight loss. In contrast, ferrets vaccinated with the CA/09 NA vaccine lost ~10% of their original body weight with 25% mortality. Vaccination with either HA or NA vaccines did not inhibit contact transmission of CA/09 virus to naïve cage mates. Overall, the N1-I COBRA vaccine elicited protective immune responses against both H1N1 and H5N1 infections and partially mitigated disease in contact-transmission receiving ferrets. These results indicate that the N1-I COBRA NA performed similarly to the CA/09 HA and NA positive controls. Therefore, the N1-I COBRA NA alone induces protection against viruses from both H5N1 and H1N1 subtypes, indicating its value as a vaccine component in broadly protective influenza vaccines. [ABSTRACT FROM AUTHOR]