Influenza virus, an RNA virus of the Orthomyxoviridae family, is responsible for widespread seasonal epidemics that result in 3 to 5 million severe illnesses and more than half a million deaths annually. Given the persistent circulation of pandemic influenza variants and increasing resistance to available inhibitors, there is an urgent need for new antiviral drugs effective against various viral subtypes. Viral RNA-dependent RNA polymerase, essential for viral replication, has emerged as a promising drug target. The PA subunit with endonuclease function is especially interesting, as development of the highly potent baloxavir marboxil (Xofluza) validated its importance as a novel drug target. Flavonoids have long been studied for their anti-influenza activity but have only recently been recognized as endonuclease inhibitors. We previously identified luteolin and its glucoside derivate, orientin, as potent endonuclease inhibitors, with their binding illustrated by X-ray crystallography structures. Building on this, we employed a scaffold-hopping approach based on the luteolin structure to design structurally distinct compounds that resemble the flavonoid scaffold. Using an AlphaScreen binding assay, we identified 33 as a submicromolar PA inhibitor with low toxicity. We solved the crystal structure of the PA endonuclease-binding pseudoflavonoid 36, which has similar structure and inhibitory potency to 33. Furthermore, we identified 24, 33, 34 and 36 as inhibitors of influenza polymerase in a minireplicon luciferase reporter assay as well as inhibitors of live H1N1 virus infection in A549 human lung cells.

• Publication type
• Journal Article MeSH

BACKGROUND: Influenza is a relatively serious infection that causes considerable morbidity and mortality. Epidemics of influenza are reported almost every year. METHODS: Based on the Czech national all-cause mortality and acute respiratory infection/influenza-like illness surveillance data for the 1999/2000 to 2019/2020 influenza seasons, excess deaths attributable to influenza were estimated using the threshold derived as 90th percentile of death counts during nonepidemic periods. Daily death counts broken by the 5-year age intervals were modelled via Poisson generalised additive model. RESULTS: The estimated total number of excess deaths from influenza during study period was 22,306. Thus, the mean total of excess deaths related to influenza per season was 1062 for the age group 40-94 years. The total number of excess deaths increased steadily with age from the 40-44 age group to the 85-89 age group, which accounted for the highest percentage of excess deaths (17%), followed closely by the 80-84 age group (16%). The age groups 40-44 years and 45-49 years contributed the least (3% each). More than three quarters of excess deaths occurred at age 65 and over (17,027 cases; 76%). Relative numbers of excess deaths per 100,000 population peaked in the oldest age groups of 85-89 and 90-94 years. CONCLUSIONS: We estimate that at least 0.98% of all-cause mortality throughout the study period was attributable to influenza in the Czech Republic. This excess is not negligible, and public health actions in the field of influenza prevention are vitally needed.

• Keywords
• excess mortality, influenza, morbidity, mortality,
• MeSH
• Influenza, Human * mortality   epidemiology   MeSH
• Child MeSH
• Adult MeSH
• Infant MeSH
• Middle Aged MeSH
• Humans MeSH
• Adolescent MeSH
• Young Adult MeSH
• Infant, Newborn MeSH
• Child, Preschool MeSH
• Seasons MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Check Tag
• Child MeSH
• Adult MeSH
• Infant MeSH
• Middle Aged MeSH
• Humans MeSH
• Adolescent MeSH
• Young Adult MeSH
• Male MeSH
• Infant, Newborn MeSH
• Child, Preschool MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Czech Republic epidemiology   MeSH

BACKGROUND: The Global Influenza Hospital Surveillance Network (GIHSN) has since 2012 provided patient-level data on severe influenza-like-illnesses from >100 participating clinical sites worldwide based on a core protocol and consistent case definitions. METHODS: We used multivariable logistic regression to assess the risk of intensive care unit admission, mechanical ventilation, and in-hospital death among hospitalized patients with influenza and explored the role of patient-level covariates and country income level. RESULTS: The data set included 73 121 patients hospitalized with respiratory illness in 22 countries, including 15 660 with laboratory-confirmed influenza. After adjusting for patient-level covariates we found a 7-fold increase in the risk of influenza-related intensive care unit admission in lower middle-income countries (LMICs), compared with high-income countries (P = .01). The risk of mechanical ventilation and in-hospital death also increased by 4-fold in LMICs, though these differences were not statistically significant. We also find that influenza mortality increased significantly with older age and number of comorbid conditions. Across all severity outcomes studied and after controlling for patient characteristics, infection with influenza A/H1N1pdm09 was more severe than with A/H3N2. CONCLUSIONS: Our study provides new information on influenza severity in underresourced populations, particularly those in LMICs.

• Keywords
• disease severity, global health, influenza epidemiology, lower middle-income countries, surveillance,
• MeSH
• Influenza, Human * epidemiology   MeSH
• Hospitalization MeSH
• Humans MeSH
• Hospital Mortality MeSH
• Hospitals MeSH
• Influenza A Virus, H3N2 Subtype MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

In the shadow of SARS-CoV-2, influenza seems to be an innocent virus, although new zoonotic influenza viruses evolved by mutations may lead to severe pandemics. According to WHO, there is an urgent need for better antiviral drugs. Blocking viral hemagglutinin with multivalent N-acetylneuraminic acid derivatives is a promising approach to prevent influenza infection. Moreover, dual inhibition of both hemagglutinin and neuraminidase may result in a more powerful effect. Since both viral glycoproteins can bind to neuraminic acid, we have prepared three series of amphiphilic self-assembling 2-thio-neuraminic acid derivatives constituting aggregates in aqueous medium to take advantage of their multivalent effect. One of the series was prepared by the azide-alkyne click reaction, and the other two by the thio-click reaction to yield neuraminic acid derivatives containing lipophilic tails of different sizes and an enzymatically stable thioglycosidic bond. Two of the three bis-octyl derivatives produced proved to be active against influenza viruses, while all three octyl derivatives bound to hemagglutinin and neuraminidase from H1N1 and H3N2 influenza types.

• Keywords
• aggregates, hemagglutinin, influenza, neuraminidase, sialic acid,
• MeSH
• Influenza, Human * drug therapy   MeSH
• Hemagglutinin Glycoproteins, Influenza Virus metabolism   MeSH
• Hemagglutinins pharmacology   MeSH
• N-Acetylneuraminic Acid pharmacology   metabolism   MeSH
• Neuraminic Acids MeSH
• Humans MeSH
• Neuraminidase metabolism   MeSH
• Influenza A Virus, H1N1 Subtype * MeSH
• Influenza A Virus, H3N2 Subtype MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Hemagglutinin Glycoproteins, Influenza Virus MeSH
• Hemagglutinins MeSH
• N-Acetylneuraminic Acid MeSH
• Neuraminic Acids MeSH
• Neuraminidase MeSH

The part of the influenza polymerase PA subunit featuring endonuclease activity is a target for anti-influenza therapies, including the FDA-approved drug Xofluza. A general feature of endonuclease inhibitors is their ability to chelate Mg2+ or Mn2+ ions located in the enzyme's catalytic site. Previously, we screened a panel of flavonoids for PA inhibition and found luteolin and its C-glucoside orientin to be potent inhibitors. Through structural analysis, we identified the presence of a 3',4'-dihydroxyphenyl moiety as a crucial feature for sub-micromolar inhibitory activity. Here, we report results from a subsequent investigation exploring structural changes at the C-7 and C-8 positions of luteolin. Experimental IC50 values were determined by AlphaScreen technology. The most potent inhibitors were C-8 derivatives with inhibitory potencies comparable to that of luteolin. Bio-isosteric replacement of the C-7 hydroxyl moiety of luteolin led to a series of compounds with one-order-of-magnitude-lower inhibitory potencies. Using X-ray crystallography, we solved structures of the wild-type PA-N-terminal domain and its I38T mutant in complex with orientin at 1.9 Å and 2.2 Å resolution, respectively.

• Keywords
• Mannich reaction, RNA polymerase, bio-isosterism, cross-coupling, endonuclease inhibitor, flavonoids, influenza,
• MeSH
• Antiviral Agents chemical synthesis   pharmacology   MeSH
• Endonucleases antagonists & inhibitors   MeSH
• Catalytic Domain drug effects   MeSH
• Luteolin chemical synthesis   pharmacology   MeSH
• Orthomyxoviridae drug effects   MeSH
• Viral Proteins antagonists & inhibitors   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Antiviral Agents MeSH
• Endonucleases MeSH
• Luteolin MeSH
• Viral Proteins MeSH

Vaccination is one of the most successful medical interventions that has saved the life of millions of people. Vaccination is particularly important in patients with multiple myeloma, who have an increased risk of infections due to the disease-inherent immune suppression, and because of the immune suppressive effects of therapy. Hence, all appropriate measures should be exploited, to elicit an effective immune response to common pathogens like influenza, pneumococci, varicella zoster virus, and to those bacteria and viruses (haemophilus influenzae, meningococci, and hepatitis) that frequently may pose a significant risk to patients with multiple myeloma. Patients after autologous, and specifically after allogeneic transplantation have severely reduced antibody titers, and therefore require a broader spectrum of vaccinations. Response to vaccination in myeloma often is less vigorous than in the general population, mandating either measurement of the postvaccination antibody titers and/or repeating the vaccination. Here, we compile the existing data on vaccination in multiple myeloma and provide recommendations for clinical practice.

• MeSH
• Immunosuppressive Agents administration & dosage   adverse effects   therapeutic use   MeSH
• Communicable Diseases etiology   MeSH
• Clinical Trials as Topic MeSH
• Consensus MeSH
• Communicable Disease Control * MeSH
• Humans MeSH
• Multiple Myeloma complications   immunology   therapy   MeSH
• Practice Guidelines as Topic * MeSH
• Vaccination * MeSH
• Vaccines administration & dosage   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Meta-Analysis MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Geographicals
• Europe MeSH
• Names of Substances
• Immunosuppressive Agents MeSH
• Vaccines MeSH

BACKGROUND: Since 2011, the Global Influenza Hospital Surveillance Network (GIHSN) has used active surveillance to prospectively collect epidemiological and virological data on patients hospitalized with influenza virus infection. Here, we describe influenza virus strain circulation in the GIHSN participant countries during 2017-2018 season and examine factors associated with complicated hospitalization among patients admitted with laboratory-confirmed influenza illness. METHODS: The study enrolled patients who were hospitalized in a GIHSN hospital in the previous 48 h with acute respiratory symptoms and who had symptoms consistent with influenza within the 7 days before admission. Enrolled patients were tested by reverse transcription-polymerase chain reaction to confirm influenza virus infection. "Complicated hospitalization" was defined as a need for mechanical ventilation, admission to an intensive care unit, or in-hospital death. In each of four age strata (< 15, 15-< 50, 50-< 65, and ≥ 65 years), factors associated with complicated hospitalization in influenza-positive patients were identified by mixed effects logistic regression and those associated with length of hospital stay using a linear mixed-effects regression model. RESULTS: The study included 12,803 hospitalized patients at 14 coordinating sites in 13 countries, of which 4306 (34%) tested positive for influenza. Influenza viruses B/Yamagata, A/H3N2, and A/H1N1pdm09 strains dominated and cocirculated, although the dominant strains varied between sites. Complicated hospitalization occurred in 10.6% of influenza-positive patients. Factors associated with complicated hospitalization in influenza-positive patients included chronic obstructive pulmonary disease (15-< 50 years and ≥ 65 years), diabetes (15-< 50 years), male sex (50-< 65 years), hospitalization during the last 12 months (50-< 65 years), and current smoking (≥65 years). Chronic obstructive pulmonary disease (50-< 65 years), other chronic conditions (15-< 50 years), influenza A (50-< 65 years), and hospitalization during the last 12 months (< 15 years) were associated with a longer hospital stay. The proportion of patients with complicated influenza did not differ between influenza A and B. CONCLUSIONS: Complicated hospitalizations occurred in over 10% of patients hospitalized with influenza virus infection. Factors commonly associated with complicated or longer hospitalization differed by age group but commonly included chronic obstructive pulmonary disease, diabetes, and hospitalization during the last 12 months.

• Keywords
• Epidemiology, Hospitalization, Influenza, Mortality, Risk factors,
• MeSH
• Betainfluenzavirus genetics   MeSH
• Influenza, Human epidemiology   mortality   virology   MeSH
• Length of Stay MeSH
• Child MeSH
• Adult MeSH
• Hospitalization * MeSH
• Intensive Care Units MeSH
• Infant MeSH
• Middle Aged MeSH
• Humans MeSH
• Adolescent MeSH
• Young Adult MeSH
• Hospital Mortality MeSH
• Reverse Transcriptase Polymerase Chain Reaction MeSH
• Child, Preschool MeSH
• Prospective Studies MeSH
• Risk Factors MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Respiration, Artificial MeSH
• Influenza A Virus, H1N1 Subtype genetics   MeSH
• Influenza A Virus, H3N2 Subtype genetics   MeSH
• Check Tag
• Child MeSH
• Adult MeSH
• Infant MeSH
• Middle Aged MeSH
• Humans MeSH
• Adolescent MeSH
• Young Adult MeSH
• Male MeSH
• Child, Preschool MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH

BACKGROUND: Morbidity, severity, and mortality associated with annual influenza epidemics are of public health concern. We analyzed surveillance data on hospitalized laboratory-confirmed influenza cases admitted to intensive care units to identify common determinants for fatal outcome and inform and target public health prevention strategies, including risk communication. METHODS: We performed a descriptive analysis and used Poisson regression models with robust variance to estimate the association of age, sex, virus (sub)type, and underlying medical condition with fatal outcome using European Union data from 2009 to 2017. RESULTS: Of 13 368 cases included in the basic dataset, 2806 (21%) were fatal. Age ≥40 years and infection with influenza A virus were associated with fatal outcome. Of 5886 cases with known underlying medical conditions and virus A subtype included in a more detailed analysis, 1349 (23%) were fatal. Influenza virus A(H1N1)pdm09 or A(H3N2) infection, age ≥60 years, cancer, human immunodeficiency virus infection and/or other immune deficiency, and heart, kidney, and liver disease were associated with fatal outcome; the risk of death was lower for patients with chronic lung disease and for pregnant women. CONCLUSIONS: This study re-emphasises the importance of preventing influenza in the elderly and tailoring strategies to risk groups with underlying medical conditions.

• Keywords
• EU, age, influenza virus, intensive care units, underlying medical conditions,
• Publication type
• Journal Article MeSH

Severe influenza infection has no effective treatment available. One of the key barriers to developing host-directed therapy is a lack of reliable prognostic factors needed to guide such therapy. Here, we use a network analysis approach to identify host factors associated with severe influenza and fatal outcome. In influenza patients with moderate-to-severe diseases, we uncover a complex landscape of immunological pathways, with the main changes occurring in pathways related to circulating neutrophils. Patients with severe disease display excessive neutrophil extracellular traps formation, neutrophil-inflammation and delayed apoptosis, all of which have been associated with fatal outcome in animal models. Excessive neutrophil activation correlates with worsening oxygenation impairment and predicted fatal outcome (AUROC 0.817-0.898). These findings provide new evidence that neutrophil-dominated host response is associated with poor outcomes. Measuring neutrophil-related changes may improve risk stratification and patient selection, a critical first step in developing host-directed immune therapy.

• MeSH
• Neutrophil Activation immunology   MeSH
• Cell Cycle immunology   MeSH
• Influenza, Human immunology   mortality   pathology   MeSH
• Gene Expression genetics   MeSH
• Extracellular Traps immunology   MeSH
• Middle Aged MeSH
• Humans MeSH
• Neutrophils immunology   MeSH
• Lung immunology   MeSH
• Prospective Studies MeSH
• Respiratory Insufficiency mortality   pathology   virology   MeSH
• Respiration, Artificial MeSH
• Influenza A Virus, H1N1 Subtype immunology   isolation & purification   MeSH
• Influenza A Virus, H3N2 Subtype immunology   isolation & purification   MeSH
• Influenza B virus immunology   isolation & purification   MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Influenza neuraminidase is responsible for the escape of new viral particles from the infected cell surface. Several neuraminidase inhibitors are used clinically to treat patients or stockpiled for emergencies. However, the increasing development of viral resistance against approved inhibitors has underscored the need for the development of new antivirals effective against resistant influenza strains. A facile, sensitive, and inexpensive screening method would help achieve this goal. Recently, we described a multiwell plate-based DNA-linked inhibitor antibody assay (DIANA). This highly sensitive method can quantify femtomolar concentrations of enzymes. DIANA also has been applied to high-throughput enzyme inhibitor screening, allowing the evaluation of inhibition constants from a single inhibitor concentration. Here, we report the design, synthesis, and structural characterization of a tamiphosphor derivative linked to a reporter DNA oligonucleotide for the development of a DIANA-type assay to screen potential influenza neuraminidase inhibitors. The neuraminidase is first captured by an immobilized antibody, and the test compound competes for binding to the enzyme with the oligo-linked detection probe, which is then quantified by qPCR. We validated this novel assay by comparing it with the standard fluorometric assay and demonstrated its usefulness for sensitive neuraminidase detection as well as high-throughput screening of potential new neuraminidase inhibitors.

• Keywords
• DIANA, assay, crystallography, influenza neuraminidase,
• MeSH
• Antiviral Agents chemistry   pharmacology   MeSH
• Influenza, Human drug therapy   enzymology   virology   MeSH
• DNA chemistry   MeSH
• Enzyme Inhibitors chemistry   pharmacology   MeSH
• Phosphorous Acids chemistry   MeSH
• Humans MeSH
• Neuraminidase antagonists & inhibitors   metabolism   MeSH
• Oseltamivir analogs & derivatives   chemistry   MeSH
• Drug Evaluation, Preclinical methods   MeSH
• Reproducibility of Results MeSH
• Viral Proteins antagonists & inhibitors   metabolism   MeSH
• Influenza A virus drug effects   enzymology   physiology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Antiviral Agents MeSH
• DNA MeSH
• Enzyme Inhibitors MeSH
• Phosphorous Acids MeSH
• Neuraminidase MeSH
• Oseltamivir MeSH
• tamiphosphor MeSH Browser
• Viral Proteins MeSH