Skip to main content

Posts

Showing posts with the label zanamivir

#Zanamivir - #Amantadine Conjugate: A Dual-Action Agent with Broad-Spectrum Synergistic #Antiviral Efficacy

  Abstract Influenza A virus is a highly contagious respiratory pathogen, and its rapid and continuous adaptive mutations for immune escape have limited the efficacy of existing vaccines and antiviral drugs. Here, we report a multimechanism anti-influenza platform based on the conjugation of zanamivir (ZMV) with amantadine (Aman). Aman acts as a hydrophobic tag that promotes the degradation of neuraminidase and concurrently enhances the physicochemical properties of ZMV , leading to improved membrane permeability and a significantly prolonged half-life. Meanwhile, the ZMV moiety counteracts Aman-induced cytotoxic autophagy . The resulting conjugate, compound 7j , exhibits potent activity against a wide range of neuraminidase and M2 ion channel mutations . Notably, a single intravenous dose of 7j fully protected mice from a lethal H1N1 challenge . Our work demonstrates that the rational fusion of ZMV and Aman achieves synergistic multimechanistic antiviral activity with enhanced eff...

#Report on #influenza viruses received and tested by the #Melbourne #WHO CC for #Reference and Research on #Influenza during 2024

  Abstract As part of its role in the World Health Organization (WHO) Global Influenza Surveillance and Response System (GISRS), the WHO Collaborating Centre for Reference and Research on Influenza in Melbourne received 12,180 human influenza-positive samples during 2024 . Viruses were analysed for their antigenic, genetic, and antiviral susceptibility properties . Selected viruses were propagated in qualified cells or embryonated hens’ eggs for potential use in seasonal influenza virus vaccines. During 2024 , influenza A( H1N1 )pdm09 and A( H3N2 ) viruses predominated , accounting for 33% and 42%, respectively, of all viruses received, compared to 5% for influenza B/Victoria . Of note, one influenza A(H5N1) virus was also received in 2024 . The majority of A(H1N1)pdm09 (98%), A(H3N2) (88%) and influenza B (100%) viruses analysed at the Centre were found to be antigenically and genetically similar to the respective WHO recommended vaccine strains for the Southern Hemisphere in 2024...

Genomic #Evolution of #Influenza A Virus During the 2024-2025 Season, the Johns Hopkins Health System: Antigenic Drift Reduces Serum Neutralization

  Abstract Introduction Seasonal influenza causes significant global morbidity, mortality, and economic burden . Ongoing viral evolution can lead to vaccine mismatch and the emergence of antiviral resistance , highlighting the importance of genomic surveillance. The 2024–2025 influenza season was characterized by high incidence and increased hospitalizations. Methods We analyzed influenza A virus (IAV) genomes and clinical characteristics from the 2024–2025 season . Whole-genome sequencing was performed on 648 influenza A–positive clinical specimens collected between October 2024 and April 2025. Results Hemagglutinin (HA) sequences were recovered from 74.23% (481/648) of samples and used for subtyping and phylogenetic analysis. A(H1N1)pdm09 and A(H3N2) viruses co-circulated , representing 55.5% and 44.5% of cases, respectively. Among A(H1N1)pdm09 viruses, the HA1 substitution T120A , located near the Sa antigenic site , increased more than twofold compared with the prior season. Ci...

#Global #update on susceptibilities of #influenza viruses to #neuraminidase #inhibitors and the cap-dependent endonuclease inhibitor #baloxavir, 2020–2023

Highlights •  Antiviral susceptibility to NA inhibitors and PA inhibitor baloxavir was determined for seasonal and zoonotic influenza viruses circulating globally during 2020–2023. •  Low global frequencies (0.1-0.2%) of seasonal influenza viruses with reduced or highly reduced inhibition by NAI inhibitors were observed as in previous years. •  Low global frequencies of seasonal influenza viruses (∼ 0.1%) with reduced susceptibility to baloxavir were observed, with the rate in Japan elevated (3.3%) in 2022–2023, as has been seen previously. •  For zoonotic viruses, 2.7% contained genetic markers associated with reduced or highly reduced inhibition to NA inhibitors and none contained markers associated with reduced susceptibility for baloxavir. •  For the treatment of influenza , NA inhibitors and baloxavir remain suitable. ABSTRACT Antiviral susceptibility of influenza viruses is monitored by the World Health Organization Global Influenza Surveillance and Respon...

#WHO #clinical practice #guidelines for #influenza: an #update

Abstract Background Every year, more than one billion people around the world are infected with influenza , an acute infection of the respiratory tract. Influenza spreads from person to person through air, contaminated hands or objects. Antiviral and immunomodulatory drugs are available for treatment of patients and prophylaxis of exposed persons. Reverse transcription polymerase chain reaction (RT-PCR), nucleic acid amplification tests (NAATs) and rapid tests are available for the diagnosis of influenza.  Objective   The aim of this World Health Organization (WHO) guideline is to provide recommendations for the diagnosis, drug treatment and prophylaxis of influenza. Method This updated guideline has been developed in accordance with standards for trustworthy guidelines. The recommendations are based on systematic reviews on safety and effectiveness. They take into account the magnitude of benefits and harms of treatments, the reliability of the evidence, and the needs of pati...

A #monoclonal anti-hemagglutinin stem #antibody modified with #zanamivir protects against both #influenza A and B viruses

Significance Anti-influenza therapeutics remain essential for the control of influenza infections , which may require hospitalization for the most severe cases. Hemagglutinin (HA) and neuraminidase (NA), the two membrane glycoproteins of the influenza virus, play crucial roles in the viral replication cycle. While many monoclonal antibodies and small-molecule inhibitors target HA or NA, each faces limitations tied to their individual properties. We developed an antibody–drug conjugate (ADC) by covalently linking the NA inhibitor zanamivir to MEDI8852, an HA stem-specific monoclonal antibody . The MEDI8852–zanamivir conjugate targets both HA and NA and offers robust and long-lasting protection in mice against lethal infections with influenza A and B viruses. This approach represents an addition to anti-influenza therapy. Abstract Influenza remains a significant public health threat . Both monoclonal antibodies and small-molecule inhibitors can target the influenza surface glycoproteins ...

#Antiviral Susceptibility of #Influenza A(#H5N1) Clade 2.3.2.1c and 2.3.4.4b Viruses from #Humans, 2023-2024

Abstract During 2023-2024, highly pathogenic avian influenza A(H5N1) viruses from clade 2.3.2.1c caused human infections in Cambodia and from clade 2.3.4.4b caused human infections in the Americas . We assessed the susceptibility of those viruses to approved and investigational antiviral drugs . Except for 2 viruses isolated from Cambodia , all viruses were susceptible to M2 ion channel-blockers in cell culture-based assays. In the neuraminidase inhibition assay , all viruses displayed susceptibility to neuraminidase inhibitor antiviral drugs oseltamivir, zanamivir, peramivir, laninamivir , and AV5080. Oseltamivir was ≈4-fold less potent at inhibiting the neuraminidase activity of clade 2.3.4.4b than clade 2.3.2.1c viruses. All viruses were susceptible to polymerase inhibitors baloxavir and tivoxavir and to polymerase basic 2 inhibitor pimodivir with 50% effective concentrations in low nanomolar ranges. Because drug-resistant viruses can emerge spontaneously or by reassortment, close m...

Evaluation of #influenza #antiviral #prophylaxis for long-term care residents: a systematic review and meta-analysis

Abstract Background Influenza is a pervasive respiratory infection which disproportionately burdens long-term care residents. To limit outbreaks, guidelines recommend antiviral prophylaxis, particularly oseltamivir or zanamivir , despite acknowledging the inadequate supporting evidence . Therefore, we aimed to review the literature on the efficacy of oseltamivir, zanamivir, and baloxavir prophylaxis for influenza in long-term care. Methods Medline, Embase, PubMed, and several other databases were searched from inception to August 16, 2023. For inclusion, observational studies or randomized controlled trials (RCTs) had to report influenza-like illness (ILI) or infection rates amongst adult long-term care populations receiving prophylaxis. Outcome values were meta-analyzed as intervention-specific pooled proportions (PPs) and risk ratios (RRs) when applicable. Risk of bias was assessed via the Cochrane risk of bias tool 2.0 and Joanna Briggs Institute checklist. Results In total, 14 stud...

Highly Pathogenic Avian #Influenza A(#H5N1) Virus: Interim #Recommendations for #Prevention, #Monitoring, and Public Health #Investigations

Summary The purpose of this guidance is to outline CDC's recommendations for preventing exposures to highly pathogenic avian influenza (HPAI) A(H5N1) viruses, infection prevention and control measures including the use of personal protective equipment , testing, antiviral treatment , patient investigations , monitoring of exposed persons (including persons exposed to sick or dead wild and domesticated animals and livestock with suspected or confirmed infection with highly pathogenic avian influenza (HPAI) A(H5N1) virus), and antiviral chemoprophylaxis of exposed persons. These recommendations are based on available information and will be updated as needed when new information becomes available. (...) Source: US Centers for Disease Control and Prevention,  https://www.cdc.gov/bird-flu/prevention/hpai-interim-recommendations.html _____