#zanamivir — Public Fediverse posts

#Zanamivir - #Amantadine Conjugate: A Dual-Action Agent with Broad-Spectrum Synergistic #Antiviral Efficacy, https://etidiohnew.blogspot.com/2026/02/zanamivir-amantadine-conjugate-dual.html

A #monoclonal anti-hemagglutinin stem #antibody modified with #zanamivir protects against both #influenza A and B viruses, https://etidiohnew.blogspot.com/2025/04/a-monoclonal-anti-hemagglutinin-stem.html

A #monoclonal anti-hemagglutinin stem #antibody modified with #zanamivir protects against both #influenza A and B viruses, https://etidiohnew.blogspot.com/2025/04/a-monoclonal-anti-hemagglutinin-stem.html

A #monoclonal anti-hemagglutinin stem #antibody modified with #zanamivir protects against both #influenza A and B viruses, https://etidiohnew.blogspot.com/2025/04/a-monoclonal-anti-hemagglutinin-stem.html

A #monoclonal anti-hemagglutinin stem #antibody modified with #zanamivir protects against both #influenza A and B viruses, https://etidiohnew.blogspot.com/2025/04/a-monoclonal-anti-hemagglutinin-stem.html

A #monoclonal anti-hemagglutinin stem #antibody modified with #zanamivir protects against both #influenza A and B viruses, https://etidiohnew.blogspot.com/2025/04/a-monoclonal-anti-hemagglutinin-stem.html

13th #Meeting of #WHO Expert Working #Group on #Surveillance of #Antiviral Susceptibility of #Influenza Viruses for WHO #GISRS

Source: World Health Organization, Weekly Epidemiological Record: https://www.who.int/publications/journals/weekly-epidemiological-record

{Excerpt, edited}

Executive summary

The WHO Expert Working Group on Surveillance of Influenza Antiviral Susceptibility (AVWG) supports the WHO Global Influenza Surveillance and Response System (GISRS) by providing practical guidance for monitoring the antiviral susceptibility of seasonal and emerging influenza viruses The 13th WHO AVWG meeting was held in hybrid format (faceto-face and virtually) on 13–14 June 2024 in Lyon, France.

Update on susceptibility of seasonal influenza viruses to approved antiviral agents

Between May 2023 and May 2024, WHO collaborating centres (CCs) and participating national influenza centres (NICs) reported that seasonal influenza activity in various regions had resumed to levels before the coronavirus disease 2019 (COVID-19) pandemic. Co-circulation of A(H1N1)pdm09, A(H3N2) and influenza B/Victoria lineage viruses was detected in most regions. Overall, influenza A and B viruses with reduced inhibition (RI) or highly reduced inhibition (HRI) to neuraminidase (NA) inhibitors (NAIs) were detected at low frequency. The most frequently identified substitution associated with RI or HRI by NAIs was NA-H275Y in A(H1N1)pdm09 viruses, which was detected at <2%. Double amino acid substitutions (NA-I223V+ NA-S247N) in A(H1N1)pdm09 viruses (referred to as dual mutant viruses) that resulted in RI by oseltamivir were first detected in May 2023 and spread rapidly to several regions of the world.{1,2} Influenza A and B viruses with amino acid substitutions in the polymerase acidic (PA) protein associated with reduced susceptibility to endonuclease inhibitor (baloxavir) were detected at low frequency. The PA-I38X (including I38T, I38N, I38M and I38V) amino acid substitution being the most frequently reported, but the overall detection frequency has remained low (<2%).

Update on susceptibility of zoonotic and animal influenza viruses to approved antiviral agents

From May 2023 to May 2024, clade 2.3.4.4b A(H5N1) highly pathogenic avian influenza (HPAI) viruses continued to be detected in various regions of the world. Since early 2024, there has been an outbreak of clade 2.3.4.4b A(H5N1) genotype B3.13 viruses in dairy cattle in several states in the United States of America, resulting in sporadic zoonotic infections in humans. In addition, human infection with clade 2.3.2.1c A(H5N1) HPAI has been reported in Cambodia and Viet Nam. WHO CCs, participating NICs and WHO H5 reference laboratories reported antiviral susceptibility testing of A(H5N1) HPAI, low pathogenic avian influenza (LPAI) of various subtypes and swine influenza viruses. Of the clade 2.3.4.4b A(H5N1) HPAI viruses, the NA-T438I substitution, which confers RI by zanamivir and peramivir, was detected at <2% frequency. NA-H275Y, NA-N295S and NA-N295S+NA-T438N associated with RI or HRI by NAIs were also detected among A(H5N1) viruses. NA-T438I has been detected in A(H5N1) viruses isolated from dairy cattle. PA-I38T, PA-A37T and PA-I38M, associated with reduced susceptibility to baloxavir, were detected in A(H5N1) viruses. Most A(H5N1) HPAI viruses remain susceptible to M2 ion channel blockers. Among LPAI, NA-H274Y with HRI by oseltamivir was detected in one A(H8N4) isolate. PA-E199G with reduced susceptibility to baloxavir was detected in one A(H9N2) virus. Overall, animal or zoonotic influenza viruses with reduced susceptibility to NAIs or baloxavir were detected at very low frequencies.

Update of protocols and guidance for GISRS laboratories

Genotypic and/or phenotypic assays can be used to monitor the susceptibility of influenza viruses to NAIs and baloxavir. The WHO AVWG routinely reviews and updates information on NA{3,4} and PA{5} amino acid substitutions associated with reduced susceptibility to NAIs and baloxavir, respectively. Reference virus panels that can be used for NAI and baloxavir susceptibility testing are available for GISRS laboratories at the International Reagent Resource.{6} The WHO AVWG will develop an algorithm for NICs to decide on testing strategies (genotypic versus phenotypic) and methods according to their capacity. Guidance on phenotypic assays for NAI susceptibility testing is provided in a WHO guidance document to NICs, which was updated in 2018.{7} A new phenotypic assay has been developed for testing susceptibility to baloxavir.{8} The protocol will be posted on the WHO website. The WHO-AVWG will also update the WHO guidance document to NICs to include the new phenotypic assay for baloxavir susceptibility testing. In addition, the WHO AVWG will work with the Global Initiative on Sharing All Influenza Data{9} to facilitate identification of NA and PA substitutions in submitted sequences.

Review of external quality assessment programme (EQAP) panels

EQAP was initiated in 2007, and the antiviral panel was introduced in 2013 (panel 12) as an optional component of EQAP to evaluate the ability of NICs to identify influenza viruses with reduced susceptibility to NAIs. Genotypic testing for baloxavir susceptibility was introduced in 2020 (panel 19) for educational purpose (i.e. not scored). Results for the 2023 Global EQAP panel were reported at the 13th WHO AVWG meeting. A total of 178 laboratories participated in the 2023 EQAP; 46 (25.8%) participated in NAI susceptibility testing and 16 (9.0%) in baloxavir susceptibility testing. The results from the Global EQAP antiviral panel are used by members of the WHO AVWG to assess the training requirements of NICs.

Way forward

Two reports, on global antiviral surveillance in 2020-2023 and in 2023–2024, are being prepared for publication. The next WHO AVWG meeting is scheduled for June 2025.

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{1} Leung RC et al. Global emergence of neuraminidase inhibitor-resistant influenza A(H1N1)pdm09 viruses with I223V and S247N mutations: implications for antiviral resistance monitoring. Lancet Microbe. 2024;5(7):627–8. doi:10.1016/S26665247(24)00037-5.

{2} Patel MC et al. Multicountry spread of influenza A(H1N1)pdm09 viruses with reduced oseltamivir inhibition, May 2023-February 2024. Emerg Infect Dis. 2024;30(7):1410–5. doi:10.3201/eid3007.240480.

{3} Summary of neuraminidase (NA) amino acid substitutions associated with reduced inhibition by neuraminidase inhibitors (NAIs). Geneva: World Health Organization; 2023 (https://www.who.int/publications/m/item/summary-of-neuraminidase-(na)-amino-acid-substitutions-associated-with-reduced-inhibition-by-neuraminidase-inhibitors-(nais).

{4} Summary of neuraminidase (NA) amino acid substitutions associated with reduced inhibition by neuraminidase inhibitors (NAIs) among avian influenza viruses of Group 1 and Group 2 NAs. Geneva: World Health Organization; 2024 (https://www. who.int/publications/m/item/summary-of-neuraminidase-(na)-amino-acid-substitutions-associated-with-reduced-inhibition-by-neuraminidase-inhibitors-(nais)among-avian-influenza-viruses-of-group-1-and-group-2-nas).

{5} Summary of polymerase acidic (PA) protein amino acid substitutions analysed for their effects on baloxavir susceptibility. Geneva: World Health Organization; 2024 (https://www.who.int/publications/m/item/summary-of-polymerase-acidic-(pa)-protein-amino-acid-substitutions-analysed-for-their-effects-on-baloxavirsusceptibility).

{6} See https://www.internationalreagentresource.org.

{7} Practical guidance for national influenza centres establishing or implementing neuraminidase inhibitor susceptibility surveillance. Geneva: World Health Organization; 2024 (https://www.who.int/publications/i/item/practical-guidance-for-national-inf luenza-centres-establishing-or-implementing-neuraminidase-inhibitor-susceptibility-surveillance).

{8} Baloxavir susceptibility assessment using influenza replication inhibition neuraminidase-based assay (IRINA). Atlanta (GA): Centers for Disease Control and Prevention; 2023 (https://cdn.who.int/media/docs/default-source/influenza/avwg/ cdc-phenotypic-lp-492rev01d—baloxavir-susceptibility-assessment-using-irina. pdf?sfvrsn=f24254ac_3).

{9} See https://gisaid.org.

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#aH3n2 #aH5n1 #aH9n2 #amantadine #antivirals #AVIANINFLUENZA #baloxavir #birdFlu #drugsResistance #h1n1pdm09 #h5n1 #health #influenza #oseltamivir #science #SEASONALINFLUENZA #updates #WHO #zanamivir

#Antivirals for #PEP of #influenza: a systematic #review and network meta-analysis https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(24)01357-6/fulltext?rss=yes

PEP with #zanamivir, #oseltamivir, #laninamivir, or #baloxavir probably decreases #risk of symptomatic seasonal flu in individuals at high risk for severe disease after exposure to seasonal flu viruses. PEP with zanamivir, oseltamivir, laninamivir, or baloxavir might reduce risk of symptomatic #zoonotic flu after exposure to novel viruses associated with severe disease in infected humans.

#Molecular #surveillance of #influenza A virus in #SaudiArabia: #WGS and metagenomic approaches https://pubmed.ncbi.nlm.nih.gov/38904365/?utm_source=Feedly&utm_medium=rss&utm_campaign=None&utm_content=10ykRO9og5pGdo51l9DEPEpOJ3DVFIn__QK2QPM3dci1C1dEYq&fc=None&ff=20240621125233&v=2.18.0.post9+e462414

One sample containing the #antiviral #resistance-mediating #mutation #S247N toward #oseltamivir and #zanamivir was found.

#h5n1 #birdflu #avianflu #hpai #h5n2 #influence #grippe #flu #press #news

#antivirale #Medikamente #Virostatika geg #Influenza:

#Oseltamivirphosphat (als Generikum od. unter Handelsnamen #Tamiflu)
#Zanamivir ( #Relenza )
#Peramivir ( #Rapivab )
#Baloxavir ( #Xofluza )
Bei bestätigter od. Verdacht auf #Vogelgrippe wird schnellstmögl. Behandlung empfohlen

Tiermodelle & #Beobachtungsstudien deuten auf Nutzen von Virostatika bei mit Vogelgrippe infizierten #Menschen hin

https://www.medscape.com/viewarticle/new-human-cases-avian-flu-anticipated-2024a1000bfg?form=fpf

#Duration of #fever in #children infected with #influenza #H1N1pdm09, #H3N2 or B virus & treated with #baloxavir, #oseltamivir, #laninamivir, or #zanamivir in #Japan during the 2012–13 & 2019–20 seasons, Antiviral Res.: https://www.sciencedirect.com/science/article/pii/S0166354224001475?via%3Dihub

We compared fever duration between baloxavir- & 3 NAIs-treated groups. ...For influenza A, fever duration in baloxavir- & NAIs-treated groups was similar. For influenza B, fever duration was ∼15 h shorter in baloxavir-treated group.

#Antivirals for #PEP of #influenza: a systematic #review and network meta-analysis, MedRxIV, https://www.medrxiv.org/content/10.1101/2024.05.28.24307995v1

Post-exposure #prophylaxis with #zanamivir, #oseltamivir, #laninamivir or #baloxavir might reduce the #risk of symptomatic #zoonotic influenza after exposure to novel influenza A viruses associated with severe disease in infected humans.

''In 2022, flu #H3N2 viruses predominated over #H1N1pdm09 & B viruses, accounting for 77% of all viruses analysed. Majority of #H1N1pdm09, #H3N2 & flu B viruses analysed at Centre were found to be antigenically and genetically similar to respective #WHO recommended #vaccine #strains for the S hemisphere in 2022. Of 3,372 samples tested for susceptibility to the #NAIs #oseltamivir & #zanamivir, 2 H1N1pdm09 viruses showed highly reduced inhibition against oseltamivir.''

''Phenotypic testing of 22 clade 2.3.2.1a and 2.3.4.4b viruses revealed broad susceptibility to NAIs and #baloxavir concluding that most contemporary HPAI A(#H5N1) viruses retain susceptibility to #antiviral drugs. Novel NA-K432E and NA-T438I #substitutions (N2 numbering) were identified at **elevated frequencies** (104/2698, 3.85%) and caused reduced #zanamivir and #peramivir inhibition.''