Prevention and treatment of respiratory viral infections_ Presentations on antivirals, traditional

25 Pages·2017·0.49 MB·English

Antiviral Research 149 (2018) 118–142
ContentslistsavailableatScienceDirect
Antiviral Research
journal homepage: www.elsevier.com/locate/antiviral
Meeting Report
Preventionandtreatmentofrespiratoryviralinfections:Presentationsonantivirals,traditionaltherapiesandhost-
directedinterventionsatthe5thISIRVAntiviralGroupconference
A R T I C L E I N F O A B S T R A C T
Keywords: TheInternationalSocietyforInfluenzaandotherRespiratoryVirusDiseasesheldits5thAntiviralGroup(isirv-
Influenza AVG) Conference in Shanghai, China, in conjunction with the Shanghai Public Health Center and Fudan
RSV Universityfrom14-16June2017.Thethree-dayprogrammeencompassedpresentationsonsomeoftheclinical
Antivirals features,management,immuneresponsesandvirologyofrespiratoryinfections,includinginfluenzaA(H1N1)
Vaccines
pdm09andA(H7N9)viruses,MERS-CoV,SARS-CoV,adenovirusType80,enterovirusD68,metapneumovirus
Isirv-AVG
andrespiratorysyncytialvirus(RSV).Updateswerepresentedonseveraltherapeuticscurrentlyinclinicaltrials,
includinginfluenzapolymeraseinhibitorspimodivir/JNJ6362387,S033188,favipiravir,monoclonalantibodies
MHAA45449AandVIS410,andhostdirectedstrategiesforinfluenzaincludingnitazoxanide,andpolymerase
ALS-008112andfusioninhibitorsAK0529,GS-5806forRSV.Updateswerealsogivenontheuseofthecurrently
licensed neuraminidase inhibitors. Given the location in China, there were also presentations on the use of
TraditionalChineseMedicines.Followingonfromthepreviousconference,therewereongoingdiscussionson
appropriateendpointsforsevereinfluenzainclinicaltrialsfromregulatorsandclinicians,anissuewhichre-
mainsunresolved.Theaimofthisconferencesummaryistoprovideinformationfornotonlyconferencepar-
ticipants,butadetailedreferencedreviewofthecurrentstatusofclinicaltrials,andpre-clinicaldevelopmentof
therapeuticsandvaccinesforinfluenzaandotherrespiratorydiseasesforabroaderaudience.
Background
Influenzaandotheracuterespiratoryvirusdiseasesareofmajorglobalpublichealthimportance.Theemergenceofthepandemicinfluenzain
2009, the increasing numbers of human cases of avian influenza A(H7N9) virus infections in China, the emergence of Middle East Respiratory
Syndromecoronavirus(MERS-CoV),continuedoutbreaksofhighlypathogenicinfluenzaA(H5N1)virusesinseveralcountries,andnovelstrainsof
influenza now infecting humans, highlights the importance ofinternational collaboration on respiratory virus research anddevelopment of new
strategiesfortheirpreventionandcontrol.TheInternationalSocietyforInfluenzaandotherRespiratoryVirusesDiseases(isirv)isanindependent
andinternationalscientificprofessionalsocietypromotingtheprevention,detection,treatment,andcontrolofinfluenzaandotherrespiratoryvirus
diseases.TheAntiviralGroupisaspecialinterestgroupofisirv(isirv-AVG)withspecificobjectivestopromoteunderstandingoftheclinicaluseof
antiviralsagainstrespiratoryviruses,andtocollateandprovideuptodateinformationontheemergenceofantiviralresistancetotheestablished
therapeutics.Italsoaimstoprovideinformationontheevaluationofresistancetonewtherapiesunderdevelopment.Tocommunicateadvancesin
preclinicalandclinicaldevelopmentofpotentnovelantiviralsfourpreviousconferenceshavebeenorganizedbytheisirv-AVG.
The5thisirv-AVGConferencewasheldinShanghai,China,inconjunctionwiththeShanghaiPublicHealthCenterandFudanUniversityfrom
14-16 June 2017. The three-day programme encompassed presentations on some of the clinical features, management, immune responses and
virology of respiratory infections, including influenza A(H1N1)pdm09 and A(H7N9), MERS-CoV, severe acute respiratory syndrome coronavirus
(SARS-CoV), adenovirus Type 80, enterovirus D68, metapneumovirus and respiratory syncytial virus (RSV). Updates were presented on several
therapeutics currently in clinical trials, including polymerase inhibitors, monoclonal antibodies and host directed strategies for influenza, and
polymeraseandfusioninhibitorsforRSV.Updateswerealsogivenontheuseofthecurrentlylicensedneuraminidaseinhibitors(NAIs).
GiventhelocationinChina,therewerealsopresentationsontheuseofTraditionalChineseMedicines(TCM).WhileTCMshavebeenusedfor
thousands of years, and some may show benefits for treatments of respiratory virus infections, their development is complicated due to their
formulationandcombinationsofcompounds.Thepotencyofherbalmedicationsmayalsovaryfrommanufacturertomanufacturerandfromlotto
lot.Forthesafeandeffectiveuseofherbalmedicines,standardizingherbalformulationsisessentialforconsistencyincompositionandcomparable
clinical effectiveness. Additionally, meta-analysis of efficacy of TCM in respiratory virus infections has emphasized the need for evidence based
medicine,especiallyplacebocontrolledtrials(Chenetal.,2011).InvitroandsomeclinicaldataarepresentedonthecommonlyusedTCM.
Abbreviations:ARDS,Acuterespiratorydistresssyndrome;AUC,Areaunderthecurve;CAP,Communityacquiredpneumonia;HA,hemagglutinin;HPAI,Highlypathogenicavian
influenza;LPM,Livepoultrymarkets;MERS-CoV,MiddleEastrespiratorysyndromecoronavirus;MN,microneutralization;NA,neuraminidase;NAI,neuraminidaseinhibitor;PCT,
Placebocontrolledtrial;PRNT,plaquereductionneutralizationtiter;RDB,randomizeddoubleblind;S/ARI,Severe/Acuterespiratoryinfection;SARS-CoV,Severeacuterespiratory
syndromecoronavirus;TCID50,50%tissuecultureinfectivitydose
https://doi.org/10.1016/j.antiviral.2017.11.013
Received9November2017;Accepted14November2017
Available online 21 November 2017
0166-3542
MeetingReport Antiviral Research 149 (2018) 118–142
Followingonfromthepreviousconference,therewereongoingdiscussionsonappropriateendpointsforsevereinfluenzainclinicaltrialsfrom
regulatorsandclinicians,anissuewhichremainsunresolved.Theaimofthisconferencesummaryistoprovideinformationfornotonlyconference
participants, but a review of the current status of clinical information, and development of therapeutics and vaccines for influenza and other
respiratorydiseases.
1. Keynote:zoonoticrespiratoryviralthreatsattheanimal-humaninterface
MalikPeiris,SchoolofPublicHealth,theUniversityofHongKong,HongKong,China
Around70%ofemerginghumaninfectiousdiseaseshavearisenfromanimalreservoirs.Severalviruseswithglobalpandemicpotentialinclude
SARS-CoV, MERS-CoV, vector-borne viruses (Zika virus, but also Dengue and Chikungunya viruses), and Ebola virus. For influenza viruses, an
increasednumberofhumaninfectionswithavianA(H7N9)viruses,andappearanceofasub-lineagethathasacquiredfeaturesofhighlypathogenic
avianinfluenza(HPAI)arerecentnotableevents(Keetal.,2017;Suetal.,2017).Livepoultrymarkets(LPM)remainthemostlylikelysourceof
A(H7N9) infection, with 67% of patients exposed to an LPM, versus 33% with no history of exposure. HPAI A(H5N6) (Zhou et al., 2016) and
A(H5N1) viruses continue to pose zoonotic threats. Influenza A(H5N8) viruses, though currently not causing zoonotic disease, continue to dis-
seminate via wild bird migration. Responses to control of emerging influenza infections include: 1) early detection; 2) control at source (i.e.
interruptionofvirustransmissionchainatretailandwholesaleLPM);and3)innovationinpredictingemergenceofinfluenzaviruseswithpandemic
potential.Newhigh-throughputtechnologiesandimproveddiagnosticcapacityareessentialforbettercontrol.LPMremainhubsforvirusampli-
fication,persistenceanddisseminationwithinpoultryaswellasourceoftransmissiontohumans.Ahighlevelofcontaminationofchickencarcasses
withinfectiousavianinfluenzaviruses(39.8%of1230samples)wasalsodetectedeitherattheretailLPMoratthedressedpoultrystalls(Maoetal.,
2017).ViralRNAorinfectiousavianinfluenzavirusesofH5,H7andH9subtypesweredetectedinairsamplesfromLPMinGuangzhouandHong
KongSAR,andtheuseofde-featheringdevicesincreasedthequantityofvirus-ladenairborneparticles(Zhouetal.,2016).Thus,bothdirectcontact
with live poultry, and airborne transmission of avian influenza viruses can increase zoonotic risks. Interventions to reduce risk of novel virus
emergenceinLPM,suchasmarketrest-days(orevenclosure),banoflivepoultrystallsinurbanareaswithcentralslaughteringandsalesofpoultry
carcasses,havebeenimplementedinChina(Peirisetal.,2016;Yuanetal.,2015).
Influenza A viruses ofswine can also be zoonotic pathogens. Influenza viruses ofswine in China now carrymultiple internal gene segments
derivedfromtheA(H1N1)pdm09virus(Baudonetal.,2017).MostoftheseareH1orH3subtypevirusestowhichthereishumanpopulationcross-
immunity,butthepossibilitythatswineviruseswiththeA(H1N1)pdm09internalgenecassettemayacquireavianinfluenzahemagglutinin(HA)or
neuraminidase(NA)genesthroughgeneticreassortmentisaconcern.Althoughitisdifficulttoaccuratelypredictthepandemicthreatofavirus,
systematic algorithms addressing the risk that an avian or animal virus will achieve sustained human-to-human transmission and emerge as a
pandemic (IRAT, TIPRA) have been developed (Trock et al., 2015). Such risk-assessments will need to be made on a continuing basis for pre-
pandemicvaccinestrainselection.
MERS-CoVisendemicindromedarycamelsthroughouttheMiddleEast,SouthAsiaandinWest,NorthandEastAfrica,althoughzoonoticdisease
has only been reported from the Arabian Peninsula (Hemida et al., 2017). It is estimated that more than 45,000 people in Saudi Arabia are
seropositive,howeverasmildcasesdonotseemtoinducehighlevelsofneutralizingantibody,manymoremayhavebeeninfected.Incontrast,
althoughmanydromedarycamelsinAfricaarebothvirusandseropositive,thediseaseisnotseen.Reasonsforthisepidemiologicalpatternmay
include viral genetic heterogeneity, cultural differences in interactions with camels or lack of diagnosis of human MERS-CoV. The continuous
surveillanceofMERS-CoVinanimalreservoirs,rapididentificationandcharacterizationofnovelpathogensandtheirhostinteractionsisrequiredas
itwilldecreasethepotentialvirusthreattohumanhealth.
2. Novelcoronaviruses
2.1. Insightsfrompre-clinicalmodelsofMERS-CoVandSARS-CoV
RalphS.Baric,UniversityofNorthCarolinaatChapelHill,NC,USA
Coronaviruses(CoVs)areenvelopedviruseswithapositive-sensesingle-strandedRNAgenomeandcaninfecthumansandanimals.SARS-CoV
andMERS-CoVarenewlyemergedCoVscausingsevereepidemicrespiratorydiseaseinhumanpopulationswithhighmortality(Channappanavar
andPerlman,2017).SomeSARS-likeviruses,suchasSHC014-CoV,whichiscurrentlycirculatinginChinesehorseshoebatpopulations(Geetal.,
2013)mayalsoevolveintoahumanCoVwithpotentialtocauseglobalpandemicsinthefuture(Menacheryetal.,2015).
UsingCRISPR-Cas9geneeditingtomodifythemousegenomeforexpressinghumandipeptidylpeptidase4(DPP4)theMERS-CoVco-receptor,a
pre-clinicalmousemodelsusceptibletoMERS-CoVinfectionandreplicationwasdeveloped.Infectionwithamouse-adaptedMERS-CoVresultedin
symptomsindicativeofsevereacuterespiratorydistresssyndrome(ARDS).TreatmentoftheseengineeredmicewithMERS-CoVneutralizingan-
tibodiesorvaccinationwithaMERS-CoVspikeproteincouldprotectagainstMERS-CoV-inducedARDS(Cockrelletal.,2016).
To combat diseases caused by current and future human CoVs broad-spectrum therapies capable of inhibiting CoV infections are needed. A
nucleotideprodrug,GS-5734,currentlyinclinicaldevelopmentfortreatmentofEbolavirusdisease,inhibitedreplicationofSARS-CoVandMERS-
CoVinseveralinvitroassaysystems,includingprimaryhumanairwayepithelialcellcultureswithsubmicromolarIC values.Interestingly,GS-5734
50
isalsoeffectiveagainstbatCoVs,prepandemicbatCoVs,andcirculatingcontemporaryhumanCoVinprimaryhumanlungcells.Inamousemodel
ofSARS-CoVpathogenesis,prophylacticandearlytherapeuticadministrationofGS-5734significantlyreducedlungviralloadandimprovedclinical
signsofdiseaseaswellasrespiratoryfunction.ThesefindingssuggestthatGS-5734possessesbroad-spectrumanti-CoVactivityandhaspotentialto
bedevelopedasanoveltherapyfortreatmentofinfectionbyendemicMERS-CoV,circulatinghumanCoVs,andpossiblytheemergingCoVsofthe
future(Sheahanetal.,2017).
2.2. ClinicalfeaturesandthevirologiccourseofMERS
Myoung-donOh,SeoulNationalUniversityCollegeofMedicine,Seoul,SouthKorea
OnMay4th,2015,MERS-CoVwasimportedbyareturningtravellerfromtheMiddleEasttoSeoul.Subsequently,thevirusspreadwithinthe
hospitalsinSeoul,resultingin186casesofconfirmedinfection,including38fatalities(Kangetal.,2017).Age>55yearsoldwasthegreatestrisk
119
MeetingReport Antiviral Research 149 (2018) 118–142
factor.Duringtheepidemiclasting2months,16,993individualswerequarantinedfortwoweekswithanestimatedeconomiccostof8.3billion
USD. A total of 17 patients were categorized into severe and mild groups, depending on whether oxygen supplementation was used during the
hospitalstay.ViralloadinthesepatientsanalyzedbyrRT-PCRfoundthatMERS-CoVconcentrationspeakedduringthe2ndweekofillness.The
severe group had higher viral loads than those in the mild group. The patients in the severe group also had more prolonged viral shedding in
respiratorysecretionsthanthoseinthemildgroup.Importantly,lowerrespiratorytractspecimenshadhigherandmoreprolongedlevelsofMERS-
CoVRNAthanthosefromupperrespiratorytract.10%ofpatientswerestillPCRpositiveatday28.Throatswabsmaybeanalternativesourceof
diagnosticsampleswhensputumcannotbeobtained(Ohetal.,2016).Aftersequencingfullviralgenomesofstrainsisolatedfrom4patientsearly
and late during infection, who represented at least 4 generations of transmission, it was found that there was no evidence of changes in the
evolutionaryrateandnoadaptivechangesinviralproteins(Seongetal.,2016).
NosocomialtransmissionisanimportantcharacteristicofMERS-CoVinfection.RiskfactorsfortransmissionofMERS-CoVinhealthcaresettings
arenotwelldefined.The186patientswhohadlaboratory-confirmedMERS-CoVinfectionaresuspectedasasourceofviraltransmission.Theycould
becategorizedintothreespreadergroups,including5super-spreaders,10usual-spreaders,andthenon-spreadersgroup(n=171).Thesignificant
riskfactorsinthespreadergroupinclude:1)hightemperature(≥38.5°C),2)pulmonaryinfiltration(≥3lungzones),andmorenon-isolatedin-
hospitaldays.Thesuper-spreadershadmorenon-isolatedin-hospitaldaysthantheusual-spreaders(Mean,6.6vs.2.9days),suggestingthatearly
activequarantinemighthelpreducethesizeofanoutbreak(Kangetal.,2017).
2.3. AdvancesindevelopingvaccinesandtherapeuticsagainstMERS-CoV
ShiboJiang,CollegeofBasicMedicalSciences,FudanUniversity,Shanghai,China
TodatetherearenovaccinesortherapeuticsforpreventionandtreatmentofMERS-CoVinfection.Previousstudieshaveshownthatthereceptor-
binding domain (RBD) in the S1 subunits of SARS-CoV spike (S) protein plays an important role in mediating virus binding to its receptor, an-
giotensinIconvertingenzyme2(ACE2),andcontainsthecriticalneutralizingdomain,thusservingasanimportanttargetfordevelopingaSARS-
CoVvaccine(Duetal.,2009;Heetal.,2005).Similarly,theRBDinMERS-CoVSproteincanalsoeffectivelybindtoitsreceptor,DPP4,andinduce
potentneutralizingantibodyresponsesintheRBD-immunizedmice(Duetal.,2013b).AsubunitvaccinewasengineeredbylinkingMERS-CoVS-
RBDwiththeFcofhumanIgG(RBD-Fc)(Duetal.,2013a).ThetransgenicmicethatgloballyexpressedhumanDPP4(hDPP4-Tg)immunizedwith
RBD-FcwerefullyprotectedfromlethalMERS-CoVchallenge(Taoetal.,2015).ThisRBD-Fcsubunitvaccinewasfurtheroptimizedusingimmune
refocusing and “neutralizing immunogenicity index” (NII) strategies (Du et al., 2016) suggesting that this vaccine candidate has potential to be
furtherdevelopedasaneffectiveandsafesubunitvaccineforpreventionofMERS-CoVinfection.
Based on theprevious experience indeveloping peptide fusion inhibitors against HIV(Jiang et al.,1993) andSARS-CoV (Liu et al.,2004) a
peptidederivedfromtheS2subunitHR2domainsofMERS-CoVSprotein,designatedHR2P,wasfoundtobeveryeffectiveininhibitingMERS-CoVS
protein-mediatedcell-cellfusionandinfectionbybothpseudotypedandliveMERS-CoVwithanIC atthenMlevel(Luetal.,2014).HR2Pandits
50
analogouspeptides,suchasHR2P-M2,haveshownexcellentinvitroandinvivoefficacyagainstMERS-CoVinfection(Channappanavaretal.,2015)
andprotectedhDPP4-TgmicefromlethalMERS-CoVchallenge(Taoetal.,2015).
UsingMERS-CoVS-RBDtoimmunizemice,aneutralizingmonoclonalantibody(mAb)designatedMersmab1,wasidentified.ThismAbspeci-
ficallybindstoMERS-CoVS-RBDandcompetitivelyinterfereswiththebindingoftheRBDtoitscellularreceptorDPP4,thuseffectivelyblocking
MERS-CoVentryintothehostcellsandpotentlyneutralizingMERS-CoVinfection(Duetal.,2014).
Using MERS-CoV S-RBD to screen a very large naïve-antibody library (containing ∼1011 antibodies), a series of RBD-specific human mAbs,
includingm336,m337,andm338,werediscovered.ThesemAbsboundMERS-CoVS-RBDwithhighaffinityandavidity.Theyboundtoepitopesthat
overlapthereceptorbindingsiteontheRBD.Thehighest-affinitymAb,m336,isexceptionallypotentinneutralizingbothpseudotypedandlive
MERS-CoV with 50% neutralization at pM level (Ying et al., 2014). The hDPP4-Tg mice treated with m336 prior to or post lethal MERS-CoV
challengewerefullyprotected(Agrawaletal.,2016).X-raycrystallographicanalysisofthestructureofFabm336incomplexwithMERS-CoVS-RBD
revealsthatitsepitopealmostcompletelyoverlapswiththeRBD.Mostinterestingly,thishumanmAbisalmostgermlinewithonlyonesomatic
mutationintheheavychain(Yingetal.,2015),suggestingthatitcanbesafelyusedinhumans.
3. Emergingthreats
3.1. LessonsfromnosocomialoutbreaksofMERS
Sang-WonPark,SeoulNationalUniversityCollegeofMedicine,Seoul,SouthKorea
TheKoreanoutbreakofMERS-CoVin2015resultingin186caseswithacasefatalityrateof19.4%isthelargestoutbreakoutsidetheMiddleEast
(Oh et al., 2016). The major factors contributing for this nosocomial outbreak include: 1) overcrowded emergency departments, 2) delays in
diagnosis,3)substandardpracticesforinfectioncontrol,4)theneglectofemergingandre-emergingglobalinfectiousdiseases,and5)thelackof
infrastructure for highly contagious infectious diseases and hospital infection control. Therefore, this outbreak should serve as momentum for
governmentreformofthehealthcaresystemininfectiousdiseases.
ThekineticsofserologicresponsestoMERS-CoVinfectionwereassessedbytesting95serafrom17MERSpatientscollected2–46daysafter
symptomonsetbyusingplaquereductionneutralizationtests,microneutralization(MN),MERS-spikepseudoparticleneutralizationandMERSS1-
enzyme-linkedimmunosorbentassay(ELISA).Inmostpatients,robustantibodyresponsesdevelopedbythethirdweekofillness.Neutralizationtests
correlated well with each other and moderately well with S1ELISA. Delayed neutralizing antibody responses were associated with more severe
disease(Choeetal.,2017;Parketal.,2015a,2015b).
3.2. Humanadenovirustype80:anoveladenoviruscausingARDSanddisseminatedinfectionwithfataloutcome
BarbaraRath,ViennaVaccineSafetyInitiative,Berlin,Germany
Adenoviruses,whicharenonenvelopedviruseswithadoublestrandedDNAgenome,werefirstisolatedfromhumanadenoidsin1953.Morethan
50distinctadenoviralserotypescaninfecthumans,causingavarietyofdiseasesrangingfrommildrespiratoryinfectiontolife-threateningmulti-
organ disease (Smith et al., 2010). Neonatal adenovirus infection is a rare and fatal disease (Elnifro et al., 2005). Particularly, disseminated
120
MeetingReport Antiviral Research 149 (2018) 118–142
adenovirusinfectionmaycauseARDSwithfataloutcomesininfantsandneonatesinintensivecareunits.FromOctober2009toApril2015,6073
patients (infants and children with mean age 3.1 years, range 0–18.8 years) in intensive care units, who presented with fever ≥38 °C and ≥1
respiratory symptom(s) and/orphysician diagnosesofinfluenza-like illness,weretested foradenovirus infection. Itwasfoundthat584 ofthese
patientstestedadenovirus-positive(meanage2.2years,range0–17.5,92% < 5years),whileonly4adenovirusinfectionsoccurredinneonates
aged≤28days.OneofthesefourneonatesdevelopeddisseminatedadenoviraldiseasewithARDSandfataloutcome.Wholegenomesequencing
revealed that this infant was infected by a novel human adenovirus type 80, although the pathogenesis of this novel virus and the host factors
contributingtodiseaseseverityhavenotbeendefinedyet.Therefore,timelydetectionofhumanadenovirusinfectionanddevelopmentofeffective
antiviraltreatmentoptionsforthishighlyvulnerableagegroupareurgentlyneeded.
3.3. EpidemiologicalandclinicalcharacteristicsofenterovirusD68(EV-D68)infectionamongchildrenagedlessthanfiveyearsinthePhilippines
MarikoSaito-Obata,TohokuUniversityGraduateSchoolofMedicine,Miyagi,Japan
Human enterovirus D68 (EV-D68), a member of the Picornaviridae family, was first isolated from pediatric patients hospitalized with lower
respiratoryinfectioninCaliforniain1962(Schiebleetal.,1967).Before2000,EV-D68wasararelyreportedviruslinkedwithrespiratorydisease.
However,ithasspreadworldwideinthe21stcentury(Obersteetal.,2004;Tokarzetal.,2012).Mostrecently,thereportednumberofEV-D68cases
in acute respiratory infections (ARI) significantly increased (Biggs et al., 2017). To explore possible reasons for the recent increase, the epide-
miologicalandclinicalcharacteristicsofEV-D68inchildren(<5-year-old)wereanalyzed.Ahospital-basedstudyonchildrenwithclinicaldiagnosis
ofseverepneumoniabasedonIntegratedManagementofChildhoodIllness(IMCI)criteriawasperformedinseveralsitesinthePhilippinesfrom
2008to2015.AprospectivecohortstudyonchildrenwithsymptomsofARIwascarriedoutinBiliranIslandfrom2014to2016.Nasopharyngeal
swabs (NPS) were taken from children and respiratory viruses in the samples, including influenza virus, rhinovirus, respiratory syncytial virus,
adenovirusandEV-D68weredetectedbyRT-PCR.ToconfirmdetectionofeachvirusandtodeterminegenogroupofEV-D68,DNAsequencingwas
conducted.
Amongthetotalof5438NPSsamplescollectedfromthehospitalizedcases,59samples(1.1%)wereconfirmedEV-D68positive,whileamongthe
6608NPSsamplescollectedforthecohortstudy,60(0.9%)wereEV-D68positive.Casefatalityratewas8.5%inthehospitalizedEV-D68positive
cases,whereasthatinEV-D68thehospitalizednegativecaseswas3.6%(P=0.06).Phylogeneticanalysis,showedthesePhilippinestrainsbelonged
tolineage2(L2)and3(L3).About57.6%,20.3%,and22.0%ofthehospitalizedEV-D68positivecaseswereL2,L3andundetermined,respectivelty.
ThereisnosignificantdifferenceinthecasefatalityratebetweenL2(5.9%)andL3(16.7%)(P=0.2),andtheproportionsofveryseverepneumonia
(61.3%vs50%,P=0.3).Similarly,about78.3%,16.7%,and5.0%oftheEV-D68positivecohortcaseswereL2,L3andundetermined,respectivelty.
Interestingly,theproportionofcasesdiagnosedaspneumonia/severepneumonia/veryseverepneumoniainL2(57%)wassignificantlyhigherthan
thatinL3(20%)(P=0.048).TheresultsfromthisstudysuggestthatthoughthepositiveratesofEV-D68arelowinbothhospitalizedchildrenwith
pneumoniaandcohortchildrencaseswithARIinthePhilippines,EV-D68isassociatedwithmoreseverepneumonia.ThePhilippinestrainsofEV-
D68belongedtoL2andL3,whileL2isthedominantgenogroupandisassociatedwithmoreseverediseaseincohortchildren,confirmingthatEV-
D68isanimportantpathogenforARIanditsL2andL3possessdifferentepidemiologicalandclinicalcharacteristics.
3.4. DetectionofinfluenzaA(H1N1)pdm09virusesexhibitingenhancedcross-resistancetooseltamivirandperamivirinJapan
EmiTakashita,NationalInstituteofInfectiousDiseases,Tokyo,Japan
ContinuousevolutionintheinfluenzaHAandNAglycoproteinscanresultinreducedefficacyofantiviraldrugsandvaccines.Forexample,a
singleH275YsubstitutionintheNAoftheA(H1N1)pdm09virusconfersresistancetotheNAIs,oseltamivirandperamivir.Thefirstwidespread
community cluster of the H275Y mutant A(H1N1)pdm09 virus was identified in Newcastle, Australia in 2011 (Hurt et al., 2012). During the
2013–2014 influenza season inJapan, a large community cluster ofinfluenza A(H1N1)pdm09 virus exhibited cross-resistance to the NAIs,osel-
tamivirandperamivir(Takashitaetal.,2014,2015).Inthe2015–2016influenzaseason,surveillanceofNAI-resistantvirusesthroughoutJapanwas
conducted. A fluorescent NA inhibition assay was used to determine the susceptibilities of viruses to oseltamivir, peramivir, and other NAIs,
zanamivirandlaninamivir,accordingtotheWHOcriteria,whicharebasedonthefoldchangeofIC valuescomparedtothemedianIC valuesof
50 50
thesamesubtype/lineage(WHO,2012).
Afterscreening2584A(H1N1)pdm09viruses,50(1.9%)viruseswerefoundtopossessanH275YsubstitutionintheNAprotein.TwoH275Y
mutantviruseshadanadditionalG147RorI223KsubstitutionintheNAprotein.ComparedwiththesingleH275Ymutantviruses,thedualH275Y/
G147RandH275Y/I223Kmutantvirusesexhibitedenhancedcross-resistancetooseltamivirandperamivirandreducedsusceptibilitytozanamivir
andlaninamivir.ThedualH275Y/I223Kmutantvirusexhibitedreducedinvitroreplicationcapacity,whilethedualH275Y/G147Rmutantvirus
retainedtheabilitytogrow.TheseresultssuggestthatthedualH275Y/G147RandH275Y/I223Ksubstitutionsexhibitedsynergisticeffectscom-
paredwiththoseforthesingleH275Ychange.BecausethedualH275Y/G147Rmutantvirusretainedviralfitness,ithasthepotentialtospread
amonghumans.
3.5. Clinicalandvirologicaloutcomesuponemergenceofoseltamivir-resistantinfluenzaAvirusesintreatedindividuals:theIRISstudy
RueshandraRoosenhoff,ErasmusMedicalCenter,Rotterdam,TheNetherlands
ToassistintheearlydetectionofIAVsresistanttoantiviralsandtomonitortheclinicalandvirologicaloutcomeofadultsandchildreninfected
with IAVs according to subtype and susceptibility, the Influenza Resistance Information Study (IRIS; NCT00884117) has been conducted in the
UnitedStates,Australia,France,Germany,HongKong,Norway,andNetherlandsbetween2009and2016(Roche,2016).Overa7-yearperiod,2213
oseltamivir-treated,IAV-infectedpatientswithfollow-upwereanalyzedfortreatment-associatedemergentceofresistance.QuantitativeIAVRT-PCR
wasperformedonnasalandthroatswabstakenatday1(forbaseline)andondays3,6and10,respectively.Forgenotypingandphenotypingofthe
virus,mutationspecificRT-PCR(275Y,119V,292K)andnextgenerationsequencingonoriginalswabswereperformed.SangersequencingandNA
inhibitionanalysiswereconductedbyNA-STARassayonculturedmaterial.Resistancemutationsweredetectedin57(2.6%)ofoseltamivir-treated
patients,including39infectedbyA(H1N1)pdm09withtheH275Ysubstitutionand18infectedbyA(H3N2)strainswiththeR292Ksubstitution.The
resistancemutationswerefirstdetectedonday3,6and10in27%,68%and5%oftheoseltamivir-treatedpatients,respectively.Atthenextvisit,the
resistantmutantwasclearedin73%ofthesepatients.Theresistantvirusesisolatedfrom27patientswerelessthan10%oftheviruspopulation,as
121
MeetingReport Antiviral Research 149 (2018) 118–142
detectedbymutation-specificRT-PCR,buttheywerenotdetectedbytheNA-STARassay.However,for74%ofthepatientsinwhomresistantmutant
strainswerethemajorityspecies,anoseltamivirresistantphenotypewasconfirmedbytheNA-STARassay.ForA(H1N1)pdm09strains,medianviral
RNA clearance was 11.9 and 8.9 days for resistant and wild-type cases, respectively (P < 0.0001), while there is no signficant difference in
clearanceofA(H3N2)strains.Insummary,oseltamivir-resistantmutantsofIAVsweredetectedin2.6%ofoseltamivir-treatedpatients.Although
thesemutationsarenotassociatedwithothermajorsubstitutionsinHAandNAproteinsthatpotentiallyaidviralfitness,theyareassociatedwith
delayedclearanceofA(H1N1)pdm09,butnotwiththatofA(H3N2)virus.
InanotherIRISsubstudy,viralsheddingandsusceptibilitytooseltamivirinhospitalizedimmunocompromisedpatientsinfectedwithIAVswas
monitored.Byday9mostpatientshadnotclearedthevirus.Fourof24patients(17%)shedresistantvirus(Fraaijetal.,2015).Correlationbetween
symptomseverityandlevelofcompromisecouldnotbedetermined.
3.6. UpdateandconsolidationofWHOstandardguidelinefortheclinicalmanagementofsevereinfluenzainfections
PaulaLister,GreatOrmondStreetHospital,London,UK
Influenza viruses, particularly the zoonotic viruses, such as avian influenza viruses of A(H5N1), A(H7N9), and A(H9N2) subtypes and swine
influenza viruses of A(H1N1) and A(H3N2) subtypes, pose an enormous threat to global public health. In March 2013, the first case of human
infection with avian-origin influenza A(H7N9) virus was reported in China (Gao et al., 2013). So far, there have been five A(H7N9) influenza
epidemicwavesinChina.ThefifthwavebeginninginOctober2016revealedthesteepestincreaseinthenumberofhumancases.Additionallythe
emergenceofhighlypathogenicA(H7N9)strains(Suetal.,2017)hasnowbeenreported.
InDecember2009,theWHOissuedupdatedguidelinesforthepreventionofA(H1N1)pdm09infectioninhealthcaresettings(Choretal.,2012).
In 2010, the current WHO guidelines for the clinical management of A(H1N1)pdm09 and other influenza viruses were published, which have
contributedtotheChineseNationalguidanceforinfluenzaA(H7N9).TheWHOstandardguidelinefortheclinicalmanagementofsevereinfluenza
willbeupdatedandconsolidatedtoincludethenewevidencethathasbeenpublishedinrecentyears.ThisupdatedandconsolidatedWHOstandard
guideline willbedeveloped bytheGuidelineSteeringCommittee (GSC)andtheGuideline DevelopmentGroup(GDG),aglobally representative
groupwithbroadexpertiseincludinginfectiousdisease,virology,paediatricsandpublichealth.Importantareaswithnewevidenceforconsideration
include:1)diagnostics(includingpointofcare),2)treatmentwithNAIs,includingthenewerlicencedNAIs,and3)thesupportivecareofseverelyor
critically ill patients with hypoxia and/or shock. Systematic reviews will be commissioned to inform the guideline. The GDG will formulate re-
commendationsbasedontheevidencequalityasassessedusingtheGRADEapproach,whiletheGSCwillensurethattheguidelinemustmeetthe
breadthoftheWHOpublichealthagenda,includingsubpopulationsvulnerabletoseverediseases.TheUpdateandConsolidationofWHOStandard
GuidelinefortheClinicalManagementofSevereInfluenzaInfectionsisexpectedtobepublishedearlyin2018.
4. AvianA(H7N9)influenza
4.1. InfectionpreventionandcontrolforpatientswithavianinfluenzaA(H7N9)virusinfection
YinzhongShen,ShanghaiFudanUniversity,China
InfluenzaA(H7N9)virushasbeendetectedandisolatedinbirds,theirsecretionsandinLPMenvironments.ClosureofLPMshasbeeneffectivein
reducingthehumanrisksofA(H7N9)infection(Yuetal.,2014b).MostofthehumancasesofA(H7N9)infectionaresporadic,buttherehavebeen
severalfamilyclustersinwhichlimited,non-sustainedhuman-to-humanA(H7N9)virustransmissioncannotberuledout(Lietal.,2014).Limited
humantohumantransmissioninthehospitalsettings,togetherwithriskfactorssuchasanovercrowdedwardenvironmentandperformanceof
aerosol-generating procedures, has been reported (Chen et al., 2016; Fang et al., 2015). When caring for patients with ARI, the WHO infection
prevention and control (IPC) guidelines for ARI patient care that are applicable to A(H7N9) patients include early recognition and isolation of
patients, application of routine IPC precautions (Standard Precautions) for all patients, additional precautions in selected patients (e.g. airborne
precautions for high risk aerosol-generating procedures), and other IPC strategies in health-care facilities such as early recognition and source
control,administrativecontrols,environmentalandengineeringcontrols,andpersonalprotectiveequipment(WHO,2014).
4.2. EpidemiologyofhumaninfectionswithA(H7N9)virusandcontrolmeasuresinmainlandChina
LeiZhou,ChinaCDC,Beijing,China
Between2013andJune2017,1503casesofhumaninfectionwithinfluenzaA(H7N9)virushavebeenreported,withmorethan500fatalities.An
earlier start and a steep increase in the number of human cases of A(H7N9) virus infection was observed during the fifth epidemic in China in
2016–2017 (Zhou etal.,2017a). Most human casesoccurred inEasternandSouthernChinaintheearlierepidemics. However,six provincesin
CentralandWesternChinawithoutpreviouscases,reportedhumaninfectionsinthefifthepidemic,indicatinggeographicexpansionofA(H7N9)
cases. In comparison with the earlier epidemics, the epidemiology characteristics such as sex and age of patients infected with A(H7N9) virus
remainedunchanged,buttheproportionofruralresidentsamongconfirmedcasesincreasedinthefifthwave.Severityremainedhighinthefifth
epidemic:90%ofcaseswerediagnosedassevere,and79%ofcaseswereadmittedintoanintensivecareunit.Most(90%)casesreportedexposures
topoultry,including75%thathadvisitedanLPMbeforeillnessonsetorhadcontactwithpoultrypurchasedfromanLPM.Since2013,37clusters
(comprising 78 cases), of at least 2 epidemiologically-linked confirmed cases have been identified, including 11 clusters reported in the fifth
epidemic.Therewerenochangesinthesizeornumberofclustersperepidemicandtherewasnoevidenceofsustainedhuman-to-humantrans-
mission.Whilemosthumancasesconfirmedsince2013werecausedbylowpathogenicavianinfluenza(LPAI)A(H7N9)virusinfection,25casesof
HPAIA(H7N9)virusinfectionhavebeenidentifiedinthreeprovincesinsouthernChinaduringthefifthepidemic.Preliminaryanalysisindicated
thatHPAIA(H7N9)virus-infectedpatientsweremorelikelytoliveinruralareas,haveexposuretosickordeadpoultry,andadmittedtohospitals
earlierthanLPAIA(H7N9)cases.ExtensiveeffortsareneededtopreventandcontrolthespreadofLPAIandHPAIA(H7N9)virusesamongpoultry,
includinginruralareas(Zhouetal.,2017b).
122
MeetingReport Antiviral Research 149 (2018) 118–142
4.3. Virologicalupdate
YuelongShu,ChinaCDC,Beijing,China
TheYangtzeRiverDeltaregion,locatedineasternChina,iswell-recognizedastheoriginalsourceforA(H7N9)influenzaoutbreaks.Basedonthe
evolutionary analysis of A(H7N9) viruses from the first 3 epidemic waves, the PearlRiver Delta region has been identified asanother A(H7N9)
outbreaksource.A(H7N9)virusesarerepeatedlyintroducedfromthesetwosourcestotheotherareasandthepersistentcirculationofA(H7N9)
virusesoccursinpoultry,causingcontinuousepidemicwaves.TheinternalgenescontinuetoreassortwiththeA(H9N2)viruses,andboththeHA
andNAproteinsareevolving.Morethan93genotypeshavebeenidentified,withmorethan80ofthesebeingtransient.TheAnH1genotype,which
waspredominantduringthefirstepidemicwave,wasreplacedbyJS537,JS18828,andAnH1887genotypesduringthesecondandthirdepidemic
waves(Wangetal.,2016a)).Inlate2016andbeginningof2017,threepatientswithsevereclinicalsymptomswereconfirmedtobeinfectedwith
HPAIA(H7N9)viruses.ThevirusesbelongedtotheYangtzeRiverDeltalineage.Fouraminoacidsinserted(Lys-Arg-Thr-Ala)attheHAcleavagesite
enabled the A(H7N9) HPAI virus to display trypsin-independent infectivity (Zhu et al., 2017). Additionally, the HPAI viruses have acquired the
L226QsubstitutionintheHA,althoughmaintainingdualreceptor-bindingpreference.TheHPAIHAantigenicityisdistinctfromtheLPAIA(H7N9)
viruses. All viruses have the S31N substitution in their M2 protein, conferring amantadine resistance. Among 314 LPAI viruses tested for NAI
susceptibility, 18/314 had decreased sensitivity, one with I222R, two with A246T and 15 with the R292K substitutions, the latter conferring a
multidrugresistancephenotype.AmongHPAIvirusestested,4/21alsohadreducedsensitivity,withthreeofthosewiththeR292Ksubstitution(Ke
etal.,2017).All292Kisolatesarosepost-treatment.Therefore,surveillanceofthevirus,especiallyantiviralsurveillance,isanessentialcomponent
ofpandemicpreparedness.
4.4. Antiviraltreatmentandresistance
XiaonanZhangonbehalfofJunwenHu,ShanghaiFudanUniversity,China
The emergence of NAI-resistant variants of A(H7N9) viruses with an R292K NA substitution poses a therapeutic challenge. In a study of 14
patientswithA(H7N9)infectioncomplicatedbypneumonia,NAItreatmentwasassociatedwithareductionofviralloadinthroatswabspecimensin
11survivingpatients.However,3patientswithpersistentlyhighviralloadsinthethroat,despiteantiviraltherapy,becamedependentonextra-
corporealmembraneoxygenation.AnR292KNAsubstitutionwasidentifiedintwoofthesepatients,whohadalsoreceivedsystemiccorticosteroid
treatment. In one of them, wild-type sequence R292 was noted 2 days after commencement of NAI treatment, and the resistant mutant K292
dominated 9 days after commencement of treatment (Hu et al., 2013). Using limited serial passage in the presence of oseltamivir, and plaque
purification,anR292KvariantoftheAnhui1lineagewasisolatedfromapatientwithclinicalevidenceofresistancetooseltamivir.Invitroandcell-
basedassaysconfirmedahighlevelofresistanceofA(H7N9)viruscarryingtheR292Ksubstitutiontooseltamivircarboxylateandamoderatelevel
ofresistancetozanamivirandperamivir.Non-NAIantivirals,suchasT-705,ribavirinandNT-300,efficientlyinhibitedboththevariantandthewild-
typevirusesincell-basedassays.AcombinationofNAIsandnon-NAIsdidnotexhibitamarkedsynergisticeffectagainsttheR292Kvariantincell
culture.However,thecombinationoftwonon-NAIs(T-705andribavirin)exhibitedsynergismagainstthemutantvirus.Inexperimentallyinfected
mice,theR292Kvariantshoweddelayedonsetofsymptoms,areducedviralloadandattenuatedlethalitycomparedwiththewild-type.Thestudy
suggestednon-NAIsshouldbetestedclinicallyforA(H7N9)patientswithasustainedhighviralload.Possibledrugcombinationregimens,suchasT-
705plusribavirin,shouldbefurthertestedinanimalmodels.Areal-timeRT-PCRandsinglenucleotidepolymorphismprobeshavebeendeveloped
to differentiate this mutant strain in mixed virus populations in human specimens (Wang et al., 2014b). Screening of 18 patients undergoing
oseltamivirtherapyidentifiedviruseswithmixedR/Ksequence,notpreviouslydetected.
5. RVIdiagnosisandtreatment
5.1. Advancesinrespiratoryvirusinfectionmoleculardiagnostics
Yi-WeiTang,MemorialSloanKetteringCancerCenter,NewYork,USA
Clinical manifestations of respiratory virus infections are usually non-specific, with significant overlap between viral, bacterial, and non-in-
fectious causes. New technologies, with improved multiplexing capabilities, has allowed detection anddifferentiation ofmultiple virusesfrom a
single respiratory sample. In order to be clinically useful, clinicians want rapid turn around with multiple pathogens detected. For a clinical
microbiologylaboratoryhandlinglowtomediumspecimenvolumes,theseplatformsarepreferredastheyallowasimpleworkflowthatcanbeused
withminimaltraining,andaffordarapidturnaroundtime.However,theseplatformsarenotcapableoflargevolumesoftesting.Batchedtesting
highthroughputplatformsareusefulforunexpectedincreasesintestingvolumesuchasnosocomialoutbreaks,peakinfluenzaseasons,andduring
pandemics.Onesystemwillnotworkforallsituations.Laboratoriansandcliniciansshouldknowthelimitationsofalltestplatformsavailable.
5.2. Asimpletool-CLAPtoassesstheseverityofinfluenzaA(H7N9)viralpneumonia
YemingWang,XuanWuHospitalCapitalMedicalUniversity,Beijing,China
InfluenzaA(H7N9)virushasmortalityratesofupto50%.AclinicalseverityassessmenttoolisneededtohelptriagepatientswithA(H7N9)
infections.Currentseverityassessmenttoolshavenotbeentestedinthispopulation.Thegoalofthisstudywastodevelopanewclinicalseverity
tool,andcomparetocurrentlyavailabletoolssuchasPSI(PneumoniaSeverityIndex)(Fineetal.,1995),SMARTCOP(Charlesetal.,2008)(systolic
bloodpressure,multilobarchestradiographyinvolvement,albuminlevel,respiratoryrate,tachycardia,confusion,oxygenation,andarterialpH),
andCURB-65 (Limetal., 2003) (confusion, ureanitrogen, respiratory rate,bloodpressure, 65 years ofage andolder). Datawascollected from
patientswhowerehospitalizedwithinfluenzaA(H7N9)infectioninChina.Aderivationcohortwasconstructedfromtheclinicaldataof613patients
hospitalized between April2013 andMarch2015. Ofthese,285 patientshadcomplete data. The 30-day mortalityofthederivationcohort was
26.3%.Amultivariatelogisticregressionwasperformedtoidentifyclinicalfeaturesatadmissiontohospitalthatwereassociatedwithmortality
within30days.Theseresultswereconvertedintoasimplepoint-basedseveritytoolwhichwasbasedoncreatininelevel,lymphocytecount,PaO2/
FiO2,andage.The30-daymortalityofthevalidationcohortwas47.4%.Riskfactorsassociatedwith30-daymortalitywerecreatinine>133μmol/L
(1point),lymphocytecount < 0.3×109/L(1point),age > 60(1point)or80years(2points),andPaO2/FiO2 < 100(2points)or200mmHg
123
MeetingReport Antiviral Research 149 (2018) 118–142
(1point).ThescoringsystemiscalledCLAP.Afterderivationofthescoringsystem,avalidationcohortwascompiledwithclinicaldatafrom171
patientshospitalizedbetweenOctober2016andMarch2017.SensitivitiesandspecificityofCLAPonadmissionidentifyingthe30-daymortality
were90.79%and45.45%,respectively.ThehighestAUROCswerefortheCLAPscore(0.77;95%CI,0.72–0.82)andthePSIscore(0.73;95%CI,
0.68–0.78)comparedwith0.62(95%CI,0.56–0.68)forSMART-COP(P < 0.001,comparedwithCLAP)and0.59(95%CI,0.55–0.65)forCURB-65
(P < 0.001,comparedwithCLAP).CLAPisasimplescoringtoolthatmyhaveutilityinpredictingtheoutcomeofpatientsinfectedwithinfluenza
A(H7N9)viralpneumonia.
5.3. InvestigationofantibodydynamicsintherandomizedstudywithJapanesepediatricpatientswithinfluenzaAvirusinfectionaftertreatmentoffour
neuraminidaseinhibitors
NobuoHirotsu,HirostuClinic,Kawasaki,Japan
Itisnotknownifantiviraltreatmentmayaffectthedevelopmentoftheadaptiveimmuneresponseafterinfluenzainfections.Inastudypre-
viouslyreportedatOptionsIXfortheControlofInfluenza,133participantsbetween4and12yearsofagethatpresentedwithin48hoursofillness
onsetwere randomlyallocated to beadministeredoneoffourNAIs: oraloseltamivir, inhaled zanamivir, intravenous peramivir,orinhaled lani-
namivir.Theprimaryendpointwastimetoundetectable virustiter.Peramivirshowedashortertimetoviralclearancewhencomparedtoosel-
tamivir(adjustedP=0.035).Thisanalysisexaminediftheadaptiveimmuneresponse,asmeasuredbyhemagglutinin-inhibitionassay(HAI),was
differentamongtreatmentgroups.Approximately80%oftheenrolledpatientswereinfectedwithinfluenzaA(H3N2)virus,and20%withinfluenza
A(H1N1)pdm09.Antibodylevelswereevaluatedatthreetimepoints:baseline,day3–4,andday14 ± 3.Therewerenosignificantdifferencesin
HAItiter increase(ratioofthebaselineto theday 14visit) betweentreatments. Priorvaccination,priorinfluenzaA(H3N2) infection, andprior
familyhistoryofinfluenzaillnessallwereassociatedwithhigherpre-treatmentantibodylevels.Higherantibodyincreasesfromday0today14
correlatedwithfasterresolutionofviralshedding.
5.4. Arandomizedcontrolledtrialonadjunctivemacrolidetreatmentinadultshospitalizedwithinfluenza
NelsonLee,TheChineseUniversityofHongKong,HongKongSAR,China
Hypercytokinemiaisseeninsevereinfluenzaandassociatedwithpooroutcomes(Liuetal.,2016).Macrolideshaveanti-inflammatoryprop-
erties,andmayattenuatecytokinelevelsinacuteinfluenza(KanohandRubin,2010).Thiswasarandomized,open-label,multicentertrialamong
adultshospitalizedforlaboratory-confirmedinfluenza.Adults≥18yearsofagewithlowerrespiratorytractinfectionthatpresentedwithin4days
onsetofillnesswereeligibleforthestudy.Subjectswerenoteligibleiftheyweretakingcorticosteroids,orhadbaselineQTcprolongationonEKG.
Participantswererandomizedina1:1ratiotoreceiveoseltamivirandazithromycin(500mg/day),versusoseltamiviralonefor5days.Theprimary
outcome was the change in plasma cytokine/chemokine concentration over time (days 0–10). Fifty patients were randomized to the study. The
treatment arms had comparable baseline characteristics: age was 57 ± 18 years; 70% had influenza A(H3N2), and viral loads were similar.
Macrolidetreatmentwasassociatedwithlowerpro-inflammatorycytokinesIL-6(reductionfrombaseline−83.4%vs−59.5%,P=0.016),CXCL8/
IL-8(80.5%vs−58.0%,P=0.056),IL-17(−74.0%vs−34.3%,P=0.015),CXCL9/MIG(−71.3%vs−56.0%,P=0.043).However,theduration
offever,durationofsymptoms,andviralsheddingwerenotdifferentbetweenthetwotreatmentarms.
5.5. BroadspectruminvitroandinvivoactivityofRO-7,anovelinhibitoroftheinfluenzavirusPAendonuclease
JeremyJones,St.JudeChildren'sResearchHospital,Memphis,TN,USA
Theinfluenzavirusacidicpolymerase(PA)isapromisingantiviraltargetbecauseofitsessentialroleinvirustranscription.RO-7isanewPA
protein endonuclease inhibitor (Jones et al., 2017). RO-7 was tested against 36 influenza A and B viruses in MDCK and differentiated human
bronchialepithelialcells.RO-7inhibitedreplicationofmultiplestrainsofinfluenzaA(H1N1,H3N2,H5N1,H7N9,H9N2)andBvirusesaswellas
NAI-resistantvariants(meanEC 2.9–105.3nM).
50
AlethalBALB/cmousemodelwasestablishedusing5MLD ofA/California/04/2009A(H1N1)pdm09(1.1×10350%tissuecultureinfectious
50
doses[TCID ])orB/Brisbane/60/2008(2.5×105TCID )virus.ThemiceweretreatedwithRO-7at6,15or30mg/kg/daytwicedailyfor5days
50 50
starting4hoursbeforeor24or48hoursaftervirusinoculation.AlldoselevelsofRO-7exhibitedreducedmorbidity,increasedsurvival(60–100%),
reducedlungvirusload,anddecreasedlungpathologycomparedtountreatedcontrols.NoRO-7resistancewasobservedinvirusesisolatedfrom
drug-treatedmouselungs.Viruswith60-foldreducedsensitivitywasselectedafter16passagesinMDCKsunderincreasingRO-7concentrations,
withanI38TsubstitutioninthePAendonucleasedomain.However,99%ofcirculatingvirusesdonothavethischange.
5.6. Thetopaztrial:aphaseIIBstudyofpimodivir(JNJ-63623872orJNJ-872;formerlyVX-787)asmonotherapyorincombinationwithoseltamivirinthe
treatmentofacuteuncomplicatedseasonalinfluenza
LorantLeopold,Janssen,Titusville,NewJersey,USA
PimodivirisaPB2subunitinhibitoroftheinfluenzaApolymerase(Fuetal.,2016).ThiswasaPhaseIIstudyevaluatingthesafetyandpotential
efficacyofpimodivir.Adults 18–65 yearsofagewith acuteuncomplicated influenzaAvirusinfection thatpresentedwithlessthan48 hoursof
symptoms were eligible for the study. Participants were randomized 1:1:1:1 to receive placebo, pimodivir 300 mg, pimodivir 600 mg, or the
combination pimodivir 600 mg/oseltamivir 75 mg for 5 days. 967 participants were screened, 293 randomized, and 223 used for the primary
analysis.Thedemographicswerebalancedacrosstreatmentarms,with84%caucasians,51%femalesandamedianageof41years.Whencompared
toplacebo,600mgofpimodivirresultedinagreaterdecreaseinqRT-PCRareaunderthecurve(AUC)forviralloadfromday1–8,comparedto300
mg[-4.5(−8.0;−1.0);0.012vs−3.6(−7.1;−0.1);0.044log copies/ml].Thecombinationofpimodivirandoseltamivirdemonstratedfurther
10
reduction when compared to pimodivir 600 mg (−4.1 log copies/mL, −7.4 to −0.7, P = 0.017). There was no change in median time to
10
resolutionofsymptoms:pimodivir300mg,99.0hours(71.5–150.6),pimodivir600mg,85.7hours(55.3–114.9),pimodivir+oseltamivir,70.4
hours(61.8–82.5),andplaceboalone,86.4hours(68.7–117.3).Themostcommonadverseeventwasdiarrhea,typicallymild,andsimilaracross
treatmentarms.Althoughpimodivirshowedastatisticallysignificantdecreaseinviralareaunderthecurve,thisdifferencewasnotassociatedwith
improvedclinicalbenefit.Thedosageof600mgofpimodivirhasbeenselectedforPhaseIIIstudies.
124
MeetingReport Antiviral Research 149 (2018) 118–142
5.7. IRC003:arandomizedstudyofcombinationantiviralsforthetreatmentofinfluenza
JohnBeigel,LeidosBiomedicalResearch,SupporttoNIAID,Bethesda,MD,USA
Preclinical data suggests that a combination of anti-influenza antivirals could be more effective than oseltamivir alone in the treatment of
influenza.Thiswasarandomized,blinded,multicenterPhaseIItrialintheUnitedStates,Thailand,Mexico,ArgentinaandAustralia.Participants
thatwereeither65yearsofageorolder,hadachronicmedicalcondition,and/orwereobesewithconfirmedinfluenzaAorBwereeligibleforthe
study.Enrolledsubjectswererandomlyassignedtoreceiveeitherthecombinationofoseltamivir,amantadine,andribavirinoroseltamiviralonefor
5days,andwerefollowedfor28days.TheprimaryendpointwasthepercentageofparticipantswithvirusdetectablebyPCRinanasopharyngeal
swabatday3.881participantswereenrolled,and633wererandomized.SevenparticipantswereexcludedfromtheITTpopulation:3werenot
randomizedappropriately,and4withdrewbeforetakinganystudymedication.Theprimaryanalysisincluded394participants,excluding47inthe
pilotphase,172withoutinfluenzaconfirmedinthecentrallaboratory,and13withoutanendpointsample.80of200(40.0%)participantsinthe
combinationarmhadvirusdetectableatday3comparedto97of194(50.0%)(95%C.I.0.2–19.8%,P=0.046)inthecontrolarm.
Therewasnobenefitinclinicaloutcomesacrossmultipleparameters:thedurationofclinicalsymptoms(4.5daysinthecombinationarmvs4.0
daysinoseltamivirmonotherapy,P=0.44),durationoffever(0vs1day,P=0.69),timetofeelingasgoodasbeforetheinfluenzaillness(7.5vs
6.5days,P=0.0033),nortimetoreturnofpre-illnessphysicalfunctionusingthephysicaldomainoftheSF-36(7.0vs6days,P=0.06).Themost
commonadverseeventswerenausea[65(12%)vs63(11%)],vomiting[56(10%)vs64(11%)]anddiarrhea[39(7%)vs23(4%)],andoccurredin
similarproportionsinbotharms.Althoughoseltamivir,amantadine,andribavirinshowedastatisticallysignificantdecreaseinviralsheddingatday
3relativetooseltamivirmonotherapy,thisdifferencewasnotassociatedwithclinicalbenefit.
6. Keynote:burdenofrespiratoryvirusdiseasesinChina
HongjieYu,SchoolofPublicHealth,FudanUniversity,China.
Chinaisageographically,economically,andclimatologicallydiversecountrywithapopulationofapproximately1.37billion.Thesefactors,in
part,contributetowardsitssubstantialinfluenzamortalityburden,estimatedat11–18excessdeathsper100,000inthesouthernandnortherncities
intheinter-pandemicseasons(Fengetal.,2012).AlthoughseasonalinfluenzavaccinationwasintroducedinChinain1998,itisnotincludedinthe
nationalimmunizationprogram.Theinfluenzavaccinecoverageisstillrelativelow:2009/2010–8.5%,2010/2011–9.5%,2011/2012–4.3%,mainly
intheelderlyinwealthiercities.Additionally,substantialvaccinationratediversityisobservedamonglow-andhigh-incomecitiesandprovinces.
Onthebasisofmultiyearlaboratory-confirmedinfluenzasurveillancedatarepresentativeofalargemajorityoftheChinesepopulation(2005–2011),
threeepidemiologicalregionswereidentifiedforinfluenzaAvirusinfection:northernprovinces(latitude≥33°N)experiencewinterepidemics,
southernprovinces(latitude < 27°N)experiencepeakactivityinspring,whileprovincesatintermediatelatitudesexperiencesemi-annualepidemic
cycles(Yuetal.,2013).Therefore,itisoptimalforNorthernChinatofollowthetimingofvaccinationtypicallyrecommendedfortheNorthern
Hemisphere,withannualcampaignsstartinginOctober.Incontrast,mostofsouthernChineseprovinceshavetoaccommodateinfluenzaactivity
peakinginApril–June,andhencevaccinationwouldbebestinitiatedinFebruary–Marchofeachyear,broadlycoincidingwiththerecommended
timingofvaccinationfortheSouthernHemisphere.
The National Influenza Surveillance Network was launched in China in 2000. Before the 2009 influenza pandemic, only southern Chinese
provincesandthreenorthernprovinces(includingGansu,LiaoningandTianjin)conductedfull-yearinfluenzasurveillance,althoughothernorthern
provinces conducted half-year surveillance. Now this network includes 411 provincial- and prefecture-level Centers for Disease Control and
Prevention(CDCs)and556sentinelhospitalssituatedin31provinces.Currently,allprovincesaredoingyear-roundinfluenzasurveillance.Sentinel
hospitalsreportthenumbersoftotaloutpatientvisitsandthenumbersofvisitsbyoutpatientswithILIandagegroup.Aretrospectivetelephone
surveyestimatedthecostoftreatmentforout-patientsforinfluenzawas$155USDand>$1500forin-patients(Yangetal.,2015).Thenational
sentinelhospital-basedinfluenzasurveillancenetworkandsurveillanceforSARIincentralChinashowedthatoutpatients,hospitalization,mortality
andeconomicburdensassociatedwithinfluenzaaresubstantialinChina.Significantvariationswereobservedininfluenza-associatedILIburdenand
SARIhospitalizationsbyprovinces,age,andinfluenzavirustype.Inonesurveyofapproximately80millionpatientspresentingatsentinelhospitals
3.1%hadILIandofthosetestedforinfluenza,12.3%werepositive.Surveillanceamong4hospitalsinJingzhoufrom2010-2012showedthatof
16,208 SARIcases tested, 2057 (13%) had confirmed influenza, including 1427 (69%) aged<5 years (Yu et al., 2014a). Marked differences in
seasonalityofinfluenzaAandBvirusesweredetermined,withmostofChinaexperiencingannualinfluenzaBactivityinwinter.Activesurveillance
forhospitalizedpatientswithacutelowerrespiratoryinfectionsrevealedthespectrumofviralagentsin24provincesofChinaduring2009–2013:
influenzain1869patients(6.6%),RSVin2795patients(9.9%),PIVin1366patients(4.8%),adenovirusin957patients(3.4%),bocavirusin551
patients(1.9%),humanmetapneumovirusin424patients(1.5%)andhCoVin393patients(1.4%)(Fengetal.,2014).
7. RVIimpactandcommunityacquiredpneumonia(CAP)
7.1. NewclinicalguidelinesforCAPinChina
BinCaoforJiemingQu,ShanghaiRuijinHospital,Shanghai,China
TheAssemblyofInfectiousDiseasesoftheChineseThoracicSocietyhasrevisedtheClinicalPracticeGuidelineforCAPandpublishedanupdated
ChineseversioninApril2016(QuandCao,2016).Thisversionisbasedonnewevidencethathasemergedintherecentdecadeontheetiological
profileofCAPinChina,advancesinlaboratorydiagnosis,neweranti-infectivetherapies,andaccessibilitytoeffectivevaccines(Torresetal.,2016).
ThemaincontentsoftheGuidelineinclude:definitionanddiagnosisofCAP,assessmentofCAPseverity,criteriaforhospitaladmission,etiological
diagnosis,anti-infectivetherapies,adjunctivetherapies,assessmentafterinitialtherapyandthecriteriafordischarge,unusualtypesofCAP,and
prophylaxis.Therecommendationsweregradedbasedonthestrengthoftheevidenceaccordingtointernationalstandards.Streptococcuspneumoniae
and Mycoplasma pneumonia are the commonest bacterial pathogens, which have distinctive resistance patterns (penicillins, macrolides); gram-
negativepathogens(e.g.Klebsiellapneumonia,E.coli)aremorefrequentlyfoundinthespecialpopulationssuchastheelderly;respiratoryviruses
constitute15–35%ofcases,withinfluenzabeingthemostimportantpathogen.Community-acquiredMRSAinfectionsremainrare.TheCURB-65
score is recommended as a tool to assist decision on hospitalization of Chinese patients. The use of culture-based, antigen-based and molecular
assays,aswellasbiochemicalmarkers(e.g.procalcitonin)fordiagnosisisdiscussed;empiricalantibacterialsandantiviralsarerecommendedbased
125
MeetingReport Antiviral Research 149 (2018) 118–142
on the epidemiological data, clinical scenario and resistance profiles. NAIs are recommended for influenza pneumonia. Influenza vaccines and
pneumococcalvaccines(polysaccharide,conjugated)arerecommendedforprevention.AnEnglishversionofthispracticeguidelineisunderpre-
paration.
7.2. Contactpatternsofhealthcareworkersandtransmissionofinfectiousdiseases
LiliJiang,NationalUniversityofSingapore,Singapore
Healthcareworkers(HCWs)mayplayasignificantroleintransmittingpathogenswithinthehospitalsetting,andevenfromthehospitaltothe
community (and vice versa). A prospective ‘contact-diary’ survey of hospital-based HCWs (at 3 public hospitals in Singapore) investigated their
contact patterns, and compared these with working adults in the general population. Participants recorded their contact patterns (2-way con-
versation with ≥3 words or skin-to-skin contact) for 24-hour periods, demographics of the contact person, location of contact, and the contact
duration. Altogether, 211 HCWs and 1028 working adults reported 4066 and 15932 contacts respectively. HCWs reported more work-related
contacts(medianof13vs4),andlesshouseholdcontacts(2vs3).HCWsalsohadmorework-relatedskin-to-skincontacts(6vs1).Amongdifferent
HCWsubgroups,doctorsreportedthehighestwhileward-basednursesreportedthelowesttotalwork-relatedcontacts(17vs11).However,skin-to
skinwork-relatedcontactswerehighestforward-basednursescomparedwithotherHCWs(7vs5).Multivariatelinearregressionshowedsignificant
differences in work-related contacts among various HCW subgroups, adjusted for gender and institutional effects. It was concluded that HCWs
experiencedmorephysicalcontactsthanthegeneralpopulationandmayplacethemathigherriskofacquiringandspreadinginfections.
7.3. HumanmetapneumovirusandpediatricARIhospitalizationsinVietnam
KeisukeYoshihara,InstituteofTropicalMedicine,NagasakiUniversity,Nagasaki,Japan
Humanmetapneumovirus(hMPV)isaknowncauseforARI,andisespeciallycommonamongchildren(Edwardsetal.,2013).However,detailed
clinical and molecular epidemiological information of hMPV remain limited in the developing countries. The seasonal pattern and molecular
characterizationofhMPVinpediatricpatientshospitalizedforARIincentralVietnam,wasmonitoredaspartofapopulation-basedARIsurveillance
program(2007–2015).Atotalof6167caseswereenrolled;ofthese,206(3.3%)testedpositiveforhMPVbyamultiplexPCRassay.YearlyhMPV
incidencewas127(per100,000)amongchildren<5yearspriorto2009,whichincreasedto216(per100,000)intheperiod2010–2015.Therewas
no seasonal trend. The presenting feature included wheezing and pneumonia (58.5% and 34.1% respectively). hMPV Group-A and B were co-
circulating,withGroup-Abeingpredominantinmostoftheseasons.Time-scaledphylogenetictrees(Fgene)showedthattherecentlydominantA2c
lineagedivergedfromA2baround2004(95%HPD:2002–2006)andbecamedominantafter2009.Multivariateanalysisresultsindicatedthatcases
infectedwiththeA2blineagewereclinicallymoreseverethanA2c(adjustedOR6.30,95%CI1.65–24.09and6.93,95%CI2.34–20.50forwheezing
andpneumoniarespectively).GroupBvirusinfectionsappearedmilder.ThesefindingsindicatetheimportanceofhMPVinpediatricARIhospi-
talizations,andprovideusefulinformationforfuturesurveillanceandvaccinedevelopment.
7.4. GenomicandepidemiologicaldynamicsofRSVinAustralia
John-SebastianEden,TheUniversityofSydney,Sydney,NSW,Australia
RSV is one of the most important causes of severe respiratory infection in infants and young children, as well as in older adults and the
immunocompromised(Leeetal.,2013;Shietal.,2017).However,understandingofthedynamicsdrivingtheon-goingevolutionandepidemiology
of RSV transmission in humans is rather limited. To study genetic diversity, as well as potential baseline resistance to novel therapeutics, the
genomesofRSVstrainscollectedfromadultandpediatricpatientsinAustraliafrom2010−2016(RSV-A,n=70;RSV-B,n=80)wereamplified
andsequencedusinga4x4KboverlappingRT-PCRstrategythattargetedbothRSV-AandRSV-Bsubtypes.NexteraXTlibrarieswerepreparedand
sequencedusinganIlluminaMiSeq.Followingdenovoassembly,RSVsequenceswerealignedwithglobalreferencesandanalyzedusingaphy-
lodynamic approach. A distinct seasonality was observed with most infections occurring during the late winter period (with subtle shifts in the
seasonalrelativepredominanceofRSV-AandRSV-Bstrains).Multipleco-circulatinglineageswereidentifiedwiththeAustralianstrainsdispersed
throughout the global diversity. Spatial and temporal clustering was observed at local and regional scales highlighting the complex fine-scale
dynamics (e.g. institutional outbreaks), as well as gene flow within the Asia-Oceania region. This gene flow with local endemic lineages was
consistentwithotherrespiratorypathogenssuggestingviraltrafficisdrivenbyhumanmovementandinteractions.Astrong-temporalstructurewas
also observed with similar mean rates of evolutionary change at global scales for both RSV-A and RSV-B subtypes at 6.5 × 10−4 nucleotide
substitutionspersiteperyear(subs/site/year)and7.5×10−4subs/site/year,respectively.Likepreviousobservations,mostvariationwasfoundin
theGproteinandintergenicregions.However,fixedchangeswereobservedwithinthefusionproteinatpotentiallyantigenicsitesofrecentRSV-A
strains.ResistanceassociatedmutationsattheFproteinandthepolymerasegenesseemedrare.TheirdataaddtotheunderstandingofRSVgenetic
diversity,transmission,anddiseasedynamicswhichmaybenefitfuturevaccinedesign.
7.5. EtiologyandincidenceofSARIamonghospitalizedpatientsinMadagascar
NorosoaRazanajatovo,InstitutPasteurdeMadagascar,Antananarivo,Madagascar
TheetiologyandincidenceofSARIamonghospitalizedpatients,waspartofanon-goingsurveillanceprograminMadagascarfrom2014−2016.
Upperrespiratorysampleswereanalyzedforinfluenza,RSVandrhinovirususingreal-timeRT-PCRassay.Atotalof668patientswithSARIpatients
wereenrolled.Themedianagewas7years,withmostcases(n=318;47.6%)beingchildren<5yearsold.Thedetectionratesforinfluenza,RSV
andrhinoviruseswere21.7%(46/668),21.4%(143/668)and6.3%(42/668),respectively.Theagegroupof2–5yearswasmostaffectedbyRSV
(OR=14.2;P < 0.001);whereasagegroupsof5–15years(OR=2.5;P=0.026)and15–50years(OR=1.6;P=0.04)weremorefrequently
infectedwithinfluenzaviruses.TheoverallincidenceofSARIwas15,521.2per100,000person-years,whichvariedsignificantlyfromyeartoyear.
Theincidenceofinfluenza-associatedSARIwas3322.7per100,000person-years,withthehighestincidenceintheagegroupof15–50years(6864.6
per100,000person-years)(OR=2.9;P < 0.001).TheoverallincidenceforRSVwas3254.4per100,000person-years,withthehighestincidence
amongchildrenaged<2years(6103.8per100,000person-years)(OR=4.9;P < 0.001).Dataindicatedthatdiseaseburdencausedbythese
respiratoryvirusesishighinAfricancountries,particularlyamongchildren,andhighlightedtheimportanceofcontinuoussurveillancetoprovide
126
MeetingReport Antiviral Research 149 (2018) 118–142
dataforplanningofpublichealthmeasuresintheregion(Lafondetal.,2016;McMorrowetal.,2015).
8. PathogenesisofSARI
8.1. Whatpartdobacteriaplayinsevereinfluenza?
PeterOpenshaw,ImperialCollege,London,UnitedKingdom
Severe influenza may in part result from an over-exuberant host response driven by a high viral load, but bacterial overgrowth (usually of
resident pathogenic species such as S. pneumoniae and H. influenzae) can also contribute to morbidity and mortality (Lee et al., 2015). Due to
overlappingclinicalfeatures,empiricalantibacterialtreatmentisfrequentlyprescribed,perhapsunnecessarily, whereasempiricalantiviraltreat-
mentmaybeunder-utilized(Mylesetal.,2012).Therefore,itisimportanttodistinguishthesemechanismstorefineanddirectspecificantiviral,
antibacterial,and(potentially)immunomodulatorytherapy.Incaseswhereitisnotclearwhattherapytouse,thehostresponsetoinfectionmight
actasanindicator(for example,analysisoftranscriptionalsignaturesintheperipheralblood)(Suarez etal.,2015)butthedependence ofsuch
responsesonseverity,phaseandcomplicationsofinfluenzainfectionremainunclear.
AcomprehensiveanalysisofwholebloodRNAsignaturesandlocal/systemicmediatorswascarriedoutinacohortof256adultswithinfluenza-
like illness in 2009/10 and 2010/11 seasons (The Mechanisms of Severe Acute Influenza Consortium, MOSAIC.) (Cole et al., 2017). Interferon-
relatedantiviralpathwaysgeneswereoverexpressedduringtheearlyphaseofillness(0–5days),followedbyactivationoftheinflammatorycell
pathwaysincludingneutrophils,monocytesandNKcells(days5–10).Themolecularscoreswererelatedtoseverityandwereaffectedbybacterial
sepsis, but depended most critically on timing since onset of symptoms. Identification of specific patterns of immune activation that might be
amenabletotherapeuticmanipulationmayultimatelyassistinmanagementofinfluenza,butrequirecarefulinterpretation.
8.2. SeverityandphaselinkedvirusspecificCD4andCD8TcellresponsesinhumanpH1N1infection
HuiLi,CapitalMedicalUniversity,Beijing,China
TheroleofCD4andCD8Tcellresponsesininfluenzahasnotbeenfullycharacterized(Zhaoetal.,2012)Theantigen-specificTcellresponses
andcorrelationswithdiseaseseveritywereexaminedin79patientswithA(H1N1)pdm09influenzainfectionsinChina.Samplesweretakenduring
theacutephase(7 ± 3days)andrecoveryphase(21 ± 3days)andweretestedagainstliveA(H1N1)pdm09virusandpeptidepoolsofinfluenza
viruses.Thelongitudinalchangesininfluenza-specificCD4+andCD8+TcellresponseswithorwithoutpneumoniawerecharacterizedandTcell
activationandmigration-relatedcytokines/chemokinesinplasmaweremeasured.Comparedwithmilderinfections,influenza-specificCD4+and
CD8+ T cell responses and virus shedding were elevated in patients with pneumonia. During the acute phase of illness, effector CD8+ T cells
(CD45RA+CCR7-) with highly-expressed inhibitory immune receptor CD200R dominated the response (IFN-γ secreting). In the recovery phase,
effectormemoryCD4+T(CD45RA-CCR7-)cellswithhighly-expressedPD1,CTLA4andLAG3werehigherinthosewithsevereinfectionscompared
tomildinfections.ThemagnitudeofTcellresponsescorrelatedwithpneumoniaseverity(asindicatedbyPaO2/FiO2,lunginjuryscore,APACHEII
score).Inaddition,Tcellactivationandmigration-relatedcytokines/chemokineswereassociatedwithdiseaseseverity.ThusCD4+andCD8+Tcell
responsesmayplayaroleinpathogenesisanddiseaseprogressioninA(H1N1)pdm09pneumonia.
8.3. AIM2inflammasomeiscriticalforinfluenzainducedlunginjuryandmortality
JieruWang,UniversityofPittsburgh,Pittsburgh,USA
TheAbsent-In-Melanoma2(AIM2)inflammasomeisimportantinthehostresponseagainstarangeofbacterialandviralinfections,butlittleis
knownaboutitsroleinIAVinfection.ItisactivatedbydsDNAuponinfectionofcells,leadingtocleavageandactivationofcaspase1andcleavageof
IL-1β and IL-18 to their active forms. The role of AIM2 was studied using knock-out mice infected with lethal doses of IAV A/PR8/34 and A/
California/07/09.InAIM2-deficientmice,induceddsDNArelease,caspase-1activationandreleaseofcleavedIL-1βinthelungsweresignificantly
reduced.Inaddition,AIM2deficientmiceexhibitedattenuatedlunginjury(withfewerneutrophilinfiltration)andimprovedsurvivalagainstIAV
challenge;virusburdeninthelungwasunaltered.DeficiencyofAIM2wasnotshowntoaffecttheadaptiveimmuneresponseagainstIAVinfections.
InvitroexperimentswithsiAIM2treatedandAIM2deficienthumanandmouselungalveolarmacrophagesandtypeIIcellsindicatedamacrophage-
specificfunctionofAIM2intheregulationofIAV-stimulatedproinflammatoryresponses(Zhangetal.,2017).Thesefindingssuggestthatinfluenza
infectionactivatestheAIM2inflammasome,whichmayplayanimportantroleinIAV-inducedlunginjuryandmortality.
8.4. IdentificationofDDX19Basanessentialhostfactorforuncoatingstepduringinfluenzavirusentry
JihyeLee,InstitutPasteurKorea,RepublicofKorea
UsingsiRNA18,000hostgenesinhumanlungepithelialA549cellsweretargeted,andscreenedforeffectsonmulti-cycleinfectionofinfluenza
A/WSN/33 (H1N1) virus. Of 209 siRNAs which decreased IAV infection, the 20 top-scored siRNAs were further validated. A DEAD-Box RNA
helicases19B,DDX19B,wasidentifiedasanessentialfactorforIAVreplication.DepletionofDDX19BbysiRNAresultedinuptoa2log decreasein
10
virusyieldsinsingle-andmulti-cyclereplicationkinetics.Thegrowthdefectwasalsofoundinotherinfluenzasubtypes,includingA(H1N1)pdm09,
H3N2,H7N4,andtypeB.Theeffectwasearlysinceby4hoursafterinfection(pi)levelsofmRNAandvRNAwerereduced.NormallytheRNPsare
importedintothenucleusby3–4hourspi,buttherewaslittleNPstaininginthenucleus.Furthermore,therewasnoM1staininginthecytoplasm,
indicatingthatwhileDDX19BisknowntofunctioninmRNAnuclearexport,theblockwasearlierattheuncoatingstep.Thiscontrastswithothers
whoshowedtheDDX19BenhancedthenuclearexportofinfluenzamRNA(Diotetal.,2016).
8.5. StudiestogaininsightsintodrugresistanceofinfluenzaA(H7N9)viruses
LarisaGubareva,CentersforDiseaseControlandPrevention,Atlanta,GA,USA
TherearestillnoestablishedcorrelatesofclinicallyrelevantresistancetotheNAIs(Lietal.,2015).Somevirusesmayshowreducedfitnessin
vitro or in vivo, while others retain their fitness. Influenza A(H7N9) wild-type (WT) and mutant viruses were propagated, plaque-purified, and
127