Predicting intention to uptake H1N1 influenza …eprints.hud.ac.uk/11631/1/BJHP.pdf2009). On June...
Transcript of Predicting intention to uptake H1N1 influenza …eprints.hud.ac.uk/11631/1/BJHP.pdf2009). On June...
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Title
PredictingintentiontouptakeH1N1influenzavaccineinauniversitysample.ClaireByrne1,JaneWalsh1,SusannaKola2,andKiranSarma1*
1SchoolofPsychology,NUIGalway,RepuplicofIreland2DepartmentofBehaviouralandSocialSciences,UniversityofHuddersfield,UKCorrespondingauthor:DrKiranSarma,SchoolofPsychology,NUIGalway,RepublicofIrelandEmail:[email protected]
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Abstract
Objective:GlobalpandemicH1N1wasatypicalofinfluenzainthatitwas
associatedwithhighsymptomseverityamongyoungadults.Highereducation
institutionswerethereforeunderstandablyconcernedaboutthepotentialfor
highinfectionratesamongstudents.Thisstudyexaminedintentiontouptake
H1N1vaccinebetweenNovemberandDecember2009,whentheviruswas
classifiedbytheWHOasbeinginthepandemicphase.
Design:Across‐sectionalsurveydesignwasemployed.
Method:Two‐hundreduniversitystudentscompletedaquestionnairebattery
comprisedofhealth,belief/attitudes,andbehaviouralintentionmeasures.
Results:Findingssuggestedthatnon‐intentiontovaccinateisassociatedwitha
strongdisbeliefinitsefficacy,innegativeattitudestowardsvaccinations,andin
lackofperceivedthreat,whichisunderscoredbyadisinterestinothers’
opinions,includingauthoritativebodies.Findingsalsosuggestedthatthereis
resistancetotheideaofvaccinationsbeingmandatory.
Conclusions:Vaccinationintentisinsomewaylinkedtoarangeofattitudesand
beliefs.Theimplicationforhealthpractitionersisthatbehaviourintentmaybe
opentoinfluencewherepsycho‐educationcancreatepro‐vaccineattitudesand
beliefs.
Keywords:H1N1,HBM,swineinfluenza,TPB,vaccination.
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1.Introduction
Influenzaisamajorpublichealthchallenge,affecting5‐30percentoftheglobal
populationeachyear(WHO,2003).TheWorldHealthOrganisation(WHO)
estimatesthatannualinfluenzaepidemicscausebetweenthreeandfivemillion
casesofsevereillnessworldwide,andpotentiallyhalfamilliondeaths(WHO,
2009).OnJune11,2009WHOdeclaredaphase6pandemicalertforinfluenzaA
(H1N1),commonlyreferredtoas‘swineflu’,anovelrecombinantofpreviously
identifiedviruses.H1N1wasatypicalofinfluenzainthatitdisproportionately
impactedthoseundertheageof35.Bymid‐September2009H1N1hadspreadto
over70countrieswith500,000confirmedcasesandinexcessof3,000deaths
(Girard,Tam,Assossou,&Kieny,2010).
TheglobalresponsetoH1N1wastointroduceimmunisation
programmes.IntheRepublicofIrelandvaccineswereinitiallymadeavailableto
keytargetgroups(October‐December2009)andlaterthebroaderpopulation
(early2010).ByAugust10th,2010,whentheWHOdeclaredH1N1tobeinpost‐
pandemicphase,morethan1000peoplehadbeenhospitalisedsufferingfrom
H1N1‐relatedcomplicationsintheRepublicofIreland,100hadbeentreatedin
intensivecareunits(ICUs)and27deathshadbeenrecorded(Departmentof
HealthandChildren,2010).EightypercentofallcasesrecordedbytheHealth
ProtectionSurveillanceCentre(HPSC)herewereamongthoseundertheageof
35.
Thesuccessofimmunisationprogrammesismoderatedbythelevelof
vaccineuptakeinthepopulation,andthusconsiderableefforthasbeeninvested
ininvestigatingfactorsthatinfluenceandpredictintentiontouptakevaccines.A
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numberofsocialcognitivetheorieshavebeenappliedtothisbehaviourinthe
past,inparticulartheTheoryofPlannedBehaviour(TPB)(Ajzen,1985)andthe
HealthBeliefModel(HBM)(Becker,1974;Becker&Rosenstock,1987).TheTPB
isanextensivelyappliedhealthpsychologymodelandpostulatesthatthemost
immediatedeterminantofaperson’sbehaviouris‘behaviouralintent’.Although
ithasbeensuccessfullyappliedtomanyhealthbehavioursinthepast(e.g.
Hagger,Chatzisarantis,&Biddle,2001;Mason&White,2008),recentresearch
onintentionstovaccinateagainstinfluenzarevealedthattheonlyTPBvariable
thatsignificantlypredictedintentiontovaccinatewassubjectivenorm,
explaining48%ofthevarianceinintention(Gallagher&Povey,2006).
TheHBMhasbeenappliedinmanycontextsincludingresponsetoillness
symptoms,preventivescreening,andobtainingvaccinations(Becker&
Rosenstock,1987;Chen,Fox,Cantrell,Stockdale,&Kagawa‐Singer,2007;deWit,
Vet,Schutten,&vanSteenbergen,2005;Harrison,Mullen,&Green,1992;Lewis
&Marlow,1997;Stretcher&Rosenstock,1997;Umeh&Rogan‐Gibson,2001;
Weinsteinetal.,2007).TheunderlyingconceptoftheHBMisthatbeliefsabouta
disease,andstrategiestoreduceitsoccurrence,determinehealthbehaviour.The
HBMcontainsfourmaincomponents:perceivedsusceptibilityto,andperceived
severityofadisease;andperceivedbarriersandperceivedbenefitsof
preventativestrategies(e.g.vaccinating)againstadisease.
Zijtregtopetal.recentlyexaminedintentiontouptakevaccinationfora
pre‐pandemicinfluenza(‘avianflu’;H5N1)inanationalsamplefromthe
Netherlands(Zijtregtopetal.,2010).Thestudyoutcomeswereanintentionto
vaccinate‘iftherewasapandemic’or‘atthemoment’ifrequestedbythe
government–bothhypotheticalscenarios.Theresearchwasheavilyinfluenced
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bytheHBM.Coincidentallythetimeofsurveyadministration(April2009)
coincidedwiththeWHOpre‐pandemicalertforH1N1.Of508respondents,34.5
percentreportedanegativeintentiontovaccinate.Negativeintentionwas
significantlyassociatedwithlow:perceivedriskofinfection;riskofdeathif
infected;certaintythatvaccinationwillprotectagainstfutureinfection;
perceivedriskamongthose‘close’totheparticipant;andwillingnesstoaccept
advicefromthegovernment.Being‘againstapandemicinfluenzavaccinationin
particular’wasalsoassociatedwithnegativeintent.Thesesixfactorscorrectly
classified80%ofthesample(Zijtregtopetal.,2010).
Thepresentresearchbuildsonthistheme,butdiffersinanumberof
respects.First,itexaminesintentiontouptakevaccineduringadeclared
pandemic,andattheheightofthatpandemicalert.Thisimprovesthevalidityof
findingsinthatthecross‐sectionalsnap‐shotwastakenatatimewhenmedia
campaignspromotingvaccineuptakewouldnormallybedisseminated.
Second,theoutcomevariable,intentiontovaccinate,wasnot
hypothetical.TheIrishgovernmentwasactivelypromotingvaccinationfrom
H1N1andparticipantswereaskedabouttheiractualbehaviouralintentrather
thanpresentinga‘whatif’scenario.
Third,thestudydealswithaspecificat‐riskgroup,universitystudents,
whoareatriskofinfluenzaduetolife‐style,mobility,andsocialinteraction
(Henrich&Holmes,2009;Van,McLaws,Crimmins,MacIntyre,&Seale,2010),
butwereofparticularconcerngiventheclinicalpatternofH1N1.
Fourth,itincludesadditionalvariablesofinterest,includingself‐efficacy,
conscientiousness,comparativeoptimismandtrust‐in‐authoritieswhichhave
beenassociatedwithhealthdecisionmakingelsewhere(Anderson&Tverdova,
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2001;Bogg&Roberts,2004;Colgrove&Bayer,2005;Friedmanetal.,1995;
Goodwin&Freidman,2006;Jerusalem&Schwarzer,1992;Raynor&Levine,
2005;Walton&Roberts,2004;Wilson,Schneider,Arnold,Bienias,&Bennett,
2007).Trustinauthorities,ameasureoftheperceivedtrustworthinessofthe
Governmentanditsagents,wasincludedspeculativelyastheRepublicofIreland
wasinaperiodofeconomicdeclineandincreasedpublicdissatisfactionwiththe
Government.Trustinauthoritiesmaybeassociatedwithawillingnessto
vaccinatewhenrecommendedtodosobytheState.Self‐efficacyhasbeenshown
topredictawiderangeofhealthbehavioursincludingweightcontrol,
contraception,smokingandexerciseandresearchsuggeststhatinterventions
targetingself‐efficacycanhaveanimpactonbehaviourchange(Strecher,
McEvoyDeVellis,Becker&Rosenstock,1986).
Optimisticbias,inthecontextofhealthbehaviour,referstoabeliefthat
thechanceofexperiencinganillnessislowerforoneselfthanothers.Itis
believedthatthebiasinfluencesmotivationtoengageinpreventativehealth
behavioursandhasbeenshowntopredictperceivedsusceptibilitytoarangeof
illnesses(forareviewseeHelweg‐Larsen&Shepperd,2001).Conscientiousness
wasmeasuredasthereisaconsiderablebodyofliteraturesuggestingthatthe
trait,andrelatedtraits,arerelatedtolongevityandthishasbeensupportedbya
meta‐analysisinthearea(Bogg&Roberts,2004).
Basedontheliteraturecitedearlier(Gallagher&Povey,2006;Zijtregtop
etal.,2010),weexaminedthepredictiveutilityofhealthbeliefvariables
(susceptibility,severity,barrierstovaccinationandbenefitsofprevention),and
exploredtheadditionalvalueofincludingsubjectivesocialnormsrelatingto
vaccination(Gallagher&Povey,2006).Wehypothesisedthatmeasuresof
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individualdifference(conscientiousnessandoptimismbias)andtheHBM
variableswouldbesignificantpredictorsofbehaviouralintent,andthat
subjectivesocialnorms,wouldaddadditionalexplanatoryvaluetotheinitial
model.
2.Method
2.1.Designandparticipants
Asampleof200students(142femalesand58males)in3rdlevel
educationattheNationalUniversityofIrelandGalwayservedasstudy
participantsinthiscross‐sectionalsurvey.Allparticipantswereundertakingthe
firstsemesterofanundergraduateprogramandstudentswererecruitedfrom
generalartsandhealth‐relatedstudies(medicine,occupationaltherapyand
speechandlanguagetherapy)inordertoachievearepresentativesample.The
questionnairewasself‐administeredingroups.
2.2.Materialsandmeasures
The106‐itemquestionnaireincorporatedelementsoftheprotocolused
byZijtregtopetal.(2010)andassessedbehaviouraldeterminantsofintentionto
vaccinatebasedoncomponentsoftheHBMandotherrelevantvariablesof
interest,detailsofwhichareprovidedbelow.
2.3.Outcomemeasure
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TheprimaryoutcomewastheintentiontobeimmunisedagainstH1N1
whichwasmeasuredbyasingleitem;“Ifthegovernmentrequestsallstudentsto
havetheswine’fluvaccination(SFV),wouldyoutakethevaccinationwhenmade
available?”.Respondentshadthechoicetoreplyyes,no,ordon’tknow.Priorto
completingtheitemsrelatingtoinfluenza,thequestionnairedescribedH1N1as
‘anewstrainof‘flu(swineinfluenza)whichisknowntobepandemic,i.e.ithas
spreadthroughouttheworld’.
Healthstatus(medicaldeterminant)wasmeasuredusingtheHealth
ServiceExecutive’s(HSE)listofat‐riskpopulationsforH1N1.Thelistcomprised
10itemsincludinglong‐termlungdisease,diabetes,andimmuno‐suppression,
whererepliesofyesornoindicatedapositiveornegativepresenceofachronic
illness.
TrustinAuthoritieswasmeasuredusingitemsthataddressedtrustinthe
governmentandintheHealthServiceExecutive(HSE)inproviding“thebest
possibleadviceregardingmyhealth”.Participantsreportedtheiragreement
withthestatementonascalefrom0to100,andameanofthetwoitemswas
usedasameasureof‘trust’.
ComparativeoptimismwasmeasuredusingHarrisandMiddleton’s14‐
itemscale(Harris&Middleton,1994)toassesstheperceivedlikelihoodof
contracting,incomparisontoanotherperson,14medicalconditions.
Participantsratedeachpotentialhealthproblemonafive‐pointlikert‐scalefrom
muchmorelikely(1),tomuchlesslikely(5).Themeanofeachrespondent’s
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fifteenratingswasthentakenasameasureofgeneralizedcomparativeoptimism
relatingtoperceivedhealththreats,withahigherscoreindicatinggreater
optimism.
Conscientiousnesswasevaluatedusinga48‐itemsubscalefromthe
RevisedNEOPersonalityInventory(Costa&McCrae,1992).Responseoptions
werescoredonafive‐pointlikertscalerangingfromstronglyagree(5)to
stronglydisagree(1),withreversedscoringwhereappropriate.Ahigherscore
indicatesgreaterlevelsofconscientiousness.
Self‐efficacywasassessedbytheGeneralisedSelf‐EfficacyScale
(Jerusalem&Schwarzer,1992)comprising10itemsreflectinganindividual’s
generalizedself‐efficacybeliefs.Statementswerepositivelyphrasedsuggesting
goodcopingabilities(e.g.,“Itiseasyformetosticktomyaimsandaccomplish
mygoals”).Respondentsratedstatementswithscoresrangingfromnottrueat
all(1)toexactlytrue(4).Ahigherscoreindicatesgreaterlevelsofself‐beliefin
abilitytocopewithavarietyofdifficultdemandsinlife.
QuestionspertainingtothecomponentsfromtheHBMwerebasedon
previousinfluenzaresearch(Zijtregtopetal.,2010),andadditionalvariables
measuringattitudesandsocialinfluencewerealsoadoptedfromthissourceand
adaptedtorelatetoH1N1.Themeasuresareasfollows:
ThePerceivedbenefitsofvaccinationwereassessedbythreeitems–not
contractingH1N1ifvaccinated;enduringlessseveresymptomsifcontracted;
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andnotinfectingothers.Responseswereonafive‐pointlikertscaleranging
fromstronglyagree(5)tostronglydisagree(1).Ahigherscoreindicatesgreater
perceivedbenefitsofbeingimmunised.
Perceivedsusceptibilitywasmeasuredwithtwoitemsthatprobed
perceivedriskofcontractingH1N1andriskofotherscatchingH1N1.The
responseformatwasafive‐pointlikertscalefromstronglyagree(5)tostrongly
disagree(1).Ahigherscoreindicatesgreaterperceivedsusceptibilitytoswine
flu.
Perceivedseveritypertainedtothedangersperceivedbytherespondentif
theyweretocontractH1N1,andincludeddangertoself,toothers,riskof
infectingothers,andriskofdying.Answersweregivenonafive‐pointlikert
scalerangingfromstronglyagree(5)tostronglydisagree(1)forquestionswitha
positiveoutcomeforintentiontovaccinate,withreversescoringforquestions
withanegativeoutcome.Ahigherscoreindicatesgreaterperceivedseverityof
H1N1.
Perceivedbarrierstowardsintentiontovaccinateweremeasuredbythree
items,andresponsesweregivenonafive‐pointlikertscalerangingfrom
stronglyagree(5)tostronglydisagree(1).Barriersincludedbeingagainst
vaccinationingeneral,H1N1vaccinationinparticular,andabeliefthatswine’flu
vaccination(SFV)cancauseH1N1.Ascodedduringanalyses,ahigherscore
indicatesgreaterperceivedbarrierstowardsbeingimmunisedagainstH1N1.
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Attitudeswereevaluatedbyaskingparticipantstorespondtosixitems
whichincludedsocialandpersonalbeliefs(e.g.‘IcanprotectmyselfagainstSF
bytakingSFV’;‘ItisimportanttofollowtheadviceofthegovernmentaboutSFV’;
and‘IfpeopleinmyenvironmentgetvaccinatedagainstSF,itisunnecessaryfor
metogetavaccination’).Responsesweremeasuredonafive‐pointlikertscale
rangingfromstronglyagree(5)tostronglydisagree(1).Ascodedhere,ahigher
scoreindicatesmorepositiveattitudestowardsimmunisationagainstH1N1.
Socialinfluenceswereindicatorsoftheimportanceofothersandtheir
opinions,andparticipantswereaskedtorespondtothreeitemsonafive‐point
likertscalerangingfromstronglyagree(5)tostronglydisagree(1).Social
influencesweremeasuredbyusingthestem‘Itisimportanttofollowtheadvice
of….’andincludedarangeofsignificantothers,namelytrustedauthorities
(governmentanddoctor),andfamilyandfriends.Ahigherscoreindicates
greatersocialinfluence.
2.4.Procedure
Participantswereprovidedwithadocumentexplainingthenatureand
intentionoftheresearchasexaminingpsychologicalpredictorsofhealth
behaviouramonguniversitystudents.Subsequentlytheycompletedaninformed
consentdocumentandcompletedthequestionnairebattery.Participationinthe
researchwasvoluntaryandstudentswerenotrequiredtoparticipateaspartof
theirprogrammeofstudy.
2.5.Statisticalanalysis
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DatawereanalysedusingSPSSforwindows(version17).Median
differencesinbehaviouraldeterminantsbasedonsplitsontheoutcomemeasure
wereanalysedusingKruskal‐Wallis,associationsbetweenintentionand
categoricalvariableswereanalysedusingChi‐Square.Logisticregressionwas
performedtoassesstheimpactofthebehaviouraldeterminantsonintentionto
bevaccinated.
3.Results
3.1.Group‐basedcomparisons
One‐hundredandtwentyseven(63.5%)respondentsindicatedthatthey
intendedtobeimmunised(yesgroup)ifthegovernmentrequestedallstudents
tohavetheswine’fluvaccination.Thirty‐five(17.5%)didnotintendtovaccinate
(nogroup)and36(18%)saidtheydidnotknow(don’tknowgroup).Eight(4%)
respondentspurportednottohaveheardofswine’flu,and190(96%)saidthey
had.Onehundredandtwenty(65%)reportedthattheyknewsomeoneintheir
environmentwhohadhadswine’flu.
Forty‐onerespondents(29=yesgroup,8=nogroup,4=don’tknow
group)listedthemselvesintheat‐riskcategoriesasdelineatedbytheHSE
representing20.5percentofthesample.Twenty‐eightofthese(68%)suffered
long‐termlungdisease(asthma),whilepregnancy,immunosuppression,
haemoglobinopathies,morbidobesity,andlong‐termheart,kidney,liverand
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neurologicaldiseaseseachaccountedforlessthatonepercent.Themajorityof
people(71%)whoself‐reportedthemselvesas‘at‐risk’intendedtovaccinate.
Themeans,standarddeviations,andCronbachforpredictorvariables
areprovidedinTable1.Nodifferencesacrossgroupsemergedforlevelsof
conscientiousness,self‐efficacy,optimism,severityandsusceptibility.
Differencesdidemergeforattitudes(H(2)=69.84,p<.0005),perceivedbarriers
(H(2)=46.64,p<.0005),externalsocialinfluence(H(2)=27.06,p<.0005)and
perceivedbenefits(H(2)=6.12,p<.05).Post‐hoctestsindicatedthattheno
group(M=15.81,SD=2.83)expressedsignificantlylesspositiveattitudes
towardstheintentiontovaccinatethanboththeyesgroup(M=21.53,SD=2.99,
U=336,z=‐7.261,p<.005,r=‐.58)andthedon’tknowgroup(M=18.18,SD=
2.71,U=302,z=‐3.123,p=.002,r=‐.39).Significantdifferenceswerealso
foundbetweenthosewhosaidyesanddon’tknow(U=865.5,z=‐5.281,p<.005,
r=‐.42).Barrierswererevealedtobesignificantlyhigherinthenogroup(M=
9.19,SD=2.67)thantheyesgroup(M=5.88,SD=1.95,U=609.5,z=‐6.087,p<
.005,r=‐.49)andthedon’tknowgroup(M=7.47,SD=1.67,U=297,z=‐3.204,
p=.001,r=‐.40).Thedon’tknowgroupalsoperceivedmorebarriersto
vaccinationthantheyesgroup(U=1164.5,z=‐4.039,p<.001,r=‐.32).Social
influencehadalesserimpactonthenogroup(M=8.60,SD=2.87)thanthose
whointendedtovaccinate(M=11.3,SD=1.69,U=967.5,z=‐5.079,p<.001,r=
‐.40)andthedon’tknowgroup(M=10.94,SD=1.64,U=326.5,z=‐3.536,p<
.001,r=‐.42).Benefitsperceivedbythenogroup(M=8.21,SD=2.23)andthe
yesgroup(M=9.36,SD=2.13,U=1558,z=‐2.408,p=.016,r=‐.19)werejustat
significancelevels.
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Age,however,variedwithintentiontovaccinate(H(2)=8.3,p<.05),and
Mann‐Whitneyposthoctestswereusedtofollowupthisfinding,witha
Bonferronicorrectionapplied.Theyrevealedthatthenogrouphadtheoldest
profile(M=23.60,SD=8.27),withsignificantdifferencesbetweenboththem
andtheyesgroup(M=20.45,SD=6.33,U=1555,z=‐2.832,p=.005,r=‐.22)
andthedon’tknowgroup(U=422.5,z=‐2.446,p=.014,r=‐.29)whowerethe
youngest(M=19,SD=2.19).Achi‐squareanalysisrevealednoassociation
betweengenderandintentiontovaccinate(χ2(2)=.33,p>.05).Trustin
authoritieswasalsonon‐significant.
3.2.Correlationanalyses
Subsequentanalysiswasrestrictedtothosewhodointendanddonot
intendtovaccinate.‘Don’tknows’wereexcludedfromtheanalyses.Biserial
correlationswereconductedforintentionagainstallthepredictorsduetothe
dichotomousnatureofthedependentvariable(Table2).Allothercorrelations
conductedwereSpearman’srho.Multicollinearitydiagnosticsrevealednostrong
relationshipsbetweenthepredictorvariables(r<.9).VIF(<10)andtolerance
(>.1)valueswerealsoadequate(Howitt&Cramer,2008).Zero‐order
correlationswithintentionarereportedamonggender,trustintheauthorities,
optimism,conscientiousness,self‐efficacy,andsomecomponentsoftheHBM.
Age(rpb=‐.22),attitude(rpb=.58),socialinfluence(rpb=.41),andperceived
barriers(rpb=.49)weresignificantlycorrelatedwithintentionatp<.01,and
perceivedbenefits(rpb=.19)atp<.05.
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Logisticregressionwasperformedwithintentiontovaccinate(yes/no)as
criterionandthestatisticallysignificantcorrelatesofintention(age,barriers,
benefits,attitudesandsocialinfluence)aspredictors(Table3).Variableswere
enteredinblocks,withageinblock1,perceivedbarriersandperceivebenefits
(HBM)inblock2,andsocialinfluenceandattitudesinblock3.At‘block0’the
analysisassumedthefullsampleintendedtovaccinate,meaningthatatbaseline
themodelcorrectlyidentifiedallthosewhointendtovaccinate(100%),but
noneofthosewhodidnotintendtovaccinate(0%).Addingageintotheanalysis
atblock1increasedthespecificityofthemodel,correctlypredicting6.7percent
ofthosewhodidnotintendtovaccinate,and97.5percentofthosewhodid,and
79.1percentofallcases.Addingperceivedbarriersandperceivedbenefitsin
block2enabledthemodeltocorrectlyidentify40.0percentofthosewhodidnot
intendtovaccinate,and94.9percentofthosewhodid(overall83.8percentof
casescorrectlyidentified).Finally,addingsocialinfluenceandattitudesledtoa
modelcorrectlyidentifying73.3percentofnon‐intenders,and96.6percentof
thosewhodidintendtovaccinate(overall91.9%).
Eachstageoftheanalysiswasstatisticallysignificantandsummary
resultsarepresentedinTable3.Thefullmodelcontainingallthepredictorswas
statisticallysignificant2(5)=83.28,p<.0005,indicatingthatthemodelcould
distinguishbetweenthosewhohadanegativeintentiontovaccinateandthose
whointendedtovaccinate.Themodelasawholeshowedgoodpredictiveutility,
correctlyclassifying91.9percentofcases,andexplainingbetween43percent
(CoxandSnellR2=.43)and68percent(NagelkerkeR2=.68)ofthevariancefor
anegative‐intentiontovaccinate.Inthefinalblockonlytwoofthepredictor
variables,attitudes(Wald=16.6,p<.00051.89)andbarriers(Wald=7.68,p<
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.01),emergedassignificantpredictors,althoughagehadbeensignificantin
block1(Wald=7.04,p<.005).
Subsequentanalysesofthebarrierandattitudevariables(Table4)
showedthatsignificantlygreaterdoubtsareexpressedbythenogroupastothe
efficacyofvaccinations,andinparticulartowardstheH1N1vaccine.Incontrast,
theyesgroupdisplayedgreaterpositiveattitudestowardthevaccinationissue.
Itisalsoimportanttonotethatinpreliminaryanalysisthatexcluded
‘attitudes’fromtheregression,socialinfluencewasasignificantcontributorto
themodel(Wald=5.14,p=.023),whichmaysuggestthat‘attitudes’occludedthe
importanceofsocialinfluenceinthemodelreportedhere.Thisisconsideredin
greaterdetaillaterinthispaper.
4.Discussion
Theresearchidentifiedanumberofimportantaspectsofthevaccination
climateintheRepublicofIrelandatatimewheninfectionwasatpeaklevelsand
theauthoritieswereengagedinintensivepublichealthcampaignstopromote
uptake.Inthisclimate,64percentofuniversitystudentsinoursamplereported
anintentiontohavethevaccination.IntheOctober‐Decemberadministration
window,peopleweredyinginIrelandfromH1N1,theviruswasinpandemic
stage,studentswereaspecificat‐riskpopulation,andtheauthoritieswere
heavilyinvestedinpublichealthcampaignseducatingaudiencesabouttherisks
ofH1N1andtheimportanceofvaccination.Thefindingwouldsuggestthatthis
campaignwasworkingforalargeproportionofthestudentpopulation.
Eighteenpercentofoursampledidnotintendtotakeupthevaccination.
ThisisconsiderablylowerthanthatreportedintheDutchstudyreviewed
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earlier(Zijtregtopetal.,2010)probingvaccinationintentforH5N1avianflu,
where34.5percentofthepopulationsamplereportedthattheywouldnotbe
vaccinated.Thisdiscordancecanbeexplained,atleastinpart,bythefactthatthe
Dutchfigurewasforpre‐pandemicinfluenzaandbydifferencesinsample
designs.Furthermore,theDutchstudyposedahypotheticalquestionwhere
respondentswereaskediftheywouldtakethevaccinationifaskedbythe
authorities.Inourstudy,vaccinationforH1N1wasavailableandtheauthorities
intendedtovaccinatethepopulation.
Thesecondimportantfindinghereisthatadistinctprofileemergedfor
thosewhodidnotintendtovaccinate.Incomparisontothosewhointendedto
vaccinate,thosewhodidnotreportedsignificantlyfewerpositiveattitudes
towardsvaccination(largeeffectsize),greaterperceivedbarrierstovaccination
(mediumeffectsize),werelessinfluencedbyexternalinfluences(GPandfamily
andfriends)encouragingvaccination(mediumeffectsize)andperceivedless
benefitsofvaccination(smalleffectsize).Thisgroupwasalsosignificantlyolder
thatthosewhointendtovaccinate(smalleffectsize).
Lookingspecificallyatcomponentsofthesebehaviouraldeterminants,a
numberofitemsemergedasbeingimportant.Incontrasttothosewhointended
tovaccinate,thosewhodidnotreportedgreateroppositiontovaccinationsin
general,andalsospecificallytoH1N1vaccination.Conversely,thosewho
intendedtovaccinatereportedastrongerbeliefthatvaccinationforH1N1
protectsagainsttheinfectionandthatvaccinationshouldbemandatory.Thisis
inlinewithresearchsuggestingthatwhereimmunizationprogrammesare
obligatory,thereisagreateruptakeinvaccinations(Colgrove&Bayer,2005).
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Ofparticularinteresttohealthpromotionpractitioners,thosewho
intendedtovaccinatereportedhigherlevelsofpro‐vaccineattitudesamongtheir
GPsandclose‘others’thanthosewhodidnotintendtovaccinate,potentially
pointingtowardsanimportantsocialinfluencemechanisminvaccinebehaviour.
Thesefindingsareofgreatimportanceastheypointtowardsapossible
causallinkbetweenattitudesandbehaviour.Whiletheoriginsoftheseattitudes
needfurtherexploration,theyarelikelytobemanifestationsofprevious
knowledgegarneredfrompastexperience,peers,authoritativebodies,andthe
media(Jewell,2001;Zajonc,1984).Thereisscopehereforfurtherinvestigation
toelucidatehowsuchabeliefbecomesestablishedandwhetherornotthe
findingsholdforanationallyrepresentativesample.Thisinvestigationshould
includevariablesthatmorecloselymapontotheTheoryofPlannedBehaviour
(TPB).
Inapredictivemodelcontainingbehaviouraldeterminantsofintention,
theperceivedbarriersandattitudestowardsvaccinationpredictedbetween43
percentand68percentofintention,inlinewithpreviousresearch(Hofmann,
Ferracin,Marsh,&Dumas,2006;Hollmeyer,Hayden,Poland,&Buchholz,2009).
Perceivedbarrierstovaccination,andabeliefthatitisimportanttoget
vaccinatedevenifthoseintheenvironmentarevaccinated,weresignificant
contributorstothemodel.Theformerfindingresonateswiththeexistent
literature,withperceivedbarrierstoactionassociatedwithcompliancewith
recommendedhealthbehaviour(Hollmeyeretal.,2009;Janz&Becker,1984;
Umeh&Rogan‐Gibson,2001),includinginoculation(Hofmannetal.,2006).
Contrarytoexpectations,perceivedbenefitsofvaccinationandsocial
influencedidnotcontributetothismodel.Thismayreflectlowinternal
19
consistencyofthe2‐itembenefitsscale(=.52)andaneedtoreconsiderhow
besttomeasureperceivedbenefit.Certainlyresearchandtheoryisstrongly
suggestiveoftheimportanceofbothbeliefsandperceivedbenefitsin
determiningbehaviourchange(Becker&Rosenstock,1987).
Theroleofsocialinfluenceislesseasilyexplained.Theitemsmeasuring
‘attitude’includedonethatrelatedto‘followingadvice’,whichpotentially
overlappedwithsocialinfluence.Moreover,thevariablessocialinfluenceand
attitudeswerestronglycorrelated(r=.63,p<.01).Thisraisesthepotentialforthe
attitudesvariabletooccludethecontributionofthesocialinfluencevariablein
theresults.Whenthelogisticregressionwasre‐runwithouttheattitudes
variable,socialinfluenceemergedasasignificantcontributor.Thishas
importantimplicationsforfutureresearch,whichshouldcarefullyconsiderhow
attitudesandsocialinfluencecanbebestmeasured.CertainlytheTheoryof
PlannedBehavior(TPB),whichensuresthatattitudesandsocialinfluencesare
measuredasdistinctconcepts,providesausefulframeworkforaddressingthis
limitationofthecurrentstudy.
Self‐efficacy,comparativeoptimismandconscientiousnesswerenon‐
significantcorrelatesofintentiontobevaccinated.Ononelevel,thesenegative
findingsmayinpartreflectthewayH1N1wasportrayedinmediacoverageof
thepandemic.Theillnesswasdescribedaseasilypreventablethrough
vaccination‐thusself‐efficacymaybelessrelevantinthisspecificdisease.
Similarly,itwasportrayedasspreadingeasilyfromoneindividualtothenext,so
evenbeliefsthatinfectionissomethingthatismorelikelytobeexperiencedby
others(optimistbias)wouldlogicallyincreasethelikelihoodofinfectionofthe
respondent.
20
Onasecondlevel,themeasuresmayhavelackedsensitivityinpredicting
intentiontovaccinate.Behaviourspecificmeasuresofself‐efficacyand
conscientiousnessmayhaveresultedinabettertestoftheimpactofthese
factorsonintendedbehaviourandthisshouldbeconsideredinfutureresearch
inthisarea.
Theresearchwouldconcludethatintentiontovaccinateislinkedto
behaviouraldeterminantsthatgobeyondonetheoreticalmodelofbehaviour.
PerceivedbarrierstowardsvaccinationemergedfromtheHBMasapredictorof
behaviourintent.‘Attitudes’alsoemergedasimportant.Whilethestudydidnot
directlytesttheTheoryofPlannedBehaviour(TPB),attitudesiscentraltothis
theoryandfutureresearchshouldprobethistheorymoredirectly.
Itisalsoimportanttonotethatthefindingsreportedherearenot
necessarilyvalidinunderstandingotherhealthbehaviours.Atthetimeof
administrationH1N1wasapotentiallyfatalillnessforuniversitystudents,the
dangerwasimmediate,andthebarrierstoimmunizationarelow(e.g.,Painteret
al.,2010).Thisisincontrasttootherillnesssuchascoronaryheartdisease,
wherepreventionrequireslong‐termcommitment(Armitage,2005),andthe
immediatesalienceofdeathbycoronaryheartdiseasemaybelow.Forsuchan
illness,perceivedbehaviouralcontrolmaybeamorepowerfulpredictorof
behaviourintent(Johnstonetal.,2004).
Theexternalvalidityofthefindingstothebroader3rdleveleducation
studentpopulationislikelytohavebeenhamperedbyamarginalunder‐
samplingforprobingapredictivemodel.Itisreassuringthatthe95%confidence
intervalsofexp(B)didnotspanacross1,butitisstillanticipatedthatalarger
samplewouldhavebeenmoresensitivetoalargerpredictivemodel.Asnoted
21
earlier,thereisalsosomeconcernabouttheitemsmeasuringperceivedbenefits
ofvaccination,andwewouldrecommendthatfuturestudiesre‐thinkhowsucha
conceptshouldbemeasured.Itwouldalsobeusefultoextendtheenquiryand
consideraffectivepredictorsofbehaviourintent,includinganticipatedregret,
whichmaybeparticularlyimportantinunderstanding,andrespondingto,those
whodonotintendtovaccinate.
Itisimportanttoreiteratethatthisstudytargetedaspecificat‐risk
population.Thematterofbroaderpopulationrepresentativenessisnotanissue,
andnoinferenceastobroaderpopulationuptaketrendsarebeingmadehere.
Wewouldnote,however,thatthesampleutilisedhere,whilebroadly
representativeofundergraduatestudentsattendingauniversityintheWestof
Ireland,isnotnecessarilyrepresentativeofthestudentpopulationnationally.
Amorepressinglimitationofthisresearchisthattheitemsusedto
measureperceivedbarriers,severityandattitudeswerebasedlargelyon
researchfromotherjurisdictions(Zijtregtopetal.,2010)andfutureresearch
shouldincludeprimaryexploratoryresearchtoensuremeasuresaresensitiveto
cultural‐specificbeliefsandattitudes.
Despitetheselimitations,itisclearthatvaccinationintentisinsomeway
linkedtoarangeofattitudesandbeliefs.Theimplicationforhealthpractitioners
isthatbehaviourintentmaybeopentoinfluencewherepsycho‐educationcan
createpro‐vaccineattitudesandbeliefs.Evenatthisearlystageitwouldbe
usefultoexposethisconclusiontoempiricaltestinginaninterventiondesign
thatteststheefficacyofspecifictypesofmessagesinchangingattitudesand
beliefsandifsuchchangeimpactsonvaccineintent.
22
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