Table Of ContentTaglionietal.BMCInfectiousDiseases2013,13:34
http://www.biomedcentral.com/1471-2334/13/34
RESEARCH ARTICLE Open Access
The influenza A (H1N1) pandemic in Reunion
Island: knowledge, perceived risk and
precautionary behaviour
François Taglioni1,2*, Michel Cartoux1, Koussay Dellagi2,3, Cécile Dalban4, Adrian Fianu4, Fabrice Carrat5,6,7
and François Favier4
Abstract
Background: The effectiveness of preventive measures depends onprevailing attitudes and mindsets within a
population. Perceived risk is central to a shift in mindset and behaviour. The present study aims to investigate the
perceived severity,vulnerabilityand precautionary behaviour adopted inresponse to the influenza A (H1N1)
epidemic thatbroke out in2009 onReunion Island (IndianOcean).As no H1N1vaccinationwas availableat the
time, non-medical interventions appeared ofcrucial importance to the control of theepidemic.
Methods: A cross sectional survey was conductedin Reunion Island between November 2009 and April 2010
within 2monthsof thepassage of theinfluenza A (H1N1) epidemic wave. Individualcontacts representing 725
households (one contact per household) were interviewed by telephoneusing validatedquestionnaires on
perceived risks. Mean scores were calculated for perceived severity,vulnerability, efficacy of preventive measures
and precautionary behaviour. Univariateanalysis was applied to identify preventivemeasuresand attitudes and
multivariate analysis was used to study the determinants ofprecautionary behaviour.
Results: More than 95%of contactedpersons accepted to participate to the survey. Eighty seven percent of
respondents believed that prevention was possible.On average, three out ofsix preventive measures were deemed
effective. Spontaneously, 57%of the respondents reported that they took one or more preventive measures. This
percentage increased to 87% after theinterviewerdetailed possible precautions one by one.The main precautions
taken were frequent hand washing (59%) and avoidance ofcrowded places(34%). In multivariate logistic regression
analysis the following factors were significantly associated with taking one or more preventive measures: young
age, previous vaccination against seasonal influenza, having had seasonal influenza in the last five years,
effectiveness of thepreventivemeasurestaken and low standardsofeducation.
(Continuedonnextpage)
*Correspondence:[email protected]
1UniversityofReunionIsland,BP7151,Saint-Deniscedex9,ReunionIsland
97715,France
2CentrederechercheetdeVeillesurlesMaladiesEmergentesdansl’Océan
Indien(CRVOI).PlateformedeRechercheCYROI,2RuemaximeRivière,
Sainte-ClotildeCedex,ReunionIsland97491,France
Fulllistofauthorinformationisavailableattheendofthearticle
©2013Taglionietal.;licenseeBioMedCentralLtd.ThisisanOpenAccessarticledistributedunderthetermsoftheCreative
CommonsAttributionLicense(http://creativecommons.org/licenses/by/2.0),whichpermitsunrestricteduse,distribution,and
reproductioninanymedium,providedtheoriginalworkisproperlycited.
Taglionietal.BMCInfectiousDiseases2013,13:34 Page2of12
http://www.biomedcentral.com/1471-2334/13/34
(Continuedfrompreviouspage)
Conclusion: Inhabitants of Reunion Island have expressed a preventiveapproach adapted to therealities of the
H1N1pandemic,a feature that likely reflects some preparedness gained after thelarge and severe chikungunya
epidemic thathit theisland in2006. The degree ofseverity was well assessed despitethe initial alarmist messages
disseminated by national and international media. Precautions thatwere undertakenmatched the degree of
severity of theepidemic and therecommendations issued by health authorities. Further qualitative studies are
needed to helpadaptingpublic messages to thesocial and cultural realities ofdiverse communitiesand to prevent
misconceptions.
Keywords: Influenza A (H1N1) pandemic, Knowledge, Perceived risk, Perceived vulnerability, Precautionary
behaviour
Background 45.2%(allages)andat63.2%,39.4%,16.7%inthe<20years,
Compliance with preventive measures, e.g. non-medical 20–59 years and ≥60 years old respectively [16]. During
action, is dependent on the attitude and willingness of the outbreak, 14 death certificates reporting influenza-like
thepopulation andonthespecific actions recommended illness were reported to the island’s public health author-
by health authorities [1-3]. Precautionary behaviour ities. The 2009 pandemic influenza A (H1N1) had no de-
results from a combination of social and psychological tectableimpactontheoverallmortalityonReunionIsland
factors such as personal values, socio-economic status since no excess of mortality was observed during the out-
and cultural background, gender, education, knowledge, break[17].
and beliefs about the disease, including perceived risks The context in which the Reunion Island population
and perceived effectiveness of the proposed action [2] waschallenged bytheH1N1pandemicisworthconsider-
[4-6]. These factors may be specific to each target popu- ing: In 2005–2006, an epidemic of chikungunya, a vector
lation and should be investigated to develop a locally borneinfectious diseaseduetoanalphavirus transmitted
adapted approach [7,8]. Understanding perceptions and by the mosquito Aedes Albopictus, originated from the
reactions among the general public during pandemics EastAfricancoastanddiffusedinalltheIndianOceanre-
may improve information and communication about gion. The epidemic had a major public health impact in
health risks and help shifting attitudes among the gen- Reunion Island (over one third of the population was
eralpublic [9-11]. infected) [18] and received extensive media coverage [19].
TheoutbreakofanewinfluenzaA(H1N1)virusstarted Asaresultofthe chikungunyaepidemic,ReunionIsland’s
in Mexico and the United States at the end of April 2009 population has been sensitized and prepared to the dan-
and quickly spread to other countries. On 11 June 2009 gersassociatedwithemergingepidemicdiseases.
theWorldHealthOrganization(WHO)declaredaglobal At the time the epidemic started in Reunion Island
influenza A (H1N1) pandemic, thereby raising major (July 21, 2009) no specific vaccine against the H1N1
internationalconcernovertheriskofhighmorbidityand virus was available (the vaccine became available in
mortality[12].Some14,000deathsrelatedtoinfluenzaA November, 2009). Hence health authorities had turned
(H1N1) were reported worldwide in the period up to their attention to non-medical measures recognized as
January,2010[13]. having an impact on infection transmission and mortal-
Reunion Island is a subtropical overseas French Island ity rates [20]. Alocal campaign emphasized regular hand
in the southern hemisphere, in the S.W. Indian Ocean, washing and avoidance of contact with diseased persons.
lying 700 km east of Madagascar and 200 km S.W. of Theyrecommended coveringthemouthand nosewith a
Mauritius. The Reunion Island population of 810.000 is paper tissue and wearing a mask if infected. The general
composed with communities from various ethnic origins public was encouraged to consult a doctor as soon as
(European, African, Asian) [14]. The first case due to in- symptoms of respiratory infection appeared and to stay
fluenza A (H1N1) virus was detected in a traveler return- athomeandtake individual protective measures [17].
ing from Australia on July 5, 2009 [15]. The first The present study aimed to investigate perceived risks,
autochthonouscasewasreportedonJuly21,2009andthe concern, behavioural responses and other key determi-
influenza A (H1N1) epidemic broke out during the nor- nants of precautionary behaviour related to the outbreak
mal period of seasonal influenzaie; austral winter. Hence, of the influenza A (H1N1) in Reunion Island. This was
theoutbreakstartedonweek30(July20),peakedonweek done in the frame of a research programme called
35 (August 28) and lasted until week 38 (September 20). CoPanFlu-RUN that included three complementary com-
A serological survey conducted on Reunion Island esti- ponents of epidemiological, virological and social science
mated the seroconversion rates to the pandemic virus at aspects.Theepidemiologicalandvirologicalparametersof
Taglionietal.BMCInfectiousDiseases2013,13:34 Page3of12
http://www.biomedcentral.com/1471-2334/13/34
the epidemy were assessed in a prospective study con- knowledge of airborne (saliva andsneezing) and contact-
ductedfromJuly21toDecember23,2009duringtheout- based (hands or objects) viral transmission modes was
break of influenza A (H1N1) [16,21,22]. Shortly after deduced from responses to the question: “What are the
passage of the epidemic wave, the social science aspects modes of transmission of influenza A (H1N1)?”. Two
werespecificallyinvestigatedinacross-sectionalstudy. otherquestionssuggestingerroneousmodesoftransmis-
sionwereasked(eatingporkmeat;stungbymosquitoes).
Methods Regarding antecedents (infection and vaccination), the
Participantsandsample questionnaire included a question on whether the re-
Following the H1N1 outbreak, a cross-sectional tele- spondent was vaccinated against seasonal influenza in
phonesurvey was conducted between November9, 2009 the last year and whether he or she had suffered from
and April 12, 2010 on perceived risks and precautionary seasonal influenzawithin thelastfive years.
behavior of Reunion Island inhabitants. The minimum Several questions tried to assess the perceived severity
sample size was estimated to 474 adults, assuming that of influenza A (a person’s belief of how serious contract-
30% of individuals were taking precautionary behaviour, ing the illness would be for him/her). Three questions
and considering 1% absolute precision and 5% p-value. were related to the pathology itself: “do you think influ-
The participants who accepted to participate to the cross enza A is more severe than seasonal influenza?”; “do you
sectional survey were recruited from the cohort investi- think influenza A is a fatal disease?”; “is there no effi-
gated by the CoPanFlu-RUN prospective study [16]. This cient treatment against influenza A?”. Another question
original cohort was composed of 762 households (2164 was asked in order to quantify the perceived severity.
inhabitants) (for details on the original cohort see [16,3]). This question “if you were to get infected with influenza
Participants in the described studyweretold thatthe sur- A, how serious a health issue would it be for you?”
vey focused on the outbreak of influenza A (H1N1) and resulting in a score of perceived severity on a scale of 0
theirinformedwrittenconsentwasrequired. to 10. Moreover, a general question addressed the im-
The questionnaire was administrated on a household pact on public health of influenza A (H1N1) among the
basis. One household’s reference person was identified population (percentage of the population infected by in-
among the three oldest members of each household. If fluenzaA(H1N1),number ofdeaths).
therewereaseniorcoupleinthehousehold,thereference The question: “how likely are you to get infected with
personwasalwaysthemaleparent.Iftherewasnocouple influenza A (H1N1)?” gave a score of perceived vulner-
in the household, the reference person was the oldest ability of influenza A (H1N1) on a scale of 0 to 10. The
non-dependent (male or female) person (source: French perceivedvulnerabilityofinfluenzaA(H1N1)isaperson’s
nationalinstituteforstatisticsandeconomicalstudies). perceptionofthechancethathe/shewillcontractthedis-
ease. A similar question to assess the vulnerability of sea-
Questionnaire sonalflugaveascoreofperceivedvulnerabilityofseasonal
Thequestionnaireusedinthisstudyhadalreadybeenvali- flu on a scale of 0 to 10. Also, a list of twelve potential
dated in a previous research protocol [23]. The question- risksordangersquotedbythemediaorpresentintheen-
nairewasbasedonanintegratedmodeldesignedtoexplain vironment (GMO, cell phones, cyclones, global warming,
precautionary behaviour, including constructs drawn from chikungunya, air pollution, car accidents, smoking, pesti-
the Protection Motivation Theory (PMT) [24] and Health cidesinfood,diabetes,AIDS,cancer)wasproposedbythe
Belief Model (HBM) [25]. The survey about influenza A interviewersandtherespondentshadtorankforeachpo-
(H1N1) outbreaks included a wide range of questions tential risk their concerns with regard to these risks on a
related to levels of knowledge, antecedents (infection and scaleof0to10.
vaccination), perceived risks (including perceived severity Response efficacy (a person’s belief in the effectiveness
and perceived vulnerability), response efficacy, perceived of the preventive measure) was evaluated by the inter-
self-efficacyandprecautionarybehaviour. viewer with two questions. Firstlyageneralquestionwith
Regarding knowledge of clinical signs and modes of adichotomousanswer(yesorno)wasasked“arethereef-
transmission,scalesof0to6werecompiledbasedonthe fective preventive measures to protect you from influenza
numberofpositiveresponses,resultinginmeanscoresof A(H1N1)?”.Secondly,alistofsixrecommendedinfluenza
symptom knowledge. Firstly, a score reflecting know- A (H1N1) prevention measures was read (washing hands
ledge of the four major symptoms that are frequently morefrequently,gettingvaccinatedagainstseasonalinflu-
encountered in mild influenza (fever, headaches, aches enza, wearing masks in public, avoiding public transport,
andpains,runningnose)andmorespecificallyinrespira- avoiding crowed places, not sending children to school).
tory complications (coughing and dyspnea) was deduced Thequestionwas“whichpreventivemeasuresamongthis
fromresponsestothequestion:“Whatarethesymptoms listyouthinkareeffectiveatkeepingyoufromgettingthe
of influenza A (H1N1)?”. Secondly, a score estimating influenzaA(H1N1)?”.Theeffectivenessofeachpreventive
Taglionietal.BMCInfectiousDiseases2013,13:34 Page4of12
http://www.biomedcentral.com/1471-2334/13/34
measure had been ascertained separately. Furthermore, Ethicalconsiderations
precautions regarded as effective by each individual pro- Thequestionnairewasconductedinaccordancewiththe
duceda scorefortheeffectivenessofpreventivemeasures Declaration of Helsinki and French law for biomedical
from0to6. research (Nu ID RCB AFSSAPS: 2009-A00689-48) and
Perceived self-efficacy (a person’s level of confidence in was approved by the relevant Ethics Committee (Comité
his/her ability to perform the preventive measure) was de Protection des Personnes of Bordeaux 2 University).
assessed by asking a question with a dichotomous answer Persons eligible for participation were asked to give their
(sureornotsure)“howsureareyouthatyoucanbyyour- written,informedconsent.
selfpreventgettingtheinfluenzaA(H1N1)?”.
During the interview, respondents were first asked Results
whether they had taken precautions to avoid influenza Socio-demographiccharacteristicsandinfluenzalike
during the epidemic. Allresponseswererecorded,includ- illness
ingthosewhichdidnotcorrespondtoofficialrecommen- Among the 762 households constituting the original
dations from health authority or mistaken responses. In a CoPanFlu-RUN sample that were contacted by tele-
second, more directive phase, six types of precautions phone, individuals representing 725 households accepted
(washing hands more frequently, getting vaccinated to take part in the survey, giving a participation rate of
againstseasonalinfluenza,wearingmasksinpublic,avoid- 95%. Therewasamajorityofwomen(73%)(versus52%in
ing public transport, avoiding crowed places, not sending thegeneralReunionislandpopulation)a.Oursamplecom-
children to school) were mentioned one by one by the prised alsoamajorityofelderlypeople,48%over60years
interviewer. Respondents were asked whether they had olds (versus 17% in general Reunion island population)a.
taken measures to prevent them getting infected with in- Onethirdofrespondentshadgraduatedfromhighschool
fluenza A (H1N1). Respectively, two scores of preventive and/orwereinhighereducation(Table1).
measures, taken immediately and after detailed review Over one third of the respondents (36%) stated that
withinterviewer,wereimplementedonascaleof0to6. they had had influenza like illness during the epidemic
of 2009 (Table 1). Two thirds (68%) declared that they
Statisticalanalysis hadhadseasonalinfluenzainthelastfiveyears(Table1).
Data entry used EpiData version 3.1 (The Epidata Associ- Vaccination against seasonal influenza was reported by
ation,Odense,Denmark).SASversion9.1(SASInc.,Cary, 25% of all participants (Table 1), and by 40% of people
NC,USA)wasusedforstatisticalanalysis.Tostudycorre- aged60andover.
lates of precautionary behaviour, a new dichotomous vari- Theyoungestrespondents(18–59years)declaredhaving
able “precautionary behaviour” was defined and coded 1 had influenza like illness more frequently than elderly
(yes), if respondents had taken one or more preventive people (43% versus 30%, p < 0.001)a. The proportion of
measures,andcoded0(no)ifrespondentshaddonenoth- individuals declaring influenza like illness declined with
ing.Univariateandmultivariatelogisticregressionanalyses ageasfollows:53%in18–29yearolds,43%(30–44years),
were performed to identify factors significantly associated 34% (45–59 years) and 30% (≥60 years)a. Fewer elderly
with taking one or more preventive measures. For uni- people stated they had had influenza like illness in the
variate analysis, demographics, knowledge, antecedents last five years compared with the younger respondents
(infection and vaccination) perceived severity, perceived (p<0.001).Elderlypeoplewerealsomorefrequentlyvac-
vulnerability, response efficacy and perceived self-efficacy cinated(p<0.001)a.
wereenteredaspredictorvariables.
First a univariate analysis was performed using chi- Knowledgeofthesymptomsandmodesoftransmission
squaredtestsorFisher’sexacttestsforcategoricalvariables On the average, knowledge of influenza A (H1N1) symp-
and Student’s t-test for normally distributed continuous toms scored 2.35 (SD 1.29) on a scale of 0 to 6 (Table 2).
data; non-parametric tests (Mann–Whitney) were used if Eighty seven percent of respondents reported at least one
appropriate. Univariate analyses were performed with self- correct symptoma. The majority of the respondents (78%)
reported characteristics as independent variables and tak- felt that they had been well informed about influenza A
ingprecautionarybehaviourasthedependentvariable.For (H1N1)a. Main symptoms identified by respondents were
the odds ratios, 95% confidence intervals (CI) were calcu- (in decreasing order of frequency): fever (79%), aches and
lated. Second, for the multivariate regression analyses, all pains (53%), headaches (36%) and a running nose (25%)a.
factors with a p-value <0.2 in the univariate analysis were Symptoms morespecificallyrelatedtotherespiratorysys-
enteredinthemultivariatemodel.Thepotentialconfound- tem andmore suggestive ofseverity, (coughand dyspnea)
ing factors (age) were included in our multivariate model. wereidentifiedlessfrequently;33%and9.5%respectivelya.
This model was fitted with a step-to-step backward The score of positive responses to modes of transmis-
elimination. sion was 4.47 (SD 1.38) on a scale of 0 to 6 (Table 2).
Taglionietal.BMCInfectiousDiseases2013,13:34 Page5of12
http://www.biomedcentral.com/1471-2334/13/34
Table1Distributionofgeneralcharacteristicsinthestudypopulation
N %
Overallsample 725 100%
Socio-demographiccharacteristics
Sex
Male 192 27%
Female 533 73%
Age
18-29years 53 7%
30-44years 237 33%
45-59years 91 12%
60+years 344 48%
Educationallevel
Highschoolgraduateorhighereducationallevel 214 30%
Nothighschoolgraduate 511 70%
Influenza:infection,vaccinationandantecedents
Infectedwithinfluenzaduringtheoutbreak2009
No 462 64%
Yes 263 36%
Infectedwithseasonalinfluenzaduringthepastfiveyears
No 231 32%
Yes 494 68%
Vaccinatedagainstseasonalinfluenza
No 543 75%
Yes 182 25%
Among respondents, 90% and 80% werefamiliar withair- 5.31, p = 0.001)a and vulnerability scores (5.70 versus
borne transmission (saliva, sputter and cough) and with 4.72, p < 0.001)a were significantly higher than among
transmission through contact (hands or objects) respecti- men. This trend was also observed with the dichotom-
velya. Erroneous modes of transmission were mentioned ous question on perceived severity (60% versus 51%, OR
by43%ofrespondentsa.Forexample, 9% mentionedpork 1.4, p = 0.03) and for the estimated proportion of indivi-
meat as a potential mode of transmission while 40% re- duals infected by influenza A (H1N1) (means of 33.20
ferredtothemosquitoa. versus 21.15, p < 0.001)a. However, these risk perception
indicatorsdidnot varywith age.
Perceivedseverityandvulnerability Compared to other concerns, influenza A (H1N1) was
Perceivedseverityscored6.05(SD3.05)whereasperceived not considered as a major cause for concern (level of con-
vulnerability scored 5.26 (SD 3.67) on a scale of 0 to 10 cern 5.3). In terms of epidemic severity, the chikungunya
(Table 2). Perceived severity observed by score was rein- virus raised more concern than the influenza A (H1N1)
forced by the dichotomous question (“do you think influ- (levelofconcern7.1).Themainhealthconcernissueswere,
enza A is more severe than seasonal influenza?”). Indeed, in decreasing order: cancer, AIDS and diabetes (between
a majority (58%) perceived influenza A (H1N1) as more 7.6to8.0onascaleof0to10)(Figure1).
severe than seasonal influenzaa. Moreover, influenza A
(H1N1) was regarded as being untreatable by 46% of the
respondents and as fatal by 42%a. Respondents felt that Effectivenessofpreventivemeasures
30%oftheReunionIsland’spopulationwasinfectedbyin- The effectiveness of preventive measures (response effi-
fluenza A (H1N1)a and that approximately twenty people cacy) scored 3.04 (SD 1.57) on a scale of 0 to 6 and was
haddiedofinfluenzaA(H1N1). higher among those who took precautions (3.15 versus
Perceived severity, perceived vulnerability and esti- 2.30, p < 0.001) (Table 2). This result by score was rein-
mated proportion of individuals infected by influenza forced by most respondents (82%)a who regarded preven-
differ by sex. Among women, severity score (6.32 versus tion as possible. Similarly, 83% of respondents felt that it
Taglionietal.BMCInfectiousDiseases2013,13:34 Page6of12
http://www.biomedcentral.com/1471-2334/13/34
Table2Scoreofknowledge;perceivedseverity;perceivedvulnerability;precautionarybehaviourtaken
2.1Knowledgeofsymptomsandtransmissionmodes(scale0–6)
Takingoneormorepreventivemeasures
(n=725) (n=633) (n=92)
Overall Yes No p-value
Scoreofsymptomknowledge
Mean 2.35 2.35 2.30 0.52
SD 1.29 1.31 1.19
Median 2 2 2
Scoreforknowledgeofmodesoftransmission
Mean 4.47 4.50 4.30 0.324
SD 1.38 1.36 1.52
Median 5 5 4.5
2.2Perceivedseverity,vulnerability(scale0–10)
Takingoneormorepreventivemeasures
(n=725) (n=633) (n=92)
Overall Yes No p-value
Scoreofperceivedseverity
Mean 6.05 6.14 5.40 0.017
SD 3.05 3.03 3.18
Median 7 7 7
Scoreofperceivedvulnerability
Mean 5.26 5.43 4.10 0.001
SD 3.67 3.65 3.64
Median 7 7 3.5
2.3Effectivenessofpreventivemeasures(scale0–6)
Takingoneormorepreventivemeasures
(n=725)
Overall
Scorefortheeffectivenessofpreventivemeasures
Mean 3.04 3.15 2.30 <0.001
SD 1.57 1.55 1.53
Median 3 3 2
was possible to reduce the risk of infection through indi- they had taken (immediately and after listing all the pre-
vidualpreventiveaction(perceivedself-efficacy)a. cautions). Hand washing more was the precaution that
the respondents considered as the most effective (95%)
Precautionstaken and appeared to also be the most implemented as a pre-
Precautionstakenscored 0.60(SD 0.67)ona scaleof0to ventive measure against A influenza: 46% spontaneously
6 and scored 2.02 (SD 1.19) when the interview reviewed replied that they had taken this precaution and 59% con-
the six availableprecautionsa. Themajorityoftherespon- firmed they had taken this precaution after it was recalled
dents(57%)declaredthat theyhadtakenatleastonepre- by the interviewer. Paradoxically, the wearing of masks, al-
caution against influenza A (H1N1)a. This percentage thoughbetterperceivedintermsofefficacythanavoidance
increased to 87% after the interviewer detailed possible behaviour, was not widespread (9%). Vaccination against
precautions one by onea. The two main precautions that seasonalinfluenzawasconsideredaseffective(37%)though
therespondentsstatedtheytook,regardlessofthemethod itwaslessused(14%)topreventinfluenzaA(H1N1).
of questioning, were: more frequent hand washing and Aunivariateanalysisrevealedthateight significantfac-
avoidanceofmixingingroups(Figure2). tors contributed to the precautions taken against influ-
Figure2combinesforeachrecognizedlevelofefficacy, enza A (H1N1): 1) being a female (Table 3), 2) having
the percentage of precautions that the respondents said been vaccinated against seasonal influenza (Table 3),
Taglionietal.BMCInfectiousDiseases2013,13:34 Page7of12
http://www.biomedcentral.com/1471-2334/13/34
Average
10
9 7,6 7,9 8,0
8 6,8 7,1 7,2 7,2 7,3 7,4
7 5,6 5,6 6,2
6 5,3
5 4,5
4
3
2
1
0
Figure1Concernsratedonascaleof0to10(n=725).
3) havinghadinfluenzainthelastfiveyears(Table3),4)a Discussion
higher perceived severity (Table 3), a higher score of Manyrespondentsstatedthattheyhadtakenprecautions:
perceived severity (Table 2), 5) a higher scoreof perceived 87%didsoaftertheinterviewerhaddetailedpossiblepre-
vulnerability (Table 2), 6) a higher response efficacy cautions one by one. When possible precautionary mea-
(Table 3), 7) a higher perceived self efficacy (Table 3), 8) a sures were listed by the interviewer, “precautions taken”
higher score for the effectiveness of preventive measures scored 2.02 reflecting that precautionary behaviour, albeit
(Table2). frequent, focuses on a small number of preventive mea-
Table 4 shows the results of the multivariate analysis. sures taken at a single time. Whatever the way of asking
Factors associated with taking one or more preventive the question, the main precautions that the respondents
measures were: 1) young age; 2) having been vaccinated stated they had taken (hand washing and avoiding
againstseasonalinfluenza;3)havinghadseasonalinfluenza crowded places) were in agreement with official recom-
in the last five years; 4) a higher number of preventive mendations[26].Inseveralsurveys,handwashingwasthe
measures regarded as effective; 5) low standards of educa- mainprecaution thatthe respondents said theyhad taken
tion. Being young adults (i.e. aged 18 to 29) increased the [4,27]. This precaution was taken to the same extent on
adoptionofprecautionaryactionbyafactor8. ReunionIsland(59%)andinFrance(59.7%)buttoalesser
Found effective
Taken after detailled review
Declared taken immediatly
100% 95%
90%
80%
70%
59% 61%
60%
46% 50%
50%
38% 37%
40% 34% 31%
24%
30%
19%
20% 14%
9% 9%
10% 4%
0% 0% 0%
0%
More frequent Wear mask Avoid crowds Avoid public Be vaccinated Do not send
washing of transport against children to
hands seasonal flu school
Figure2PreventivemeasurestakenandfoundeffectiveagainsttheH1N1virus(n=725).
Taglionietal.BMCInfectiousDiseases2013,13:34 Page8of12
http://www.biomedcentral.com/1471-2334/13/34
Table3Proportionsofrespondentsthatreportedtohavetakenoneormorepreventivemeasuresandresultsfrom
univariateanalysis
N % OR 95%CI p-value
Overallsample 725 87%
3.1Socio-demographiccharacteristics
Sex
Male 192 83% 1.00 0.028
Female 533 89% 1.67 1.02–2.71
Age
18–29years 53 98% 1.00 0.423
30–44years 237 85% 1.31 0.81–2.11
45–59years 91 86% 1.70 0.59–2.28
60+years 344 88% 0.97 0.61–1.53
Educationallevel
Highschoolgraduateorhighereducationallevel 214 84% 1.00 0.094
Nothighschoolgraduate 511 89% 1.40 0.90–2.30
3.2Influenza:infection,vaccinationandantecedents
Infectedwithinfluenzaduringtheoutbreak2009
No 462 86% 1.00 0.139
Yes 263 90% 1.43 0.87–2.30
Vaccinatedagainstseasonalinfluenza
No 543 85% 1.00 <0.001
Yes 182 96% 3.98 1.88–8.39
Infectedwithseasonalinfluenzaduringthepastfiveyears
No 231 82% 1.00 0.002
Yes 494 90% 1.97 1.26–3.07
3.3Perceivedseverity
InfluenzaAismoreseverethanseasonalinfluenza
No 305 84% 1.00 0.023
Yes 420 90% 1.65 1.06–2.56
InfluenzaAisafataldisease
No 423 84% 1.00 0.005
Yes 302 91% 1.96 1.21–3.17
ThereisnoefficienttreatmentagainstinfluenzaA
No 395 90% 1.00 0.023
Yes 330 84% 0.60 0.38–0.96
3.4Responseefficacy,perceivedselfefficacy
Responseefficacy
No 131 79% 1.00 0.001
Yes 594 89% 2.18 1.33–3.59
Perceivedselfefficacy
No 124 82% 1.00 0.035
Yes 601 89% 1.73 1.03–2.91
degree in the Netherlands (36%). Avoiding gatherings as being the most active in terms of prevention, in con-
(crowded places) was mentioned more often by the trast to other studies which reported elderly people to
respondents on Reunion Island (34%) than in France be more active in applying preventive measures [5,28,29].
(14.6%)[27]ortheNetherlands(8%)[4]. Young adults were 8 times more likely to undertake pre-
The specific behaviour of young adults is an important ventivemeasuresthanotheragegroups.Atthesametime,
result of our study. Young adults (18–29 years) appeared the proportion of the population reporting influenza like
Taglionietal.BMCInfectiousDiseases2013,13:34 Page9of12
http://www.biomedcentral.com/1471-2334/13/34
Table4Multivariatelogisticregressionanalysis: link between mosquito and influenza A (H1N1). Finally, a
predictorsoftakingoneormorepreventivemeasures question remained as to the transmission of the infection
amongsixlistedprecautions from pigs topeople. In fact the zoonotic transmission was
OR 95% CI p-value exactlytheoppositeinReunionIslandandwasthatofare-
Agegroup verse zoonosis (ie: transmission of the virus from humans
18-29years 7.90 1.01 16.58 0.04 to animal) as large and prolonged contamination of swine
herds in Reunion Island occurred as a consequence of the
30-59years 0.87 0.52 1.47 0.62
H1N1pandemic[30].
60+ 1.00
In our study, multivariate analysis showed that vaccin-
Vaccinatedagainstseasonalinfluenza
ationagainstseasonalinfluenzaappearedrelatedtoamore
Yes 4.44 2.00 9.86 <0.001
general preventive attitude, as has also been observed in
No 1.00
other studies [31]. This suggests that seasonal vaccination
Infectedwithseasonalinfluenzainthepastfiveyears applied before the start of the epidemic, as an initial step
Yes 1.84 1.12 3.00 0.02 towards prevention, had promoted preventive behaviour
No 1.00 during theepidemic. Similarlya previous study hasshown
Scoreforeffectivenessofprecautionarymeasures(scale0–6) that undertaking influenza vaccination in the past, greatly
1.51 1.27 1.79 <0.001 facilitatesvaccinationinsubsequentyears[32].Vaccination
1.00 against seasonal influenza was not part of the recommen-
dationsagainstinfluenzaA(H1N1)andnospecificvaccine
Educationallevel
againstinfluenzaA(H1N1)wasavailableduringthewhole
Highschoolormore 0.57 0.33 1.00 0.05
H1N1 outbreak in Reunion Island. Nevertheless, 37% of
Nothighschoolgraduate 1.00
respondents,regardlessoftheirage,believedintheefficacy
of the vaccine against seasonal influenza and 14% stated
that they had taken this precaution to protect them from
illnessinoursamplewashigheramongyoungpeopleand influenza A (H1N1). This attitude fitted the logic of previ-
decreased with age. This feature was in agreement with ousmessages:avaccinethatincludesstrainsthatcirculated
results of the virological survey conducted on the same in previous years is also supposed to provide a protection
population in the context of the CoPanFlu prospective (evenpartial)againstthenewlyintroducedstrain.Thiswas
study that revealed that young people had been far more what transpired during the epidemic [16]. Vaccination
frequently infected by influenza A (H1N1) than elderly against seasonal influenza was more widely adopted in
respondents [16]. One interpretation might be that young main France than in the overseas department of Reunion
adultscouldhavereactedwelloncetheyrealizedthatthey Island(25.6%versus14%).Ofnote,however,isthefactthat
weremoreexposedtoinfluenza A(H1N1)thanotherage in France, where the specific vaccine against influenza A
groups. The research into behavioural attitudes over an (H1N1) wasavailable, the useof thenew vaccinewas lim-
extended period during influenza epidemics shows that itedwithacoverageofonly27.4%[25].
people are highly adaptive and that their attitudes evolve The number of preventive measures regarded as ef-
overtime[4,5]. fective scored 3.04 (on a scale of 0 to 6), confirming
Moreover, the most educated respondents had likely good knowledge of preventive measures and confidence
adjusted their behaviour to the changing general belief in the precautions suggested in the local prevention
about the real severity of the epidemic. Those people campaigns. The score for the effectiveness of preventive
most informed about the projected lower severity of the measures remained a predictor of precautionary behav-
epidemic, felt it less necessary to take effective precau- iour in the model. The optimism through belief in a
tions.Conversely,alowstandardofeducation wasfound large number of precautions regarded as effective was
to be associated with precautionary behaviour in our also shown in another study conducted in the United
study as in a similar study conducted in the Netherlands Kingdom [2].
duringahuman avian influenzaepidemic[5]. Perceived severity and vulnerability with regard to in-
Thevastmajorityofrespondentssaidthattheywerewell fluenza A (H1N1) were regarded as moderate with aver-
informed(78%)andshowedthattheywereknowledgeable. age scores of 6.05 and 5.26 respectively (on a scale of 0
Knowledge of modes of transmission scored a satisfactory to 10). As our survey was conducted after passage of the
4.47 (on a scale of 0 to 6) especially since for each wrong epidemic wave, the perception of risk and severity of in-
answer one point was deducted from the total score. This fluenza A (H1N1) might have been minimized. A previ-
was true for 40% of the respondents who mentioned the ous survey conducted in three phases over the course of
mosquitoasapotentialvectoroftransmission. Therecent an epidemic showed that perceived severity decreased at
chikungunya epidemic in Reunion Island may explain this the end of the epidemic [4]. However, these perceptions
Taglionietal.BMCInfectiousDiseases2013,13:34 Page10of12
http://www.biomedcentral.com/1471-2334/13/34
remain higher on Reunion Island than in France where Ourstudyhasanumberoflimitations.Firstly,oursam-
perceived severity and vulnerability were on average 3.64 ple was not representative of Reunion Island’s population
and 2.95 respectively [27]. Finally, the severity of influ- duetotheinclusionofahighproportionofelderlypeople
enza A (H1N1), although rated as moderate, may have andwomen.Hencewhetherconclusionscouldbegeneral-
been slightly overestimated by our sample owing to the ized to the whole population of Reunion Island may be
fact that it contained a large proportion of women whose questionable. The over-represented elderly people and
perceived severity and perceived vulnerability were women weigh towards a selection bias. An explanation is
observed to be higher. This finding is shared by other that the interviewers preferred home-based respondents,
studies [5,33]. Influenza A (H1N1) was regarded as more thereby limiting refusals but making the choice of the
serious than seasonal influenza by most of the respon- household’s reference person more difficult. Analysis by
dents (58%) but did not cause major worries compared sex and age group do not reveal significant statistical dif-
to other concerns. Health concerns focused on chronic ferencesexceptahigherperceptionofseveritybywomen.
diseases;cancerwasthemainconcernoftherespondents, However, selection bias (women and elderly over-
as had been observed in a previous study in France [33]. represented) hassimplyrevealed,inthemultivariateana-
Moreover, influenza A was presented in the media as a lysis, the contrasted attitude of young people. Apart from
serious epidemic, meaning that a parallel could havebeen thisresult,elderlypeopledidnotappeartohaveaparticu-
drawn with the unquestionably more severe vector born lar attitude. Elderly people could have overestimated se-
Chikungunya epidemic. This potential danger was con- verity of influenza A (H1N1) because influenza is known
firmed by concern over a future chikungunya epidemic as an important cause of morbidity and mortality among
that scored 7.1 (on a scale of 0 to 10). The perceived risk elderly people [35]. However, our study did not reveal a
of influenza A (H1N1) on Reunion Island must be inter- higher perception ofthe risks among elderly respondents.
preted in the context of the previous chikungunya epi- Theelevatedtendencytowardsisolationamongourtarget
demic of 2006. Although this epidemic occurred three population does not seem related to the composition of
yearsbefore,itrapidlyspreadonalargescale,wasseverely oursamplealthoughelderlyrespondentsmaynaturallybe
symptomatic in a large fraction of the population (mus- more inclined towards isolation owing to their generally
cular and articular pain) and brought about chronic reduced mobility. However, the young and elderly people
symptoms in a significant proportion of infected per- in our sample declared that they taken this precaution to
sons (266,000 cases, 246 persons hospitalized in intensive an equal extent (avoidance of mixing in groups: crowds,
care, some40maternity-neonatalinfectionsand atotal of transport).
243 deaths) [19]. Comparatively, the influenza A (H1N1) A second limitation is that the survey started at least
epidemic was regarded as far less severe both in terms of 2.5 months after the outbreak and recall bias is a pos-
itsscaleanditshealthconsequences. siblelimitation.It seemshoweverthatthisbiaswasmiti-
Our study shares, with several other univariate analysis gated. As already mentioned, there is a good correlation
studies, three main factors influencing the adoption of between infected cases of influenza A (H1N1) among
precautionarybehaviour:perceivedseverity,perceivedvul- respondents and their serological status [16]. These ex-
nerability and perceived self-efficacy [2,4,5]. These results planatoryfactorsare consistent with alowrecallbias.
are in accordance with the Protection Motivation Theory Athirdlimitationmayarisefromtheintroductionofde-
(PMT) [24] and Health Belief Model (HBM) [25]. These sirability bias by the two-phase questioning technique
factors are not always retained following a multivariate used to assess the implementation of precautionary mea-
analysis since they are closely related to age, gender and sures. However, compared to self-reported precautions,
standard of education, all factors that are confusing in a the second method has allowed collecting more complete
multivariate analysis. The socio-demographic profiles of data. Indeed, the response rate is always higher when
the samples impact the model, revealing distinctive fea- memory is prompted by exhaustively recalling all the
turesspecifictoeachtargetpopulationtarget.Oursample availableprecautions.Ontheotherhand, therespondents
could have played this role, highlighting the contrast in very often mentioned first the active steps they had taken
behaviour between elderly and young adult respondents. individually (hand washing, wearingof a mask, being vac-
The research into behavioural attitudes over an extended cinated). The avoidance type precautions (not going to
period during influenza epidemics shows that such atti- concerts,nottravelingonpublictransport,nottakingchil-
tudesevolveovertimeandthatpeoplearehighlyadaptive dren to school) are retained more after a recall. It is pos-
[4,5]. The authors agree that such perceptions (severity, sible that the reported precautionary behaviors of young
vulnerability, perceived self-efficacy) are underpinned by adults could result from a social desirability bias as the
anxiety which is itself dependent on the messages con- participation of an interviewer can prompt responses
veyed by health authorities and which are in turn relayed reportingtheimplementationofpreventionmeasures.De-
bythemedia[2,4,5,34]. sirability bias is unlikely once the reality of the epidemic
