Perceptions towards the A/H1N1 vaccine among risk groups.

Transcription

1 Södertörns University Schl f Natural Sciences, Technlgy and Envirnmental Studies Master thesis 15 ECTS Infectius Disease Cntrl spring 2014 Perceptins twards the A/H1N1 vaccine amng risk grups. A study cnducted in Stckhlm, Sweden. By: William Raske Supervisr: Inger Prsch-Hällström

2 Table f Cntents 1. Intrductin Research Objective Research questin Previus Research Material and Methd Questinnaire Selectin and limitatins Data Cllectin Pre-pilt and Pilt study Validity and acceptability Reliability Respnse rate Methdlgical limitatins Data analysis Result Analysis Discussin Cnclusin References Appendix

3 Abstract Influenza type A is assciated with mst severe cmplicatins t humans and is histrically recgnized t cause pandemics. If a new subtype replicates well in humans it might upsurge in a new pandemic strain, ne such example is the Influenza A (A/H1N1). The A/H1N1 pandemic in 2009/2010 was nt as severe in Sweden as expected. Criticism has targeted the fact that authrities having misjudged the need fr vaccinatin, cncerns have been raised regarding the effect f the campaign n peple s willingness t be vaccinated in the future. This study aims t investigate if there are significant differences in attitudes twards the vaccinatin f A/H1N1 amng different ppulatin grups in Stckhlm, Sweden. The main grups explred are risk grups and nn- risk grups, defined by bjective definitins. A quantitative methd was apprached using questinnaires. The result indicates that peple in a risk grup and vaccinated had mre favrable attitudes twards the vaccine cmpared t ther grups. They als expressed less trubled cncerns regarding vaccine safety and were mre likely t immunize referring t inadequate health. It is evident that peple at risk als define themselves as mre vulnerable, in which vaccinatin is mre acceptable. The expressed attitudes are in such dependent n risk-perceptins and vaccine status. Keywrds: perceptins, A/H1N1, risk grup, nn-risk grup, vaccine and health preventins.

4 4 1. Intrductin The virus causing influenza can be categrized int three different grups, influenza type A is the ne assciated with mst severe cmplicatins t humans and is histrically recgnized t cause pandemics. Except the human hst, mst influenza A viruses circulate naturally amng rganisms. Sme f these viruses have crssed species barriers and have becme established in humans and pigs, resulting in the creatin f human influenza- and swine influenza viruses. Influenza type A viruses cntain eight segments f single-stranded RNA which cde fr ten prteins, their RNA plymerases is a lw-fidelity transcriptin enzyme lacking the prfreading functin ability f DNA plymerases, which means that their mutatin rate is high. The tw mst imprtant prteins are classified by the type f hemagglutinin and neuraminidase prteins which are present n the virus surface. The cmpsitins and variatins f these tw specific prteins cause the virus t transfrm int different subtypes, resulting in peridical epidemics f influenza (Nelsn & Williams, 2006). This ccurrence is ften referred t as antigenic drift and antigenic shift. Antigenic drift is the result f minr antigen changes thrugh spntaneus mutatins, any such change f epitpes makes the antibdy detectin f the virus much mre prblematic. The antigenic shift n the ther hand is the creatin prcess f a new subtype. In such case tw influenza viruses, human r animal, infect the same hst cell at the same time resulting in an exchange f genes and their genmes. Pigs are very likely t serve as a mixing vessel that may result in such a shift. Antigenic change f the influenza virus is cnstantly ccurring randmly in nature and if a new subtype replicates well in humans it might upsurge in a new pandemic strain, ne such example is the Influenza A (A/H1N1) (Gauci et al. 2010). The transmissin f the A/H1N1 influenza t humans ccur in the same way in which the seasnal influenza transmits, which is thrugh respiratry secretins frm an infected persn. These secretins are airbrne and spread via direct and/r indirect cntact. In practice, the transmissin f the virus is

5 5 caused by the actin f cughing, sneezing and cntact with cntaminated surface bjects (Centers fr Disease Cntrl and Preventin, 2010). In the beginning f 2009, spatial and tempral distant cases were identified by the surveillance systems mnitred by infectius disease cntrlling authrities in the Americas. The symptms were similar and the findings were reprted t the Wrld Health Organizatin (WHO). The case definitins amng ther included the symptms f febrile respiratry illnesses experienced by mainly yung and therwise healthy children. Initially it became evident that the patients were infected with a nvel swine flu virus. By the time the virus was islated it culd be scientifically prven that the virus riginated frm the same strain and that it replicated well in humans (Gauci et al. 2010). The evlvement f the disease tk even greater prprtins in the next upcming weeks f The inability t cntrl the disease was evident and by the time the epidemilgical status f the A/H1N1 was upgraded t the highest level, phase six, the A/H1N1 influenza had spread in mre than tw cntinents and reaching pandemic prprtins. By the encuragement f WHO vaccinatin prgrams were adapted as a respnd t the increased respnsibility n cuntry levels and the implementatins f prtective measurements (Gauci et al. 2010). In Sweden the implementatin f pandemic phase six status was met with a decisin t rder vaccine dses enugh t ffer immunizatin t its entire ppulatin. Initially, the aim was t target ppulatins f health care wrkers and individuals with underlying illnesses. The risk grups were (and are still) defined by the recmmendatin frm the Swedish Natinal Bard f Health and Welfare (Scialstyrelsen), as peple with risk f cmplicated curse f disease. This includes pregnant wmen, peple lder than six mnths f age with underlying illnesses r ther immune cmprmised cnditins and peple aged 65 (Scialstyrelsen, 2009). In Sweden, the mass vaccinatin campaign against the influenza A/H1N1 in 2009/2010 resulted in a 60 percent vaccinatin cverage which is described

6 6 as a successful interventin. Hwever, many cuntries had difficulties in mtivating citizens t get vaccinated (Scialstyrelsen, 2011). Accrding t the Wrld Health Organizatin (2010) the pandemic phase was fficially ver in August The labratry cnfirmed death cases were glbally estimated t mre than It was acknwledged that the majrity f peple experienced the mst serve illness cnditins ccurred amng yung adults. In retrspect, the pandemic ccurrence in 2009/2010 was nt as sever in Sweden as expected. Criticism has targeted the fact that authrities having misjudged the need fr vaccinatin. Furthermre, cncerns have been raised regarding the effect f the campaign n peple s willingness t be vaccinated in the future, if a new and severe pandemic ccurs (Börjessn & Enander, 2013). It can further be argued that the mass vaccinatin prgram, which was the main preventin measurement against A/H1N1, was met with a lt f public attentin and criticism. The reprting media was a majr actr in shaping peple s pinins in Sweden and even thugh the lw mrtality rates was explained by the successful vaccinatin campaign, the discussin and cmparisns with cuntries (e.g. Germany) which experienced lw vaccinatin cverage and lw mrtality rates was nnexistence. The further intensive discussins regarding the safety and sideeffects f the vaccine in the mainstream media cntinued t cnfuse the public (Odén, 2010). As utlined by Steelfisher et al. (2010) in the event f a future pandemic, a substantial prprtin f the public may nt take a newly develped vaccine, because they may believe that the illness des nt pse a serius health threat. Mrever, additinal cncerns abut the safety f the vaccine may dminate their actins, meaning mre research shuld aim t address these beliefs.

7 7 2. Research Objective Vaccinatin is critical in rder t cntrl infectius disease transmissin during a pandemic (Scialstyrelsen, 2009). Yet little is knwn abut hw the ppulatin at risk perceives the nging change f attitudes twards vaccinatin against A/H1N1. Since several researchers have bserved a negative apprach amng the general ppulatin twards the willingness t be immunized, serius threats are psed n future health interventins (Peretti-Watel et al. 2013; Walter et al. 2012; Björkman & Sanner, 2012; Seale et al. 2010; Rachitis et al. 2010). This study s intentin is t evaluate if there is a difference between attitudes amng different grups. The tw grups, which will be cmpared, are defined as an experimental grup; which is at risk f experience cmplicated utcmes f the influenza (risk grup) and ne cntrl grup that is nt (nn-risk grup). The inclusin criteria t define the grups are based n bjective definitins fllwing the recmmendatin frm Swedish authrities and can be fund n page five. The independent explanatry variables (X) will in this case meet the criteria t define peple as a risk grup and will be used t explain variatins f the dependent respnse variables (Y). 2.1 Research questin The aim f this thesis is t: - Investigate if there are significant differences in attitudes and perceptin twards the vaccinatin f A/H1N1 amng different ppulatin grups in Stckhlm, Sweden. The null hypthesis (H 0 ) tested is in such: there are n differences f attitudes twards vaccinatin f A/H1N1 between peple defined as risk grup and peple nt being defined as risk grup. The alternative hypthesis (H 1 ) is that there are differences amng these grups.

8 8 3. Previus Research A number f previus researches have addressed factrs assciated with the attitudes twards the A/H1N1 vaccine. In a recent study cnducted by Peretti-Watel et al. (2013) the researchers investigate the impact f the 2009 influenza A/H1N1 pandemic n the attitudes twards general vaccinatin amng residents living in France. The authrs cnclude that unfavrable attitudes twards vaccinatin in general have dramatically increased frm 8.5 % in 2000 and 9.6 % in 2005 t 38.2 % in During 2010, unfavrable attitudes varied significantly during different perids f time. All age grups expressed an increased negative apprach during the study perid, while higher educatin- and incme levels were factrs assciated with less ppsed attitudes twards vaccinatins. As pinted ut, lw sciecnmic grups have mre sensitive risk perceptins and are thus mre prne t distrust authrities which are a key issue t btain high vaccinatin cverage amng its citizens. Rachitis et al. (2010) explred, during the pandemic, the attitudes amng Greek healthcare wrkers twards the A/H1N1 vaccinatin. The data reveal that vaccine uptake during this time perid was lw. The mtivatin fr the lw uptake was due t lw perceptin f defining the illness as serius but als the fear f side-effects. It was fund that the acceptance f the vaccine increased with aged and with infrmatin received frm primarily medical jurnals. The cncerns regarding pssible side-effects n the ther hand were als dependent n surce f infrmatin, specifically targeting the mainstream media channels. Börjessn and Enander (2013) examine perceptins and scidemgraphic factrs influencing vaccinatin uptake and precautinary behavirs in respnse t the A/H1N1 influenza in Sweden. The study was cnducted during the final phase f the implementatin f the Swedish vaccinatin prgram in 2010, which was befre the intense debate regarding the relevance f the vaccinatin. The variables which defined risk t get infected were in this study subjective and was based n the respndents wn perceptin. The strngest reasn fr nt becming vaccinated were cncerns

9 9 related t the lw threat perceptin f the A/H1N1 and pssible side-effects assciated with the vaccine. Lw vaccinatin rates were as well assciated with demgraphic- and sci-demgraphic factrs such as lw age, educatin and incme. A similar study with cmparable cnclusins was executed by Seal et al. (2010), addressing the Australian public perceptins twards the A/H1N pandemic and the willingness t accept the influenza vaccine. N distinctin was hwever made between the subjective and the bjective risk perceptins. Main reasns fr nt vaccinate cncerned the respndents perspectives as regarding the swine flu as nt serius, nt being at risk and fear f side-effects. The data frm 2009 suggests that vaccinatin cverage in adult age grups (18-64) remained lw, but was three times higher (42 %) in the lder grup. Björkman & Sanner (2012) explres in a qualitative study the Swedish A/H1N1 vaccinatin campaign and the mtives, beliefs and reactins f individuals with varying backgrunds, wh did nt get vaccinated. The cnclusins crrespnd with previusly findings where respndents unwillingness t be immunized was related t the subjects wn risk perceptin. Trust twards public authrities is related t the uptake f vaccinatin, the respndents regarded the public infrmatin nly as an additinal surce amng thers. The respndents further stressed the lack f mtivatin t be immunized and felt that recmmendatins alne frm respnsible authrities were nt enugh t influence the vaccinatin uptake amng them. In a study cnducted in Germany during the A/H1N1 pandemic 2009/2010, Walter et al. (2012) researched the changing attitudes f the public. During the peak f the pandemic nly 18 % f the participants claimed that the risk f cntracting influenza was high. The vaccinatin cverage was lw in Germany, even in the targeted risk grups. The main reasns were mentined as fear f adverse effects and perceptins that the vaccine was nt fully evaluated. By using a health belief mdel, the authr claimed that the tw majr factrs influencing vaccine decisins cncerns risk perceptin and a view that the preventive measurements are safe and

10 10 effective. Risk perceptins pstulated by the media were explained t exaggerate the situatin in Germany. Similar findings are utlined by Steelfisher et al. (2010). The tw majr reasns t nt vaccinate in the United States cncerns vaccine safety, side-effects and fear f getting ther additinal diseases. The secnd reasn was that the vaccine was nt regarded as needed and respndents valued their persnal health as adequate and ut f risk t get serius cmplicatins f the disease. In 2009 rughly 40 % f the respndents thught that the vaccine was prduced t fast t guarantee its safety. Perssn et al. (2013) researched in a mst recent cmprehensive study the risks f neurlgical and immune-related diseases, including narclepsy, after vaccinatin (against A/H1N1) with Pandemrix. The findings supprt the increased risk in children and adlescents t suffer frm narclepsy after vaccinatin with Pandemirx. The chrt study bserved a three-fld increased risk f a diagnsis f narclepsy amng peple aged (2.92, 95% CI: ). Due t this backgrund there are signs f a grwing anti-vaccinatin mvement where reduced reliance twards authrities and medical expertise is distinguished (Peretti-Watel et al. 2013). While sme factrs appear quite universally significantly, distinct natinal variatins exist. Several studies have aimed at understanding the perceptins and the changing attitudes twards the A/H1N1 vaccinatin amng the public. Often such studies distinguish the subjects wn risk perceptin f the influenza and side-effects as determinatin t receive vaccinatin (Walter et al. 2012; Björkman & Sanner, 2012; Seale et al. 2010; Rachitis et al. 2010; Steelfisher et al. 2010). As attitudes and behavirs are generally cnsistent ne with anther, this phenmenn culd have cnsiderable impact n future vaccinatin cverage. Hwever, little is knwn abut hw chrnically ill patients and ther grups identified at risk perceive the A/H1N1 vaccine cmpared with peple nt at risk (Peretti-Watel et al. 2013), making the aim f this present study valuable fr further in-depth understandings.

11 11 4. Material and Methd Since the study purpse was t examine different attitudes twards the A/H1N1 vaccine amng different grups and cmpare these findings, a quantitative apprach was cnducted using questinnaires. The infrmatin cllected was carried ut with a standardized apprach, with the main gal that the infrmatin cllected shuld be as generalizable as pssible. Data was cllected by systematic structured clsed categrical questin. A Likert scale was used as a measuring tl in rder t quantitative transfrms the measurement f attitudes. The questins were prepared in advance where even answer chices were fixed. 4.1 Questinnaire The chice f methd is mtivated based n the eligibility t address the research bjective and research questin. In rder t address attitudes and perceptins amng citizens in Stckhlm this chice f methd is preferable. Other criteria regarding selectin f questinnaires are the cheap administer advantages and the ability t cllect large samples in a less time cnsuming way (Hlme & Slvang, 1997). Williams (2003) argues that the placement f wrds, language used and placement f questins and statements in the questinnaire has a direct impact n the respnse rate. With this in mind, the questins were created with the ambitin t be shrt, using simple language and strategically placed statements in a lgical rder. General demgraphic questins were thus included early in the placement rder. In additin, a facility in Micrsft Wrd was used and enabled t calculate the reading ability f the questins using the Flesch Reading Ease Scre test (FRES) (Micrsft Office, 2014). As previusly mentined, the questins were designed using a selfcmplete structure with clsed dichtmus questins. Hwever, tw exceptins were made where the respndents had the ptin t answer using multiple tick bxes. The demgraphic questins (questins 1-7) in such were used primarily as inclusin criteria t define risk grups and nn-risk grups. Additinal fllwing statements in the questinnaire explred the respndents attitudes twards vaccinatin. In such case the respndents

12 12 were asked t what extent they disagree r agree abut certain issues, using a Likert scale with a fur-pint scale. The first grade n the pint scale indicate that the respndent cmpletely disagree and clser t number fur n the pint scale the mre the respndent agree in the presented statement. It is cmmn t use a five-pint scale when cnducting a Likert scale. Hwever, in rder t influence the respndents t avid neutral answers the fur pint scale was mtivated and cnsequently the respndents was merely urged t select a side f pinin. The questinnaires given t the respndents were presented in Swedish. 1 An English versin is fund in (Appendix 1). 4.2 Selectin and limitatins In rder t identify participants, respndents were lcated utside health centers, face-t-face. The research area was limited t nly include districts in the inner-city f Stckhlm due t reduce the influence f nnrepresentative respndents where sciecnmic factrs, language skills and ther culd affect the utcme. Since it is nt pssible t investigate an entire ppulatin due t ecnmic- and time cnstraints sampled units and respndents are utilized. The theretical ppulatin is residents in Stckhlm. A restrictin has been made t nly include the central districts. In rder t btain an bjective and representative sample the districts and health centers were sampled based n a randmized prbability sample using additinal functins in Micrsft Excel. Hwever, since it was nt pssible t cmpile a selectin frame fr the entire ppulatin t sample frm, the respndents were sampled based n a nn-randm prbability sample. Hence, the respndents included in this study are the nes available at the time (Hlme & Slvang, 1997). Every ptential respndent present during that specific time had equal pprtunity t participate in the study. This chice f selectin f sample is smehw justified based n the time- and ecnmic cnstrains this study 1 The Swedish versin f the questinnaire can be fund n: - d_a/viewfrm

13 13 experienced. The addressed restrains regarding chice f sample has been acknwledged since cincidentally selectins is nt representative f the ppulatin as a whle and can lead t misleading cnclusins abut the ppulatin. This is smething that has been regarded during the analysis and interpretatin f the data. 4.3 Data Cllectin Respndents were apprached face-t-face utside the selected health centers. All respndents present during the data cllectin had equal pssibilities t be included in the study. All data was cllected during the perid April 14 t April 26, Pre-pilt and Pilt study T be able t create and cllect valid and reliable data the questinnaire initially underwent an infrmal pre-pilt prcedure and a mre frmal pilt study. In bth cases the external input frm students and ther subjects were lcated at Södertörn University Cllege. These respndents were met based n a face-t-face apprach. A mre detail explanatin n hw this was carried ut is explained in the fllwing sectin regarding Validity, Acceptability and Reliability. 4.5 Validity and acceptability Williams, (2003) define validity, in the cntext f questinnaires, as the ability t measure what it aims t measure. Thus, the measurements shuld be relevant t the bjective and the questins shuld directly target the main research questin. Validity, in mre practical terms includes the criterin validity and face validity. Criterin validity was met with a mixed result. In sme cases questins were reused frm already established questinnaires used by healthcare wrkers in Sweden. Such questins addressed mainly demgraphic tpics, but als the respndents wn health status. Thse questins that were self-created were evaluated in the pilt study. Face validity was as well btained in the pilt study by interviewing the respndents after cmpleting the questinnaire and asked whether the respnses crrespnd t their real pinin. In same discussin the students

14 14 were urged t give pinins f the questinnaire. This input led t changes in the placement rder f tw f the questins and the inclusin f additinal ptins f risk factrs. 4.6 Reliability Reliability, in the cntext f using questinnaires as an instrument t cllect data, is referred t as if several independent measurements f the ne and same phenmena prvide similar result. The prcess t btain high reliability in this case refers t the test-retest reliability. Mst ften this is tested by prviding the questinnaire t ne grup in tw different pints in time. Since there is a shrt defined time limit during this study, this prcedure was nt pssible. Hwever, internal cnsistency and reliability was tested during the pilt study by including ne questin in the questinnaire that was asked nce again but rephrased (Williams, 2003). It is further stressed that the interpretatin f the questins is a central prblem during a survey research. T include as clear statements as pssible, the inclusin criteria f the statements were based n a judging prcess carried ut by students at Södertörn University Cllege. This prcess was cnducted befre the pilt test. The students rated hw favrable each statement was with respect t the cnstruct f interest. The intercrrelatin (item-ttal crrelatin) between the judging scres and all pair f items were cmputed. Based n these ratings, any item identified with a lw crrelatin was remved. Using such prcess five statements with lw crrelatin were eventually excluded frm the questinnaire. During this prcess a crrelatin value f 0.45 was used as a cutff pint t determine the inclusin and exclusin criteria f the statements. In rder t further meet the validity and reliability criteria the questinnaire, layut and statements was pre-pilt tested. The intentin f the pre-pilt study was t make sure that the statements was apprpriate and acceptable, which was dne with discussin alng with supervisr and ther subjects.

15 Respnse rate Using questinnaires and the face-t-face distributin a respnse rate was fllwed by 68 %. Out f the 150 respndents participating in this study an additinal 70 respndents declined t participate. T evaluate if the data might be biased, the nn-respnse rate was met with an internal recrd f categrizatin f demgraphic factrs t allw a brief descriptin f the targeted grup. This grup was slightly verrepresented by peple lking yunger. The gender distributin was similar. The majrity f peple declining t participate did s withut any knwledge f study tpic. In such, there is n reasn t imply that this grup represented a hmgenus grup, sharing a cmmn belief r pinin regarding the study bjective. Out f the 150 participants included in this study nine respndents did nt cmplete ne f the asked questins r statements. In such, incmplete demgraphic respnses culd be cmpleted based n already sufficient infrmatin. In case where statements were incmplete the missing value was replaced with a mean average frm the scre value frm the ther asked statements. 4.8 Methdlgical limitatins Firstly, the chice f selectin f sample is smehw justified based n the time- and ecnmic cnstrains this study experienced. It is therefre acknwledged that the cllected cincidentally samples might nt be representative f the ppulatin as a whle and that the utcme f this study is limited. This is smething that has been regarded during the analysis and interpretatin f the data in this research. Hwever, based n previus findings the data are cmparable. The vaccine cverage f 62 % in Sweden crrespnds well t the findings f this study (54 %). The vaccinatin cverage between gender fllw similar distributin, the cverage amng men (57.2 %) and wmen (67.2 %) crrespnds well with the current findings (52 % men and 56 % amng wmen). In bth cases the frequency f vaccinatin are slightly verrepresented by wmen. It is further stressed in bth studies that respndents aged 65, indicate the highest vaccinatin uptake f 69.3 % cmpared t 64 % (Börjessn &

16 16 Enander, 2013). Secndly, the inability t cmpletely cntrl fr the reliability assciated with the creatin f the questinnaire culd have an impact n the utcme. In such, the test-retest prcess was neglected due t reasns already mentined, meaning that the questins are under the influence f different subjective interpretatins. Thirdly, the attitudes expressed by the respndents in this study were cllected during ne specific time perid. The perceptins and attitudes given by the participants are in such case dynamic and might change during time and with new infrmatin. 4.9 Data analysis Once the questinnaires were cllected the data fr each respndent was summited based n the existing cde scheme. In case where the items were reversed in meaning frm the verall directin f the scale, the respnse values were reversed. Once the data had been cllected and cmpiled in Excel, the data was prcessed and transfrmed int statistically units t enable the interpretatin and evaluatin using statistical sftware R versin Since the dependent variables were treated as cntinuus and the independent variables as categrical, general linear mdels where used. The data fllwed nrmal distributin and thus parametric tests were enabled. In case when the differences between tw independent samples were explred, welch tw sample t-test was used. In three cases single asked statements were analyzed. In such case, the data fllwed a slightly skewed but still nrmal distributin, the t-test was thus mtivated due t the rbustness and high pwer f such data characteristics. Where tw r mre categrical variables were examined an ANOVA type II test was required fr statistical prcessing (Grandin, 2003).

17 17 5. Result The fllwing results present the crrelatins between attitudes twards the A/H1N1 vaccine amng different grups. The explanatry variables researched are primarily the assciatin between belnging t a risk grup r nt, using bjective definitins prvided by Swedish authrities. This variable is als intercrrelated with ther demgraphic factrs such as gender, age and vaccinatin status. A ttal f 150 peple participated in this study. They were apprached in three different health centers lcated in different inner city districts. The data in (Fig. 1) reveal that wmen are slightly verrepresented cmpared t men with a distributin f 56 % respective t 44 %. Other demgraphic data such as age tend t represent mre elderly; nearly 70 % f the respndents were aged 46 r lder. Apprximately 41 % f the respndents belnged t a risk grup while the ther 59 % did nt. A ttal f 54 % f the respndents were immunized with the A/H1N1 vaccine. An verview f further descriptin f the participating respndents can be fund in (Table 1). Fig 1. An verview f central demgraphic factrs such as gender and age amng the respndents.

18 18 Table 1. Demgraphic characteristics f the participants included in research. Vaccinated (%) Nt vaccinated (%) Risk (%) Nt in risk (%) Gender Men 34 (52) 32 (48) 27 (41) 39 (59) Wmen 47 (56) 37 (44) 35 (42) 49 (58) Age (30) 7 (70) 2 (20) 8 (80) (53) 18 (47) 6 (16) 32 (84) (52) 29 (48) 12 (20) 48 (80) (64) 15 (36) 42 (100) - Ttal 81 (54) 69 (46) 62 (41) 88 (59) When cmparing the difference between the risk grup and the nn-risk grup and the effect n the respnse twards the vaccine, significant differences can be distinguished. The risk grup had mre favrable attitudes (± SD= 33.31± 6.1) twards the A/H1N1 vaccine cmpared t the nn-risk grup (± SD= 27.32± 5.92) (p<.001, welch tw sample t-test, t( )= , CI ). In (Fig.2) the crrelatin between these variables and the respnse f attitudes is further visualized. The dashed lines illustrate the spread and the black markers indicate the central tendency. The higher the means, which are presented n the Y axis, the mre favrable are the attitudes twards the A/H1N1 vaccine. This result supprts that p<0.05, there is sufficient evidence t reject the null hypthesis (H 0 ) and accept the alternative hypthesis (H 1 ).

19 19 Fig. 2 Graphic visualizatin f the grups and attitudes twards vaccinatin. The dashed lines represent the spread f values and the slid black markers indicate the central tendency presented by the belnging t different grups. On the X axis the different grups are displayed and n the Y axis the attitudes twards the vaccine is represented. Thse in a risk grup expressed mre favrable attitudes twards the vaccine. The utcme between the crrelatin f the explanatry variables gender and risk grup and nn-risk grup as the functin f the respnse f attitudes, present the fllwing result. Fr the 27 men in a risk grup the mean was (SD= 7.37). The mean fr the 39 men in the nn-risk grup was lwer, (SD= 6.72). The crrespnding mean values fr the 35 wmen in risk was (SD= 4.99) and fr the 49 wmen nt in risk the mean was (SD= 5.25). Fllwing the result in the ANOVA type II test table (Table 2), merely the risk grup had a significant effect (p<0.05) t explain the different attitudes. Thse participants belnging t a risk grup was shwn t have an increased mean value twards the respnse cmpared

20 20 t the nn-risk grup, implying that thse in risks was mre in favr t the A/H1N1 vaccine. The cntrl f impact f ther variables as gender, the cmbinatin f gender and risk grup/nn-risk grup as a pssible explanatry variable, fund n significant difference effect (p>0.05). There is insufficient evidence t reject the null hypthesis (H 0 ). Table 2. Gender and risk grup effect n the respnse twards vaccinatin. 2 Sum Sq Df F Value P Gender Risk Grup Gender*Risk Residuals The descriptive result frm the crrelatin between the variables age and risk grup/n risk grup is reprted as fllwed. The age distributin fr peple in the yungest age grup was represented by tw peple in risk with a mean f 32.5 (SD= 2.12) and respectively eight peple was nt in risk with a mean f 24.5 (SD= 3.7). Cmparable descriptin f respndents in age grup is acknwledge as six peple in risk with a mean f 28.5 (SD= 7.48) and thse 32 peple nt in risk had a mean f (SD= 6.88). Peple aged and in a risk were represented by 12 peple, with a mean f (SD= 6.6) while the 48 peple in the same age grup but nt in risk had a mean f (SD= 5.3). Finally, peple aged 65 and in risk cnstituted f 42 peple with a mean f (SD= 5.32). The fllwing results in the (ANOVA type II test) table (Table 3) supprt the findings with a significant p value belw the 0.05 threshld. Hence, age has an effect n the respnse twards the vaccine. Peple aged 46 r mre can be described t have mre favrable attitudes twards it. Hwever, the 2 ANOVA table (Type II test)

21 21 cmbinatin f including the variables risk and age shw n relevant finding (p>0.05). Table 3. ANOVA table (Type II test) presenting the effect f the different variables age and risk grup. Sum Sq Df F Value P Age Risk Grup Age*Risk Residuals The demgraphic data presented by the intercrrelatin between vaccinatin and the different grups and the effect n attitudes twards the A/H1N1 vaccine, is presented in (Table 4). It is fund that peple assciated with being vaccinated als reprt the highest mean values. Table 4. Descriptive table presenting vaccinatin and risk grups. Vaccinated Nt Vaccinated ± Mean SD Risk Grup Yes N As presented in the ANOVA table (type II test) fund belw in (Table 5) all variables explred shwed statistically significant interactins (p<0.05). These findings supprt the alternative hypthesis (H 1 ), meaning that there are differences amng the grups, all variables tested supprt a significant effect n the respnse. The main effect f the interactin indicate that the bserved variables interact. In ther wrds, the different attitudes twards the vaccine are dependent n if ne are in a risk grup r nt, but the effect is different fr vaccinated and nt vaccinated. Respndents which were vaccinated, independent f risk status, expressed mre favrable attitudes

22 22 when cmpared t ther grups. The finding als cncludes that respndents nt vaccinated but in a risk grup expressed mre psitive attitudes twards the vaccine, while cmpared t peple nt vaccinated and nt in a risk grup. Table 5. Effect interactin between the different variables vaccinated and risk grup. 3 Sum Sq Df F Value P Risk Grup Vaccinated Risk*Vaccinated Residuals The illustratin f the interactin between the variables can be fund in the effect plt (Fig.3) n page 23. The left side f the graph includes thse nt vaccinated and thse vaccinated are presented n the right side f the graph, n the X axis the risk grup and nn-risk grup are visible. In similar structure the attitudes twards the A/H1N1 vaccine is represented as means n the Y axis. The higher mean value n the Y axis the mre psitive assciatins twards the vaccine are expressed. This graph prvides a clearer verview f the interactin. Peple vaccinated r in a risk grup tend t have a mre favrable apprach regarding the vaccine. Peple nt vaccinated and nt in risk pse a mre restrictive apprach regarding immunizatin against A/H1N1. 3 ANOVA table (Type II test)

23 23 Fig. 3 The effect plt indicates the interactin effect between the variables vaccinatin and risk grup and the utcme f attitudes (sum) fund n the Y axis. Thse nt in risk and nt vaccinated expressed the mst negative cncerns regarding the vaccine. While further examine the result, the respnses twards tw central statements included in the questinnaire are highlighted and reprted as fllwed. When asked t which degree the respndent think that the vaccine is safe, the peple belnging t a risk grup were mre likely t agree (± SD= 2.73± 0.94) while the nn-risk grup was mre likely t nt agree (± SD= 2.03± 0.88) (p<.001, welch tw sample t-test, t( )= , CI ). In (Fig.4) the result f asked questin is further visualized.

24 24 Fig. 4 Graphic visualizatin f perceptins f side-effects. The dashed lines represent the spread f values and the slid black markers indicate the central tendency presented by belnging t the different grups. Thse nt in risk expressed mre cncerns regarding side-effects. Finally, when asked abut a single statement (statement number 17 in appendix 1) cncerning the respndents willingness t immunize and the relatin t their wn health, the risk grup was mre likely t vaccinate referring t inadequate health status (± SD= 2.95± 1.06). The nn-risk grup was mre likely t nt vaccinate claiming sufficient health (± SD= 2.23± 1) (p<.001, welch tw sample t-test, t( )= , CI= ). The crrelatin is graphically presented in (Fig 5) fr easier interpretatin. Similar result is true when further explring the same statement amng thse vaccinated (± SD= 2.86± 1.05) and the nn-vaccinated grup (± SD= 2.1± 0.95) (p<.001, welch tw sample t-test, t( )= , CI= ).

25 25 Fig. 5 Graphic visualizatin f the means. The dashed lines represent the spread f values and the slid black markers indicate the central tendency presented by belnging t the different grups. On the X axis the different grups are displayed and n the Y axis the mean is represented. Thse in a risk grup was mre likely t vaccinate claiming insufficient health.

26 26 6. Analysis The main purpse f this study was t examine the different attitudes twards the A/H1N1 vaccine amng peple defined as a risk grup and peple defined as a nn-risk grup in Stckhlm, Sweden. Findings that can prvide imprtant input fr future health interventins. Based n these findings there are significant differences between the attitudes twards the vaccine and the identificatin t a specific grup. Respndents categrized as a risk grup expressed mre favrable attitudes twards the A/H1N1 vaccine cmpared t thse wh were nt at risk (H 0 rejected). While further explring the explanatry factrs, this study indicate that gender shwed n significant effect while examining the utcme f attitudes twards the vaccine. It is merely shwn that favrable attitudes (independent f gender) twards the vaccine were expressed by peple in a risk grup. It is als fund that age, independent f risk as a factr, reveal a significant effect, where middle-aged peple and lder peple expressed mre favrable attitudes twards the vaccine cmpared t yunger age grups. In additin, the analysis f the intercrrelatin between vaccinatin and risk and the effect n attitudes twards the vaccine indicate that vaccinated peple express the mst favrable attitudes. Hwever, since all factrs shwed significant crrelatins, all variables are fund t interact. Favrable attitudes are explained by being included as a risk grup but the effect is different fr thse vaccinated and nt vaccinated. These finding cnclude that thse respndents which were vaccinated, independent f risk status, were mre in favr twards the vaccine. It implies that the utcme f pr vaccinatin attitudes largely depend n factrs relating t the subjects wn safety cncerns and previus vaccinatin experiences. Furthermre, it is stressed that peple in a risk grup wh were nt vaccinated als had a greater psitive perceptin regarding the vaccine, cmpared t thse whm were nt in risk and nt vaccinated. This implies that a prprtin f the mst vulnerable grup decided nt t vaccinate even thugh expressing favrable attitudes twards it, a view which supprt that

27 27 additinal factrs are likely t influence the respndents decisin t immunize. It is questinable whether this grup expressed mre cncerns regarding sme specific safety aspects f this vaccine but simultaneusly expressed an verall psitive pinin. It is als likely that different infrmatin surces regarding vaccinatin affected this grup differently cmpared t the risk grup which was vaccinated. The utcme f this study is further explred in tw highlighted questins. When the respndents were asked whether r nt they agree t believe that the vaccine against swine flu may cause serius side-effects, the risk grup had less trubled cncerns regarding vaccine safety and the ptential side-effects f the vaccine. The nn-risk grup expressed mre anxius pinins regarding the safety issues related t the vaccine. When asked if the respndents d nt vaccinate because f already gd health, the risk grup was mre likely nt t agree and accept the immunizatin. The ppsite assumptins were expressed amng the nn-risk grup, they were mre likely t decline vaccinatin referring t an already gd health. When asking the same questin regarding subjective health amng thse vaccinated and nt vaccinated, similar respnses were given. Respndents wh were vaccinated were mre likely nt t agree while the ppsite assumptins were true fr thse nt vaccinated. This infrmatin further supprts the perceptins that thse peple in a risk grup (based n bjective definitins) als perceive their wn health as mre vulnerable and mre susceptible fr severe cmplicatin due t infectins, the same explanatins are valid fr thse vaccinated. Yet, the ppsite assumptins are als true, peple nt in risk r vaccinated d nt address the same safety cncerns and are mre cmmn t refer t an already existing gd health status. T summarize, the variatins f attitudes twards the vaccine are fund t be dependent n risk perceptins and vaccinatin status. The risk perceptins amng thse in a risk grup were higher when cmpared t thers. The assciatins t a risk grup and vaccinated are fund t relate t mre favrable perceptins twards the immunizatin.

28 28 7. Discussin In this presented study, sciecnmic factrs were aimed t be cntrlled fr during the selectins f the participants, with the intentin t cmpare as equal grups as pssible and islate the effect in rder t avid previusly fund cnfunders. Generally, previus studies have shwn that sciecnmic factrs such as lw educatin- and incme level are persistent in influencing the negative apprach twards health authrities and the uptake f immunizatin. It is als mentined that the refusal by well-educated parents t vaccinate their children are mtivated by subjective risk- and benefits assessments (Peretti-Watel et al. 2013). This study has shwn, being at risk (bjective definitins) and vaccinated are bth factrs assciated with favrable attitudes twards the vaccine while the ppsite assumptins are valid fr the mre skeptical grup. Such findings are cmparable t subjective definitins explred in previus research (Walter et al. 2012; Steelfisher et al. 2010; Rachitis et al. 2010; Seal et al. 2010; Börjessn & Enander, 2013). The tw mst cmmn factrs influencing vaccine decisins are related t the subjects wn perceptin f risk and vaccine safety. Fear f side-effects and lw perceptin f risk were cmmnly assciated with the reasns fr nt becming immunized. This view is supprted based n the current findings that peple described with additinal health cnditins and in a risk grup, at a larger extent accepted the A/H1N1 vaccine due t a higher risk perceptin. The ppsite argument is valid in the nn- risk grup and nt vaccinated grup, since they mre generally decline health recmmendatins referring t adequate health; a view that supprt a lwer risk perceptin. The perceptin regarding the influenza as severe is strngly assciated with an intentin t take the vaccine. It has previusly been explred that sme peple experienced this decisin as balance between the risk assciated with the disease and the risk assciated with the vaccine (Steelfisher et al. 2010). Hwever, the cntributin f this present study t previus research is the understanding, that bjective risk definitins als

29 29 are valid regarding the subjects wn definitins. In ther wrds, peple defined as in a risk grup als perceived themselves as mre vulnerable, in which vaccine as an external safety measurement are mre accepted. Such identificatins are imprtant regarding epidemilgical cncerns in cntrlling and sustaining gd health during endemic r pandemic utbreaks. This reasning is significant in the sense that the mst vulnerable peple als are the nes mre susceptible twards vaccine uptake as a health measurement. It is simultaneusly f cncern, that peple nt identified themself t the risk reject the needed prtectin. The cncept f immunity induced by vaccinatin in susceptible peple is essential in infectius disease epidemilgy. In case f infectius diseases, the purpse f herd immunity, which is dependent n high vaccinatin uptake, becmes even mre imprtant in cntrlling the spread f the disease (Giesecke, 2002). Such arguments t vaccinate are nt entirely bvius, as mentined by Björkman & Sanner (2010), nne f the respndents wh declined vaccinatin, expressed any cncern t prtect thers. In retrspect, the utcme f the pandemic influenza A/H1N1 in Sweden was nt as severe as expected. The respndents wh did nt perceive the disease as a serius threat was t a larger extent nt vaccinated. Hwever, risk perceptins in a ppulatin are nt static but dynamic (Björkman & Sanner, 2012). As further pinpinted by Steelfisher et al. (2010), such behavir r expressins change, even during a pandemic. Peple declining vaccinatin due t lw risk perceptins als cncluded that if mre serius utcmes were nticed their pinins and actins wuld als very likely change, since the main cncerns regarding neglecting the vaccine primarily is fcused n the prtectin f their wn health. The skeptical pinins given by the respndents during this study twards recmmended safety measurements are in such case nt influenced by strng philsphical assumptins. The findings which aim t explain the differences f attitudes between the researched grups, are thus nly valid in the cntext f the specific cnditins f A/H1N1, and shuld therefre nt be applied t ther (future) circumstances withut precautins.

30 30 Previus studies have fund that infrmatin surces have a great impact n the public s risk perceptins and vaccinatin behaviur. The different media channels have the ability t bth cntribute t the creatin f sceptical reactins but als t generate psitive respnses twards public recmmendatins. It is fund that peple aged 60 r lder are mre frequent users f cnventinal infrmatin surces then ther age grups, lder peple and vaccinated are mre likely t depend their decisin n the expertise f physicians instead f alternative media surces (Walter et al. 2012). Such remarks suggest additinal interpretatins regarding why peple nt in risk but vaccinated expressed mre favurable attitudes twards the vaccine. The same arguments are valid fr the risk grup which was nt vaccinated. In such case there is likely that medical expertise as an infrmatin surce is f fundamental imprtance regarding vaccine decisin and health benefits. It is imprtant that infrmatin reaching mainstream media is based n reliable quality and is reprted in a nn-exaggerated way. The data suggests that in case f future pandemics, recmmendatins regarding immunizatin shuld be crrelated with high risk perceptins amng the general public. If nt, the uptake might be neglected by peple experiencing a lwer subjective risk. Furthermre, it is argued that sme f the respndents wh belnged t a risk grup were nt immunized, even thugh they expressed psitive attitudes twards it. In such case it is evident that additinal factrs exists that influence their decisins and future studies shuld aim t address such behaviurs. Since immunizatin cnstitute the ne single mst imprtant health preventin measurement pssessed by public health authrities during utbreaks f infectius diseases, future health implementatins shuld recgnize recent findings in rder t avid plarized behaviurs amng its citizens.

31 31 8. Cnclusin Immunizatin is recgnize as ne f the single mst imprtant health measurements during pandemics, with the ability t cntrl the spread f disease and lwering the pssible substantial health csts. This study has explred the different attitudes twards the A/H1N1 vaccine in Stckhlm, Sweden. In spite f the ptential methdlgical weaknesses, this study des distinguish different public attitudes twards vaccinatin. The findings cnclude that risk perceptins are central in determine vaccinatin uptake amng the ppulatin. Peple defined as a risk grup r vaccinated express mre psitive attitudes twards immunizatin. It is als distinguished that vulnerable peple and vaccinated had a lwer negative cncern regarding vaccine safety and a mre psitive apprach twards vaccinatin and the need t vaccinate. Peple nt in risk and nt vaccinated cnstituted fr a mre sceptical apprach regarding safety and was mre likely t neglect the vaccine referring t already gd health status. It is evident that peple in risk (bject definitins) als define themselves as mre vulnerable (subjective definitins). Hwever, it shuld be stressed that sme respndents wh belnged t a risk grup was nt vaccinated, even thugh they expressed psitive attitudes twards it. In such case it is evident that additinal factrs exist that influence their decisins. This study cncludes that in case f future pandemics, vaccine uptake is strngly crrelated with peples subjective and bjective risk perceptins. It is imprtant fr future health interventins t acknwledge these behaviurs.

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