Fliou, Fay ouz
A icle
Na iga ing he nexus o COVID-19 accina ion s a egies:
Insigh s beyond he needle
The Eu opean Jou nal o Compa a i e Economics (EJCE)
P o ided in Coope a ion wi h:
Uni e si y Ca lo Ca aneo (LIUC), Cas ellanza
Sugges ed Ci a ion: Fliou, Fay ouz (2024) : Na iga ing he nexus o COVID-19 accina ion s a egies:
Insigh s beyond he needle, The Eu opean Jou nal o Compa a i e Economics (EJCE), ISSN
1824-2979, Uni e si y Ca lo Ca aneo (LIUC), Cas ellanza, Vol. 21, Iss. 2, pp. 265-284,
h ps://doi.o g/10.25428/1824-2979/033
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The Eu opean Jou nal o Compa a i e Economics
Vol. 21, no. 2, pp. 265-284
ISSN 1824-2979
h p://dx.doi.o g/10.25428/1824-2979/033
Fi s published online: 07/02/2025
Na iga ing he nexus o COVID-19 accina ion
s a egies: insigh s beyond he needle
Fay ouz Fliou*
Abs ac :
The COVID-19 pandemic has w ough global dis up ions, impac ing socie ies and economies signi ican ly,
while accine hesi ancy emains a p essing conce n. This pape in oduces a amewo k o analyzing
accina ion decision-making, emphasizing he oles o pe cei ed cos s and social in luences. To c a
e ec i e policies, comp ehending indi iduals' cos pe cep ions is essen ial. Social imi a ion also plays a ole
in accina ion choices, as indi iduals o en emula e hei social ci cles, po en ially al e ing he op imal
decision. The es ablished amewo k demons a es ha COVID-19 policies success ully encou aged
accina ion h ough cos - ela ed s a egies. Howe e , simila challenges may eme ge in u u e c ises.
The e o e, es ablishing con inual in o ma ion dissemina ion and educa ional p og ams a ge ing accine
hesi ancy is c i ical. By consis en ly add essing his hesi ancy, au ho i ies can na iga e po en ial obs acles
and bols e hei esponses o u u e heal h eme gencies.
Keywo ds: COVID-19 pandemic; Vaccine esis ance; Vaccina ion decision-making; Social
in luences; Heal h policies
1. In oduc ion
The global impac o he COVID-19 pandemic has been no hing sho o
de as a ing, compa able o he magni ude o a Sep embe 11 a ack un olding e e y 1.5
days (Ande son e al., 2004). This unp eceden ed c isis has placed an o e whelming
bu den on heal hca e sys ems wo ldwide, leading o a signi ican su ge in cases and
a ali ies (Epidemiology Wo king G oup o NCIP Epidemic Response, 2020). Beyond
i s immedia e heal h impac s, COVID-19 has exposed ulne abili ies in public heal h
sys ems and magni ied exis ing economic challenges. Mo gan i (2023) highligh ed he
c i ical need o coo dina ed policy in e en ions, especially in imes o heigh ened
unce ain y and public heal h c ises.
In he igh agains he ansmission o in ec ious diseases, accina ion has eme ged
as a c i ical and indispensable s a egy o in e en ion and con ol. I is widely ecognized
as one o he mos e ec i e measu es o mi iga e he mo bidi y and mo ali y associa ed
wi h such diseases (Linds and e al., 2021; Tille , 1992). Howe e , he issue o
accina ion has long been a subjec o social dilemma o public heal h au ho i ies.
* Uni e si y o Tu in, depa men o economics and s a is ics "Cogne i de Ma iis".
The au ho s would like o hank he edi o and he anonymous e iewe s o hei commen s and
sugges ions, which signi ican ly imp o ed he quali y o his pape .
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Despi e he o e whelming scien i ic consensus on he sa e y and e icacy o
accines, pe sis en claims ques ioning hei sa e y con inue o ci cula e (La son e al.,
2021).
Fu he mo e, he ou b eak o he COVID-19 pandemic has u he in ensi ied he
ongoing deba e su ounding accina ion egula ions and has spa ked conce ns ega ding
indi idual igh s. In addi ion, poli ical agmen a ion and heal h sys em capaci y ha e been
shown o signi ican ly in luence coun ies' esponses o he COVID-19 pandemic (B osio
e al., 2022), shaping he speed and e icacy o policy implemen a ion. These ac o s also
in e sec wi h public pe cep ion, as hey a ec us in go e nmen and he heal hca e
sys em, bo h o which a e c i ical de e minan s o accine up ake and b oade public
heal h compliance.
Th oughou he cou se o se e al cen u ies, he ield o epidemiological modeling
has wi nessed ema kable ad ancemen s, bo h in e ms o concep ual unde s anding and
echnical capabili ies. These de elopmen s ha e enabled esea che s o analyze he impac
o a ious con ol s a egies on he ansmission o diseases (Bacaë , 2011; Xia and Lui,
2013; Buonomo and Laci ignola, 2011; Cai e al., 2014; Eckalba and Eckalba , 2011).
Ma hema ical modeling, in pa icula , has played a pi o al ole in he ealm o
epidemiology, p o iding aluable insigh s in o in ec ious diseases and acili a ing he
assessmen o con ol measu es. One c ucial aspec o disease con ol e ol es a ound
achie ing and sus aining adequa e accina ion co e age (Fe guson e al., 2006; La son e
al., 2011; Black and Rappuoli, 2010). The e o e, he e ec i eness o a accina ion
p og am hinges upon he p opo ion o he popula ion ha ecei es he accine, as
indi idual choices o ei he ge accina ed o no signi ican ly in luence he collec i e
ou comes o accina ion endea o s (Gal ani e al., 2007; Wu e al., 2011). By su passing
he c i ical h eshold o he d immuni y, whe ein a subs an ial segmen o he popula ion
becomes immune, accina ion eme ges as a po en ool in hwa ing he widesp ead
ansmission o he in ec ion (Fine e al., 2011; John and Samuel, 2000).
In explo ing he decision-making p ocess su ounding accina ion, esea che s
ha e employed game- heo e ical analyses, which ake in o accoun a ious ac o s such as
pe cei ed cos s and bene i s, in ec ion isks, accine sa e y, and associa ed expenses
(Bauch e al., 2003). Mo eo e , he ole o social in luence is ecognized as pi o al, as
indi iduals' decisions a e in luenced by hei in e ac ions wi h o he s. By inco po a ing
Na iga ing he nexus o COVID-19 accina ion s a egies: insigh s beyond he needle
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social in luence in o accina ion models, esea che s can gain aluable insigh s in o he
unde lying mechanisms shaping accina ion choices and de elop in e en ions o
enhance accine up ake19-21. By adop ing a dual-pe spec i e app oach ha conside s bo h
cos s and social in luence, a comp ehensi e unde s anding o accina ion decision-
making can be a ained. Such unde s anding se es as a guide o o mula ing s a egies
aimed a imp o ing accine accep ance and co e age (Xia and Liu, 2013; Jianwei e al.,
2020; Bish e al., 2011).
This s udy is mo i a ed by he ecogni ion o he signi ican in luence o human
beha io in he in ica e in e play be ween accina ion, social en i onmen s, and public
policies. Ou p ima y objec i e is o examine he epe cussions o COVID-19 policies on
indi iduals' decision-making p ocesses ega ding accina ion. To o e a comp ehensi e
e alua ion o hese policies, we cons uc a heo e ical model ha inco po a es wo c ucial
elemen s: indi iduals' pe cep ions o accina ion cos s and he impac o social ac o s.
By aking hese aspec s in o accoun , ou aim is o enhance ou unde s anding o how
policies shape indi iduals' choices ega ding accina ion and o gene a e insigh s in o
e ec i e s a egies o p omo ing accine accep ance.
Model
In ou s udy, we di ec ou a en ion o a well-mixed popula ion and del e in o he
con ex o a singula epidemic ou b eak, such as he COVID-19 pandemic. Unlike
seasonal diseases, whe e knowledge and expe ience can accumula e o e ime, in his
pandemic scena io, accina ion becomes a one- ime decision ha indi iduals mus make.
We assume ha cos s and p obabili ies associa ed wi h accina ion can be es ima ed based
on indi idual pe cep ions, which may a y om pe son o pe son. The ini ial phase o
ou in es iga ion is cen e ed on conduc ing a comp ehensi e cos analysis o accina ion
decisions.
Di e gen Choices, Sha ed Conce ns: Unde s anding accina ion decision
pe spec i es
On a i s s age, acing an epidemic ou b eak, an indi idual i ini ially pe cei es he
cos s associa ed wi h ge ing in ec ed as 𝐶𝑖𝑖𝑛𝑓, encompassing heal hca e expenses, los
p oduc i i y, and po en ial pain o mo ali y. Addi ionally, hey assess a p obabili y o
con ac ing he disease, deno ed as 𝛽𝑖. The indi idual's expec ed in ec ion cos , based on
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hei pe cep ion, can be calcula ed as 𝛽𝑖𝐶𝑖𝑖𝑛𝑓. The second s age in ol es he in oduc ion
o he possibili y o ge accina ed h ough a olun a y accina ion campaign, whe e
indi iduals decide whe he o ge accina ed o no . Gi en he a ailable in o ma ion, an
indi idual, deno ed as i, o ms an es ima ion o he cos s associa ed wi h accina ion,
which includes pe cei ed cos s deno ed as 𝐶𝑖𝑉𝑎𝑐. We de ine accine cos s b oadly,
including bo h di ec cos s and an icipa ed isks. These cos s include immedia e mone a y
expenses, oppo uni y cos s ela ed o he ime and incon enience o accine
adminis a ion, and po en ial ad e se heal h e ec s as pe cei ed by he indi idual. To
accoun o he possibili y o impe ec accina ion, indi iduals can s ill con ac he
disease a e ecei ing he accine, wi h a p obabili y deno ed as 𝛽𝑖𝑣𝑎𝑐. Taking all hese
ac o s in o conside a ion, he o al pe cei ed cos s o ge ing accina ed o an indi idual
i can be exp essed as: 𝐶𝑖𝑉𝑎𝑐 +𝛽𝑖𝑣𝑎𝑐𝐶𝑖𝑖𝑛𝑓.
When making he decision o ge accina ed o no , indi iduals weigh he ela i e
cos s o wo op ions based on hei pe cep ion. They can ei he bea he cos s associa ed
wi h e using he accine, which can be ep esen ed as 𝛽𝑖𝐶𝑖𝑖𝑛𝑓 , o choose o ge
accina ed, wi h o al pe cei ed cos s gi en by: 𝐶𝑖𝑉𝑎𝑐 +𝛽𝑖𝑣𝑎𝑐𝐶𝑖𝑖𝑛𝑓. The e o e, we exp ess
he pe cei ed cos s o he indi idual i’s choice 𝐶𝑖 as ollows:
𝐶𝑖={ 𝐶𝑖𝑉𝑎𝑐 +𝛽𝑖𝑣𝑎𝑐𝐶𝑖𝑖𝑛𝑓 𝑎𝑐𝑐𝑒𝑝𝑡𝑎𝑛𝑐𝑒 𝑜𝑓 𝑣𝑎𝑐𝑐𝑖𝑛𝑎𝑡𝑖𝑜𝑛
𝛽𝑖𝐶𝑖𝑖𝑛𝑓 𝑅𝑒𝑗𝑒𝑐𝑡𝑖𝑜𝑛 𝑜𝑓 𝑣𝑎𝑐𝑐𝑖𝑛𝑎𝑡𝑖𝑜𝑛
To simpli y he cos unc ion wi hou losing gene ali y, we in oduce he cos a io
be ween 𝐶𝑖𝑖𝑛𝑓and 𝐶𝑖𝑉𝑎𝑐. This can be deno ed as: 𝑟𝑖𝑉= 𝐶𝑖𝑉𝑎𝑐
𝐶𝑖𝑖𝑛𝑓. Thus, he decision o accep
accina ion occu s when he cos o ge ing accina ed is lowe han he cos o no
ecei ing he accine, o i he ixed cos a io o accina ion is lowe han he di e en ial
o he isk o in ec ion wi hou he accines: 𝑟𝑖𝑉<𝛽𝑖−𝛽𝑖𝑣𝑎𝑐. In his case, he cos s o
ge ing accina ed can be exp essed as: 𝐶𝑖=𝐶𝑖𝑉𝑎𝑐 +𝛽𝑖𝑣𝑎𝑐𝐶𝑖𝑖𝑛𝑓. The ejec ion o
accina ion would ansla e o a cos o ge ing accina ed ha is highe han he cos o
no ge ing he sho : 𝑟𝑖𝑉>𝛽𝑖−𝛽𝑖𝑣𝑎𝑐, and a cos o no ge ing accina ed o 𝛽𝑖𝐶𝑖𝑖𝑛𝑓.
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In he case whe e he cos s o bo h op ions a e equal, an indi idual would be
indi e en in choosing ei he o ge accina ed o no , and is mo e likely o no ge
accina ed due o he omission bias. As a consequence, he decision o no ge ing
accina ed is aking unde he condi ion: 𝑟𝑖𝑉≥𝛽𝑖−𝛽𝑖𝑣𝑎𝑐.
𝐶𝑖={ 𝐶𝑖𝑉𝑎𝑐 +𝛽𝑖𝑣𝑎𝑐𝐶𝑖𝑖𝑛𝑓 𝑖𝑓 𝑟𝑖𝐹𝑖𝑥 <𝛽𝑖−𝛽𝑖𝑣𝑎𝑐
𝛽𝑖𝐶𝑖𝑖𝑛𝑓 𝑖𝑓 𝑟𝑖𝐹𝑖𝑥 ≥𝛽𝑖−𝛽𝑖𝑣𝑎𝑐
We in oduce he a iable 𝛾𝑖 o ep esen an indi idual's accina ion op ions.
The e a e wo possible decisions an indi idual can make: 𝛾𝑖=1 co esponds o accep ing
accina ion, while 𝛾𝑖=0 ep esen s ejec ing i . Taking in o conside a ion his pa ame e ,
we can w i e he cos s unc ions as ollows: 𝐶𝑖𝛾𝑖=𝛾𝑖[𝐶𝑖𝑉𝑎𝑐 +𝛽𝑖𝑣𝑎𝑐𝐶𝑖𝑖𝑛𝑓]+(1−
𝛾𝑖)𝛽𝑖𝐶𝑖𝑖𝑛𝑓, whe e: 𝐶𝑖1=𝐶𝑖𝑉𝑎𝑐 +𝛽𝑖𝑣𝑎𝑐𝐶𝑖𝑖𝑛𝑓 and 𝐶𝑖0=𝛽𝑖𝐶𝑖𝑖𝑛𝑓. Based on he pe cei ed
cos s and p obabili ies associa ed wi h bo h choices o an indi idual i, we can exp ess he
cos -minimized choice in he ollowing manne :
𝛾𝑖={ 1 𝑖𝑓 𝑟𝑖𝐹𝑖𝑥 <𝛽𝑖−𝛽𝑖𝑣𝑎𝑐 𝑜𝑟 𝑎𝑐𝑐𝑒𝑝𝑡𝑎𝑛𝑐𝑒 𝑜𝑓 𝑣𝑎𝑐𝑐𝑖𝑛𝑎𝑡𝑖𝑜𝑛
0 𝑖𝑓 𝑟𝑖𝐹𝑖𝑥 ≥𝛽𝑖−𝛽𝑖𝑣𝑎𝑐 𝑜𝑟 𝑅𝑒𝑗𝑒𝑐𝑡𝑖𝑜𝑛 𝑜𝑓 𝑣𝑎𝑐𝑐𝑖𝑛𝑎𝑡𝑖𝑜𝑛
Figu e 1: The accina ion beha io based on he combina ion o he pe cei ed cos s and p obabili ies o
in ec ion o an indi idual i. The g aph a on he le depic s he indi e ence be ween he wo op ions o
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ge ing accina ed o no . On he igh , he g aph b illus a es he ai o accina ion accep ance: 𝑟𝑖𝑉<
𝛽𝑖−𝛽𝑖𝑣𝑎𝑐
I all indi iduals adop he same s a egy o minimizing hei cos unc ions, hey will each a s eady s a e
whe e no indi idual has an incen i e o change hei accina ion decision. The g aphical ep esen a ion in
Figu e-1-a, isually illus a es he highligh ed su ace whe e indi iduals a e indi e en be ween ge ing
accina ed o no . The igu e Figu e-1-b depic s he egion whe e he accina ion op ion becomes he less
cos ly choice.
2. The Ripple E ec : Explo ing social in luences on accina ion choices
In he s age o a olun a y accina ion p og am, indi idually cen e ed decisions a e
cons uc ed h ough a pe cei ed cos analysis as de ined p e iously, hose decisions a e
in luenced by hei social associa ion. In ac , whe he o no o op o he accina ion
decision depends no only on he indi idual cos s assessmen o each choice, bu also on
he pe cei ed beha io o o he s (Nde o Mbah e al., 2012). In his sec ion, social
p essu e among he popula ion is conside ed o cla i y i s impac on he decision-making
p ocess o accina ion. We deno e 𝑆𝑖 he social g oup neighbo ing o indi idual i, e e y
indi idual i ind hemsel es neighbo ing a numbe o indi iduals 𝑁𝑖 in a ious social
se ings. Each indi idual i has 𝑁𝑖 neighbo s 𝑘∈𝑁𝑖 in hei social g oup, whose
accina ion decisions a e ep esen ed by 𝛾𝑖,𝑘, whe e 𝛾𝑖,𝑘 =1 indica es i obse es
accina ion o membe k and 𝛾𝑖,𝑘 =0 indica es i obse es e usal o membe k.
The a e age accina ion up ake in i's neighbo hood, as pe cei ed by he indi idual
i, is:
𝛾𝑖=∑𝛾𝑖,𝑘
𝑁𝑖
𝑘=1
𝑁𝑖
To assess he p obabili y o an indi idual shi ing hei decision o ha o he
majo i y, we use he Fe mi unc ion (Fu e al., 2011). I is a sigmoid unc ion ha has been
widely used o desc ibing how indi iduals’ beha io al changes as a esponse o he
disc epancy be ween wo di e en choices. The pa ame e 𝜙𝑖 illus a es he sensi i i y o
indi iduals o he choice di e ence om hei social neighbo hood; he e o e, a highe 𝜙𝑖
ansla es o a highe esponsi eness, and an indi idual being mo e sensi i e o he
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di e ence. In his case, a shi o he ini ial op imal decision 𝛾𝑖 is mo e likely o occu , o
app oach ha o majo i y o he g oup membe s. The p obabili y 𝑝𝑖(𝑖←𝑆𝑖) o copying
he g oup’s s a egy is gi en by:
𝑝𝑖(𝑖←𝑆𝑖)=1
1 + exp {−𝜙𝑖|𝛾𝑖− 𝛾𝑖|}
Hence, we de ine 𝑝𝑖(𝑖←𝑆𝑖) as he p obabili y o an indi idual swi ching hei
decision o copy ha o he majo i y made by hei neighbo s. The e will be a shi o he
indi idual op imal decision 𝛾𝑖 wi h a p obabili y 𝑝𝑖(𝑖←𝑆𝑖), and wi h a p obabili y (1 −
𝑝𝑖(𝑖←𝑆𝑖)), he indi idual is going o keep he less cos ly decision 𝛾𝑖. 𝑝𝑖(𝑖←𝑆𝑖)=0
co esponds o he case o a cos -based decision make , whe eas 𝑝𝑖(𝑖←𝑆𝑖)=1 indica es
ha he indi idual is an absolu e social ollowe . Consequen ly, he cos s unc ion would
be as ollows:
𝐶𝑖𝛾𝑖= 𝑝𝑖(𝑖←𝑆𝑖)𝐶𝑖𝑆𝑜𝑐𝑖𝑎𝑙 +(1−𝑝𝑖(𝑖←𝑆𝑖))𝐶𝑖𝐼𝑛𝑑𝑖𝑣𝑖𝑑𝑢𝑎𝑙
whe e:
𝐶𝑖𝑆𝑜𝑐𝑖𝑎𝑙 =|𝛾𝑖− 𝛾𝑖| ep esen s he implici cos o de ia ing om he g oup no m.
𝐶𝑖𝐼𝑛𝑑𝑖𝑣𝑖𝑑𝑢𝑎𝑙 is he indi idual’s cos based on hei pe sonal decision (as de i ed in he
p e ious sec ion).
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Figu e 2: The g aph depic s he pe cei ed gap be ween he a e age social choice o he g oup and he
indi idual’s op imal choice, and he p obabili y o he indi idual o shi hei decision o ha o he
majo i y o hei social g oup. The impac is also in luenced by he esponsi eness o he choice
disc epancy, he e we illus a e di e en le els o 𝜙𝑖.
In igu e 2, he g aph illus a es he ela ionship be ween he di e ence |𝛾𝑖− 𝛾𝑖|
and he p obabili y o indi iduals con empla ing a change in hei s a egy by adop ing he
op ion closes o he g oup's a e age. As his di e ence inc eases, he likelihood o an
indi idual econside ing hei op imal choice 𝛾𝑖 and op ing o a s a egy close o he
a e age o he g oup also ises. The exis ence o such a disc epancy ac s as a ca alys ,
p omp ing indi iduals o eassess hei decisions and con empla e adop ing an al e na i e
ha b ings hem in line wi h he collec i e. Mo eo e , he p obabili y o indi iduals op ing
o he op ion closes o he g oup a e age is addi ionally in luenced by 𝜙𝑖, hei le el o
esponsi eness. Indi iduals wi h highe esponsi eness exhibi a g ea e inclina ion o
adjus hei decisions and align hem wi h he choices made by he g oup. This means ha
indi iduals who a e mo e esponsi e o he ac ions and p e e ences o he g oup a e mo e
likely o adop s a egies ha mi o he collec i e decision-making p ocess. I is clea ha
plugging in o he social p essu e wo ks as a “double-edged swo d”, which, on he one
hand, p omo es accine up ake in he popula ion when i ’s he up ake o aking a sho is
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he less cos ly op ion. Fo he accina ion op ion o be he op imal one, he applied es ’s
cos s should co e he pe cei ed cos s o accina ion ela i ely o he op ion o no ge ing
he sho , while aking in o accoun how he in o ma ion is ansla ed om indi idual o
ano he , and he possibili ies o he cos s discoun du ing he pe iod o applica ion.
These indings emphasize he signi icance o clea and e ec i e communica ion
om au ho i ies ega ding he du a ion o manda o y es ing equi emen s. I is c ucial o
p o ide anspa en in o ma ion abou he ime ame du ing which es ing will be
necessa y. This anspa ency is i al as i indi iduals pe cei e he es ing pe iod o be
sho e , hey may be mo e inclined o conside equen es ing as a iable al e na i e o
accina ion. This pe cep ion can subsequen ly educe hei willingness o ge accina ed.
By ensu ing ha indi iduals ha e a clea unde s anding o he es ing equi emen s
and he po en ial du a ion, au ho i ies can assis indi iduals in mo e accu a ely weighing
he cos s and bene i s o accina ion e sus es ing.
Tackling o ge y, illici ac i i ies, and accina ion:
Ano he op ion ha we assumed o be a ailable is ha o o ged documen s. The
coun e ei ce i ica es ha e a ixed cos 𝐶𝐹𝑎𝑘𝑒, and a ine 𝑓𝐹𝑎𝑘𝑒 is applicable depending
on he p obabili y o de ec ion 𝑝𝑖𝐹𝑎𝑘𝑒: 𝐶𝐹𝑎𝑘𝑒 +𝑝𝑖𝐹𝑎𝑘𝑒𝑓𝐹𝑎𝑘𝑒. We exp ess he cos s
compa ison in e ms o a io ela i ely o he ine o he es :
𝛽𝑖𝐶𝑖𝑖𝑛𝑓 +𝐶𝑇𝑒𝑠𝑡[𝑙𝑛(𝑇𝑖)+𝛾]<𝛽𝑖𝐶𝑖𝑖𝑛𝑓 +𝐶𝐹𝑎𝑘𝑒 +𝑝𝑖𝐹𝑎𝑘𝑒𝑓𝐹𝑎𝑘𝑒
O : 𝑟𝐹𝑎𝑘𝑒 >𝑟𝑇𝑒𝑠𝑡/𝐹𝑖𝑛𝑒[𝑙𝑛(𝑇𝑖)+𝛾]−𝑝𝑖𝐹𝑎𝑘𝑒 whe e: 𝑟𝐹𝑎𝑘𝑒 =𝐶𝐹𝑎𝑘𝑒
𝑓𝐹𝑎𝑘𝑒 and 𝑟𝑖𝑇𝑒𝑠𝑡 =𝐶𝑇𝑒𝑠𝑡
𝑓𝐹𝑎𝑘𝑒
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Figu e 4: he a ea depic ed in he g aphs is 𝑟𝐹𝑎𝑘𝑒 =𝑟𝑇𝑒𝑠𝑡/𝐹𝑖𝑛𝑒[𝑙𝑛(𝑇𝑖)+𝛾]−𝑝𝑖𝐹𝑎𝑘𝑒. Fo any
combina ion o cos s and p obabili ies ha is highe han he h eshold, he indi idual i will ind i less
cos ly o acqui e a nega i e es . I depic he changes ha occu i he indi idual pe cei ed di e en
nega i e es pe iod om 0 o 20, and h ee le els o p obabili y o de ec ion o he illici ac i i y.
The p esen ed g aphs in Figu e 4 illus a e how a change in pe cep ion ega ding
he p obabili y o de ec ion can signi ican ly in luence he ou come o he accina ion
decision-making p ocess. This emphasizes he c ucial ole o e ec i e communica ion
ega ding measu es aimed a cu bing he use o o ged documen s. To add ess his issue,
i is essen ial o communica e he po en ial ami ica ions o acqui ing illegal documen s,
while also conside ing indi iduals' endencies o discoun u u e consequences and hei
a ying pe cep ions o he ime ame du ing which nega i e es esul s emain alid.
Regula o s should implemen ines ha app op ia ely e lec he di e en le els o
i e a ions and p obabili ies pe cei ed by indi iduals. Fu he mo e, b oadcas ing
in o ma ion abou he po en ial legal consequences o u ilizing coun e ei ce i ica es can
se e as a de e en o hose who migh con empla e engaging in such ac i i ies. By aking
hese s eps, au ho i ies can wo k owa ds mi iga ing he p oblem and discou aging
indi iduals om pa icipa ing in audulen p ac ices.
7. Discussion
A ho ough comp ehension o indi iduals' beha io when i comes o making
heal h decisions plays a pi o al ole in an icipa ing he po en ial consequences o policies
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aimed a imp o ing accina ion accep ance a es. The p ocess o decision making in his
con ex elies on indi iduals' pe sonal belie s, which shape hei pe cei ed pa ame e s.
Consequen ly, policymake s should e ec i ely communica e he pe inen de ails ha
enable indi iduals o upda e hei in o ma ion ega ding associa ed cos s and ime ames.
By doing so, policymake s can acili a e a mo e in o med decision-making p ocess,
ul ima ely os e ing g ea e accep abili y o accina ion and enhancing public heal h
ou comes. To p e en di e gence ha migh occu a e he applica ion o any policy, he
in e en ions ha would encou age accina ion should be communica ed clea ly o
p e en possible empo al discoun ing, as well as he consequences o any illegal ac i i ies
discou aged h ough con eying he app op ia e ines.
S eng hs and Limi a ions
Va ious ma hema ical models ha e employed payo -based app oaches o
unde s and indi iduals' accina ion decisions, conside ing pe cei ed cos s and bene i s
(Chen, 2006; Codeço e al., 2007; Va da as e al., 2007). As an ad ancemen o e exis ing
models, we p opose conside ing an indi idual's accina ion decision as a hyb id p ocess
ha inco po a es bo h sel -ini ia ed cos minimiza ion and he in luence o social g oup’s
a e age decision. Ou s udy in oduces a comp ehensi e modeling amewo k ha
inco po a es social ac o s in o indi iduals' decision-making p ocesses, speci ically
ocusing on unde s anding accina ion policies and hei unde lying mechanisms o
in luence. Howe e , i is c ucial o acknowledge ha he indings o his s udy may be
in luenced by he pa icula social ne wo k conside ed. Like any model, ou app oach also
necessi a ed making ce ain simpli ying assump ions. Fu he mo e, i is impo an o
acknowledge ha ou esea ch assumes indi iduals o be passi e ecipien s o social
in luence, and we ha e no explici ly conside ed hei ac i e beha io s in ou analysis.
These assump ions p o ide a ounda ion o ou model bu should be ecognized as
po en ial limi a ions in unde s anding he ull complexi y o indi iduals' decision-making
p ocesses.
8. Conclusions
The policies employed in inci ing indi iduals o ge ing accina ed du ing he
COVID-19 pandemic we e p ima ily s a egies ha impac ed he cos s. E en hough
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inc easing he cos s o he e usal o eluc ance in ge ing accina ed migh encou age
indi iduals o ge he sho , hose policies do no aim in changing he pe cep ions a ound
he a es o in ec ion o he cos s o any o he decisions o ge ing accina ed o no . The
in e en ion migh be e ec i e in eaching head immuni y, and s opping he sp ead o
he disease, howe e , au ho i ies migh ace he same social eac ions in case ano he
heal h c ises migh hi in he u u e. A long- e m emedy o accina ion hesi ancy migh
be an es ablishmen o channels o in o ma ion ansmission, ha would con inuously
ad ise and cla i y misconcep ions and doub s a ound accines in pa icula , and heal h
ela ed ques ions in gene al. Educa ional p og ams migh also con ibu e in he inc ease
o indi iduals’ con idence in public heal h managemen , imp o e he ela ionship be ween
policymake s and scien i ic and echnical bodies, and inc ease anspa ency o e he use
o medical da a collec ed wi hin he popula ion.
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