VacciCost – A tool to estimate the resource requirements for implementing livestock vaccination campaigns. Application to peste des petits ruminants (PPR) vaccination in Senegal

ContentslistsavailableatScienceDirect

Preventive

Veterinary

Medicine

jou rn al h om ep a g e :w w w . e l s e v i e r . c o m / l o c a t e / p r e v e t m e d

VacciCost

–

A

tool

to

estimate

the

resource

requirements

for

implementing

livestock

vaccination

campaigns.

Application

to

peste

des

petits

ruminants

(PPR)

vaccination

in

Senegal

Damian

Tago

_,

_Baba

_Sall

_,

_Renaud

_Lancelot

_,

_Jennifer

_Pradel

a_{FrenchAgriculturalResearchforDevelopment(CIRAD),UnitAnimals,Health,Territories,RisksandEcosystems(ASTRE),97170,Petit-Bourg,Guadeloupe,}

France

b_{FrenchNationalInstituteforAgriculturalResearch(INRA),UnitASTRE,34398,Montpellier,France} c_{DirectiondesServicesVétérinaires,BP45677,Dakar,Senegal}

d_{CIRAD,UnitASTRE,34398,Montpellier,France}

a

r

t

i

c

l

e

i

n

f

o

Articlehistory: Received16June2016

Receivedinrevisedform9May2017 Accepted10May2017

Keywords: Vaccination Costassessment Pestedespetitsruminants Senegal

a

b

s

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Vaccinationisoneofthemaintoolscurrentlyavailabletocontrolanimaldiseases.Ineradication cam-paigns,vaccinationplaysacrucialrolebyreducingthenumberofsusceptiblehostswiththeultimategoal ofinterruptingdiseasetransmission.Nevertheless,massvaccinationcampaignsmaybeveryexpensive andinsomecasesunprofitable.VacciCostisatooldesignedtohelpdecision-makersintheestimationof theresourcesrequiredtoimplementmasslivestockvaccinationcampaignsagainstregulateddiseases. Thetoolfocusesontheoperationalorrunningcostsofthecampaign,soacquisitionofnewequipment orvehiclesisnotconsidered.Ittakesintoaccountdifferenttypesofproductionsystemsto differenti-atethevaccinationproductivity(numberofanimalsvaccinatedperday)insystemswhereanimalsare concentratedandeasytoreach,fromthosecharacterizedbysmallherdsthatarescatteredandless acces-sible.Theresourcerequirementsareclassifiedineightcategories:vaccines,injectionsupplies,personnel, transport,maintenanceandoverhead,training,socialmobilization,andsurveillanceandmonitoring.This categorizationallowsidentifyingthemostexpensivecomponentsofavaccinationcampaign,whichis crucialtodesigncost-reductionstrategies.Theuseofthetoolisillustratedusingdatacollectedin col-laborationwithSenegaleseVeterinaryServicesregardingvaccinationagainstpestedespetitsruminants. Theaveragedailynumberofanimalsvaccinatedpervaccinationteamwasfoundtobecrucialforthe costsofthecampaignsosignificantsavingscanbeobtainedbyimplementingtrainingtoimprovethe performanceofvaccinationteams.

©2017Centredecooperationinternationaleenrechercheagronomiquepourledeveloppement (CIRAD).PublishedbyElsevierB.V.ThisisanopenaccessarticleundertheCCBY-NC-NDlicense(http:// creativecommons.org/licenses/by-nc-nd/4.0/).

1. Introduction

Animal vaccination is usually considered as a cost-effective

methodtopreventanimaldisease,enhancetheefficiencyoffood

production,andprotecthumanhealthbyreducingtheriskof

trans-missionof zoonotic and foodborne pathogens from animalsto

people(Roth,2011;ShimshonyandEconomides,2006).Therole

ofvaccinationhasbeencrucialineradicatingrinderpest,thefirst

animaldiseasetobeeradicatedglobally(Marineretal.,2012).Also,

∗ Corresponding authorsat: FrenchAgricultural Research forDevelopment (CIRAD),UnitAnimals,Health,Territories,RisksandEcosystems(ASTRE),Domaine deDuclos,Prised’eau,Petit-Bourg,97170,Guadeloupe,France..

E-mailaddresses:dtagop@gmail.com(D.Tago),jennifer.pradel@cirad.fr (J.Pradel).

vaccinationcangreatlyreducethepotentialofmajorepidemics

(Keelingetal.,2002).

High-riskcountries,i.e.disease-freecountriessurroundedby

areasinwhichthediseaseispresent,orcountriesimporting

ani-malsfromendemicareas,mayuseanimalvaccinationtoprotect

theirnationalstocksinceotherstrategiessuchassurveillance

asso-ciatedwithstamping-outcanbetoocostlyanddisruptive(Horst

etal.,1999;ShimshonyandEconomides,2006).Tobesuccessful,

vaccinationcoveragehastobehighenoughtodecreasethenumber

ofsusceptibleanimalstosufficientlylowlevelssuchthatdisease

transmissionisinterrupted(Woolhouseetal.,1996).

Moreover,veterinaryvaccinesareofparticularinterestinthe

contextofgrowingconcernsrelatedtoantimicrobialresistanceas

theycontributeinsomecasestodecreaseduseofantibioticsby

pre-ventinginfectionsinfoodproducingandcompanionanimals(Roth,

http://dx.doi.org/10.1016/j.prevetmed.2017.05.011

0167-5877/©2017Centredecooperationinternationaleenrechercheagronomiquepourledeveloppement(CIRAD).PublishedbyElsevierB.V.Thisisanopenaccessarticle undertheCCBY-NC-NDlicense(http://creativecommons.org/licenses/by-nc-nd/4.0/).

2011).Inthecaseoflivestock,whenvaccinationisconsideredas

apublichealthpolicy,fundedbypublicresources,consideringits

costiscrucialtoproperlyevaluateitseffectivenessandensurea

favorablecost-benefitratio.

1.1. RationaleofatoollikeVacciCost

Nationalauthorities frequentlyhave toallocateresourcesto

reachthesocially–aswellasepidemiologically,optimalvaccination

coverageduetothepositiveexternalities(benefitsgeneratedbyan

activitythatareexperiencedbyunrelatedthirdparties)associated

withvaccinating(McLeodandRushton,2007).

Apossiblestrategytoeliminateadiseasefromaninfectedarea

andtostopthetransmissionofthecausativepathogenagentis

toimplementsuccessiveannualmassvaccinationcampaigns.The

goalistovaccinateoverashortperiodoftimeaveryhigh

propor-tionofthetargetpopulation,definedasthesubsetofthegeneral

susceptibleandimmunologicallycompetentpopulation(i.e.atrisk

ofinfectionandabletoproduceanimmuneresponseaftervaccine

administration).

Toproperlyand objectivelyanalyzethepossibility of

imple-mentingmassvaccinationcampaignsfinancedorco-financedby

publicfunds,nationalauthoritiesandfundingagenciesneed

accu-rate estimates of the vaccination cost. A tool providing such

estimatesisusefulforseveralreasons:

ex-anteassessmentoftheviabilityandcost-effectivenessofa

massvaccinationcampaign;

assistancefor preparing budgets, especially ifthe campaign

involvesbothgovernmentalresourcesandcomplementary

finan-cialsupportbyinternationalorganizations;

comparisonof differentvaccinationstrategies,dependingon

theavailabilityof resourcesand thedurationof thevaccination

program.

Additionally,attheindividuallevel,thedecisiontovaccinate

resultsfromanempiricalevaluationoftheexpectedbenefitsof

immunizinganimalsagainstthecoststhatvaccinationrepresents

forthefarmers,basedontheindividuals’knowledgeand

percep-tionofthediseaserisk.Insomecases(diseaseabsentfromtheir

herdandneighborhood,lowprevalence,littleimpact...),the

per-ceivedriskofinfectionisnothighenoughtomakethemdecideto

vaccinatetheirherds.Therefore,ifthediseasespreadposesapublic

healthrisk,subsidizingschemesmightbenecessarytoencourage

livestockownerstovaccinateandreachtheobjectiveintermsof

immunitycoverage(Gethmannetal.,2015).

1.2. Controlanderadicationprograms

Control,and afortiorieradication,of animaldiseases froma

givenareagenerallyinvolvesalotofresourcesandcoordination

efforts.Estimatingthecostsassociatedwithdiseasecontrolor

erad-ication,includingvaccination,iscrucialduringtheplanningprocess

andforseekingadequateandsufficientfundingtoensuresuccess

oftheprogram.Underestimatingthecostscanleadto

inappropri-ateimplementationofvaccinationhencenegativelyimpactingthe

immunizationcoverageandgivingopportunitiesforthepathogen

tosurvive;ontheotherhand,overestimatingthecostscan

discour-agedecisionmakersfrominvestinginthecontroloreradication

campaign.

ThispaperpresentsVacciCost,a tooldevelopedtohelp

esti-matingtheresource requirementstoimplement masslivestock

vaccinationcampaigns, aswellas acase study usingfield data

collectedinSenegalonthevaccinationcostsforpestedespetits

ruminants(PPR),amajorinfectiousviraldiseaseofsheepandgoats

widespreadinAfrica,theMiddleEast,andAsia(Baronetal.,2016).

AglobalPPRcontrolanderadicationstrategyhasbeendeveloped

bytheFoodandAgricultureOrganizationoftheUnitedNations

(FAO)andtheWorldOrganisationforAnimalHealth(OIE)(OIEand

FAO,2015;Rajetal.,2015).Differentscenariosareconstructedto

estimatetheresourcerequirementsassociatedwithPPR

vaccina-tion.

Inthefollowingsections,theVacciCosttoolisdescribedindetail

alongwiththedatarequiredtouseit.Thedatacollectedin

col-laborationwithSenegaleseDirectorateofVeterinaryServicesare

describedandscenariosreflectingdifferentvaccination

productiv-itylevels(numberofanimalsvaccinatedperdaypervaccination

team)areconstructedtoassesstheinfluenceofsomeparameters

onthecostevaluation.Next,resultsarepresentedanddiscussed,

aswellasthetool’slimitations.

2. Methodology

2.1. VacciCostdescription

VacciCost was developed following the same cost structure

astheWorldHealthOrganization(WHO)guidelinestoconstruct

comprehensive multiyear plans (cMYP) for human

immuniza-tionprograms(WorldHealthOrganization,2006), adaptingitto

the livestock sector and structured for a single year period. It

focusesontheoperationalorrunningcosts–excludingthe

cap-italcostsassociatedwithgoodsthatarenotconsumedorreplaced

everyyearsuchasthecold-chainequipmenttostorethevaccine

beforeitsuse, vehiclesor buildings.Thetool wasdeveloped in

anExcel® _{spreadsheet(MicrosoftCorp.)anditsproper}

function-ingrequiresinstallingtheopensourceOpenPERTMicrosoftExcel

‘add-in’(https://code.google.com/archive/p/openpert/).

Theflexibilityofthetoolallowsitsuseforestimatingthecostof

vaccinationcampaignsagainstanylivestockdiseaseandfor

live-stock sectors characterizedby two contrasted farming systems

withstructuraldifferences thataffecttheeasewithwhich

live-stockarereached:productionsystemswhereanimalsarereared

in small flocks (“backyard” or “mixed crop-livestock” systems)

versusproductionsystemswhereanimalsarerearedinbiggerherds

(“industrial”or “pastoral” systems). Resource requirementsare

estimatedtakingasinputtheavailabilityofhumanresources(in

numberofvaccinationteams)andreturningthelengthofthe

vac-cinationcampaign(indays),orviceversa.Fixedcosts,including

capitaldepreciation(vehicles,buildings,etc.),arenotincludedin

thistool.Iftheobjectiveistoestimatethetotalcostofvaccination

(operationalandfixedcosts),theresultsofVacciCostneedtobe

complementedtocapturethefixedcomponent.

2.2. Costcomponents

The resource requirements are computed according to the

following components: vaccines,injection supplies,staff,

trans-port,maintenanceandoverhead,training,socialmobilization,and

surveillanceandmonitoring.Additionalincentivestoincreasethe

farmers’ willingness to vaccinate (such as monetary incentives

or free deworming while vaccinating)can beconsidered when

needed.Table1summarizesthedatarequiredasinputforeach

component.

Theproductivityofvaccinationteamsisacrucialparameterfor

thecostestimation.However,itisnoteasytoestimate.Toaccount

foritsuncertainty,productivityofvaccinationteamsisconsidered

asarandomvariabledescribedbyaPERTdistribution.The

parame-tersofsuchdistributionaretheminimum,maximum,andthemost

likelyvalue;a95%confidenceintervalcanbecomputedaroundthe

averagecost.

Vaccinating small flocks (i.e. backyard production or

small-holdermixedcrop-livestocksystemsin developingcountries)is

mea-Table1

InputdataforVacciCost.

Category Datarequired

Population&vaccinationcoverage -Livestockpopulation(numberofanimals) -Coveragetarget(%) -Livestockpopulationbyproductionsystem

1.Vaccines -Numberofdosesperanimal -Freight&handlingcharges(as%ofmarketprice) -Priceperdose(USD) -Wastagerate(%)

2.Injectionsupplies -Costofinjectionsuppliesperdose(USD) -Wastagerate(%) -Freight&handlingcharges(USD)

3.Personnel -Compositionofavaccinationteam(number ofvets,drivers,supportingstaff)

-Lengthofcampaign(months)Ornumberofteamsavailable -Wagesperhour(USD) -Teamproductivity(numberofanimalsvaccinated)eachdayperteam) -Numberofdailyworkinghours -Monthlyperdiemsandfinancialincentives(USD)

4.Transport -Numberofvehiclesperteam -Averagefuelprice(USD/Liter)

-Averagedistanceperday(km) -Costofmaintenance(%offuelconsumption) -Vehicles’fuelefficiency(km/liter) -Othertransportationexpensesperteam(USD) 5.Maintenance&overhead -Numberandcostofcoldchainequipmentper

team(units&USD)

-Othermonthlyoverheads(electricitybills,etc.)(USD) -Costofmaintenance(%ofequipmentvalue)

6.Training -Hourlycostoftrainingperperson(USD) -Numberofhoursoftrainingrequiredperagent 7.Socialmobilization -Costofsocialmobilizationactivitiesperteam

(USD)

-Costofincentivesprovidedtofarmers(USD/vaccinatedanimal)

8.Surveillance&monitoring -Unitcostofseroprevalencetest(USD) -Numberofmonthsworkedbyamonitor -Numberofteamssupervisedpermonitor -Diseaseprevalencetobedetected -Monthlywageofmonitor(USD) -Confidencelevelforsamplesizecalculation

suredbytheaveragenumberofanimalsvaccinatedperteamper

day.Asamatteroffact,inthesesystems,itisoftendifficulttogather

theanimalsfrommanysmallherds.Also,thereisalackof

infras-tructuressuchasvaccinationpens.Conversely,inpastoralandagro

pastoralsystems,whereanimalsarekeptinlargerflocks,the

pro-ductivityofvaccinationteamsisusuallymuchhigher.Therefore,

apercentage reductionintheproductivityofvaccinationteams

workingin productionsystems withsmallflocks isconsidered.

Moreover,when consideringsmallruminants(sheepandgoats)

rearedinmixedcrop-livestocksystemsofsub-humidregions,the

birthsarehomogeneouslydistributedallovertheyearandbirth

rateishigherthanindrierenvironmentthankstobetterforage

resources.Therefore, withsuchahighpopulationturnover,two

vaccinationcampaignsmustbeimplementedeachyeartomaintain

highimmunitycoverageinthesmallruminantpopulation.

Injection supplies include needles, syringes, safety boxes,

gloves,etc.Thenumberofvaccinesandinjectionsuppliesare

esti-matedbased onthelivestock population, thenumber of doses

requiredperanimal, andthecoveragetargetof thevaccination

program.Then,theproductivityofvaccinationteamsisrandomly

generatedandusedtoestimatethenumberofteamsrequiredto

implementthevaccinationcampaign(orthelengthof the

vac-cinationcampaign,incasethenumber ofteamsisfixed).Along

withtherestof theinputs, thenumberofvaccinationteamsis

usedtoestimatetheremainingcostcomponentsina

determin-isticway.Thisprocedureisrepeated300times(i.e.300drawsof

vaccinationteams’productivity)someanvalues andconfidence

intervalscanbeconstructed.Detailsontheprocedureto

calcu-latetheresourcerequirementscanbefoundintheSupplementary

materialS1(User’smanual).

VacciCostautomaticallycomputes thecosts and generatesa

reportthatsummarizeswithinasinglesheetthemainresultsfor

eachcomponentwithagraph,apiechart,andtables.Thisallows

easyidentificationofthemainsourcesofcostsinavaccination

campaignaswellasthemostexpensivecomponentsofthe

vaccina-tionstrategybeingevaluated,andfacilitatesthedesignofstrategies

seekingforfurthersavings.

2.3. DatacollectedfromSenegal

In collaboration with theNational Directorate of Veterinary

Services (DVS), we analyzed the weekly reports corresponding

tothe2012–2013livestockvaccinationcampaign.The

informa-tionavailablewasnotcompletelyexhaustiveand/ordetailed,so

itwascomplementedusingdatafromthereportoftheDCI-Food

EU-fundedactivity“VaccinesfortheControlofNeglectedAnimal

DiseasesinAfrica”(VACNADA),aprojectimplementedduringthe

2010-2011vaccinationcampaigninthenorthernregionof

Saint-Louis withtheobjective ofincreasing thevaccinationcoverage

againstPPR.

Thedistributionofthesmallruminantpopulationaccordingto

thefarmingsystemswasestimatedusing thedatabaseGridded

LivestockoftheWorld(Robinsonetal.,2014).Someinformation,

suchasstaffwages,vaccinecostandsmallruminantmarketprices,

wasobtainedduring aworkshop organizedin October 2015in

DakarandcompletedwithrequestsaddressedtotheSenegalese

InstituteforAgriculturalResearch(ISRA),whichproducesandsells

thePPRvaccine.Finally,officialsoftheDVS,aswellassome

pri-vateveterinarianswhohaveanofficialmandatetoimplementPPR

vaccinationonbehalfofDVSwereconsultedtoobtaindataonthe

productivityofvaccinationteams.Collecteddataaresummarized

inTable2.

We assumed that vaccination teams worked during eight

monthswhilepost-vaccinationevaluationteams,whosestructure

isthesameasvaccinationteams(seeTable2),workedonlyduring

thelast2monthstoassesstheeffectivenessofthePPRvaccination

campaign.

Severaldifficultiesweremetwhileestimatingtheproductivity

of vaccination teams. Firstly, in Senegal, 70% of the

vaccina-tion activities are delegated to private veterinarians. They are

supposedtoreporttheiradvancesinthevaccinationcampaign;

however,someinconsistencieswerefoundregardingthefrequency

of reporting (delayed and missing reports) leading to

difficul-ties tocomputethelevel of vaccinationproductivity.Secondly,

Table2

DatacollectedinSenegal(costsinCFAFranc(XOF)).

Variable Value Source

Exchangerate(USD/XOF) 0.0017 XE.com(valueattheendof2015) Animalpopulation

ByProductionsystem

Pastoral 8,919,581 GriddedLivestockoftheWorld(Robinsonetal.,2014) Mixedcrop-livestock 1,355,724 GriddedLivestockoftheWorld(Robinsonetal.,2014) ByAgegroup

Adults(>3months) 85% WorkshopwithVeterinaryServices

Young(<3months) 15% WorkshopwithVeterinaryServices

Vaccines

No.vaccinationcampaignsinpastoralsystem 1 WorkshopwithVeterinaryServices No.vaccinationcampaignsinmixedsystem 2 WorkshopwithVeterinaryServices

Priceperdose 30 WorkshopwithVeterinaryServices

Costofinjectionsupplies(perdose) 32 WorkshopwithVeterinaryServices

Freightandhandlingcharges 15% WHO’scMYPguidelines

Wastage 10% WHO’scMYPguidelines

Personnel

Compositionofteams

Vets 0.5 WorkshopwithVeterinaryServices

Livestocktechnicians/Assistants 2 WorkshopwithVeterinaryServices

Others 0.5 WorkshopwithVeterinaryServices

Averagemonthlywagesof:

Vets 355,000 WorkshopwithVeterinaryServices

Livestocktechnicians/Assistants 200,000 WorkshopwithVeterinaryServices

Others 80,000 WorkshopwithVeterinaryServices

Hoursworkedperday 8 WorkshopwithVeterinaryServices

Monthlyperdiems 0 WorkshopwithVeterinaryServices

Transport

Numberofvehiclesperteam 0.25 WorkshopwithVeterinaryServices Averagedistancetraveledperday(km) 100 WorkshopwithVeterinaryServices Fuelefficiencyofvehicles(km/l) 11 WorkshopwithVeterinaryServices

Fuelpriceperliter 790 WorkshopwithVeterinaryServices

Maintenanceofvehicles(%fuelused) 15% WHO’scMYPguidelines

Othertransportationexpenses(perteam) 60,500 WorkshopwithVeterinaryServices Maintenance&Overheads

Numberofsmallboxesperteam 1 WorkshopwithVeterinaryServices

Numberofbigboxes 110 WorkshopwithVeterinaryServices

Priceofsmallboxes 30,211 Senegal’scMYP

Priceofbigboxes 1,812,689 Senegal’scMYP

Maintenancecost(as%ofvalue) 5% WHO’scMYPguidelines

Training

Costof1hoftrainingperperson 5000 WorkshopwithVeterinaryServices No.hoursoftrainingrequiredperperson 8 WorkshopwithVeterinaryServices Socialmobilization

Costofsocialmobilizationperteam 136,000 WorkshopwithVeterinaryServices Surveillance&monitoring

Unitcostofseroprevalencetest 2000 Lab.Nat.d’ElevageetdeRech.Vét. Numberofteamssupervisedpermonitor 30 WorkshopwithVeterinaryServices

Monthlywageofmonitor 250,000 WorkshopwithVeterinaryServices

Activesurveillanceteams 4 WorkshopwithVeterinaryServices

Numberofmonthsworkedbysurveillanceteam 2 WorkshopwithVeterinaryServices Prevalenceexpectedtobedetected 0.001 WorkshopwithVeterinaryServices Confidencelevel(samplesizecalculation) 95% WorkshopwithVeterinaryServices

species (PPR in small ruminants, lumpy skin disease in cattle,

Africanhorsesicknessinhorses,andNewcastlediseasein

poul-try)whichareaddressedatthesametimetominimizethelogistic

costs(transportation,coldchain,staffwages...).Consequently,the

soleproductivityestimatesforPPRvaccinationdonotreflectthe

realcapacityoftheteams,whoseproductivityisunderestimated.

Thirdly,privateveterinariansaregivenspecificvaccination

objec-tivesfromtheDVSthatdependonthefinancialresourcesavailable

forthecampaign.Hence,thetargetedvaccinationcoverageis

some-timesaslowas30%oftheestimatedsmallruminantpopulation.

Tominimizethetimespentonvaccination,privateveterinarians

generallydecidetoselecttheanimalsthataretheeasiesttogather,

leadingtospuriouslyhighproductivity.

Toevaluatetheinfluenceoftheteams’vaccinationproductivity

andofthepercentagereductioninproductivityappliedto

produc-tionsystemswithsmallflocksonthevaccinationcost,wedecided

toanalyzethecostofPPRvaccinationusingfourdifferentscenarios

derivedbyvaryingtheproductivityandthepercentagereduction

appliedforsystemswithsmallflocks.Thefirsttwoscenarios(A

andB)werecharacterizedbyahighlevelofvaccination

produc-tivity–usingrespectivelytheminimum(800animals),maximum

(1,500animals),andthemostlikely(1000animals)daily

produc-tivitylevelsreportedbyprivateveterinarians,andcorresponding

totheirestimatedproductivityinproductionsystemswithlarge

flocks(pastoralsystems).ScenariosAandBdifferedaccordingto

thepercentagereductionappliedtothebaselineproductivitylevel,

lowerinscenarioA(50%)thaninscenarioB(70%).Thosevalues

werechosenafterconsultationwiththeSenegaleseDVSandprivate

veterinarians.Theothertwoscenarios(CandD)werecharacterized

byalowproductivityofvaccinationteams–withrespectivelythe

minimum(100animals),maximum(795animals)andthemost

likely(316animals)dailyproductivitylevelsasindicatedinthe

vaccinationrecordsthatwereavailableindistrictswherepastoral

systemsarepredominant.ScenarioChada50%reductionin

pro-ductivityforsmallflockswhileforscenarioD,a70%reductionwas

Thevaccinationcoverageusedintheanalysiswas80%,afigure

whichwasreachedinSenegalafterseveralyearsofmass

vaccina-tionagainstrinderpestincattle(SarrandDiop,1994).Toputthis

numberin perspective,duringthe2012–2013vaccination

cam-paigntheobjectivewastovaccinate50%ofthesmallruminants

against PPRbut only 20% wereactually vaccinated. During the

2010–2011campaign,theVACNADAprojectsuccessfullyachieved

vaccinationcoverageof86%intheSt-Louisregion(northern

Sene-gal),tobecomparedwiththenationalaverageof14%.

3. Results

TheresultsaresummarizedinTable3.Theaverageresource

requirements for undertaking 7.9 million vaccines against PPR

rangedbetweenUSD1.5millionand2.7million,dependingonthe

scenarioapplied.ScenarioAwascharacterizedbyanaverageteam

productivityof981vaccinated animalsperday,whichleadtoa

totalcostofUSD0.20persheepandgoat(95%confidenceinterval

(CI):0.18,0.21).ResultsforscenarioBweresimilar,withaslightly

lowerproductivity(943vaccinatedanimalsperteamperday)and

thesamecostpervaccinatedanimal(meancost:USD0.20per

ani-mal;95%CI:0.18,0.21).AverageteamproductivityforscenarioC

was343vaccinatedanimalsperday,withanaveragetotalcostper

vaccinatedanimalofUSD0.33(95%CI:0.24,0.52).Finally,scenario

Dwascharacterizedbyanaverageteamproductivityof331,with

anaveragetotalcostofUSD0.34pervaccinatedanimal(95%CI:

0.24,0.54).

Theresource requirementsfor thepurchaseof vaccines and

injectionsupplies represented66% of thetotal cost for

scenar-ios A and B, while for the othertwo scenarios this proportion

wasslightlylowerthan40%.Themaindifferencecamefromthe

resourcesrequiredtocoverthestaffcosts:thiscostcategory

rep-resentedlessthan30%ofthetotalcostsforscenariosAandBand

morethan50%forscenariosCandD(Fig.1).

4. Discussion

TheaveragecostpervaccinatedanimalrangedfromUSD0.20

to0.34,dependingonthescenario.The95%confidenceintervalsof

thecostpervaccinatedanimalwereUSD[0.18,0.21]andUSD[0.24,

0.54]forthescenariowiththehighest(A)andlowest(D)

produc-tivity,respectively.Someofthesefiguresareconsistentwiththe

USD[0.27,0.32]rangeusedfortheglobalstrategyforthecontrol

anderadicationofPPR(OIEandFAO,2015).InNigeria,

character-izedbyasmallershareofsmallruminantslocatedinpastoralzones

(68%)comparedtoSenegal(87%),thecostofvaccinating80%ofthe

smallruminantpopulationwasestimatedtobeNGN2572million

(USD12.922million),i.e.USD0.23peranimalvaccinated(Fadiga

etal.,2013).

Thesimilarityofthevaccinationcostsobtainedwiththe

Vacci-Costtoolusingdifferentpercentagereductionsinproductivityfor

smallflocks,eitherinhigh(USD0.20inscenarioAandB)orlow

(USD0.33andUSD0.34inscenarioCandDrespectively)

productiv-ityscenarios,showsthatthisfactorhadlittleeffectontheestimated

costofvaccinationperanimal.Indeed,inSenegalthepopulationof

smallruminantsinmixedsystemswaslessthan15%ofthetotal

smallruminantpopulation;thereforethispercentagereductionin

productivityhadnegligibletolittleinfluenceontheresults.

Incontrast,teamproductivityhadalargeeffect(differenceof

USD0.10peranimal,betweenscenarioA/BandC/D)onthe

“Per-sonnel”costcomponent,whichcapturesthelaborcostsrelatedto

vaccinationteams.Toputinperspectivetheproductivityestimates

usedin this analysis,wecancomputethecorresponding

num-berofanimalsvaccinatedperminute.Themostlikelyvaccination

team’sproductivitiesinpastoralsystemswere1000(scenariosA

andB)and316(scenariosCandD)animalsperday(8

consecu-tivehours),i.e.,2.1and0.7animalsperminuterespectively.Taking

intoaccountthetimespentintransportation,gathering,sorting,

andhandlingtheanimals,andthefactthatattheendofthe

cam-paign,the animalstovaccinate aremore difficultto reach, the

averageproductivityfiguresusedinscenariosAandBmaylook

optimistic.Overestimatingteams’productivitymayleadto

under-estimatevaccinationcosts.Giventheimportanceofthisparameter

onthecost,and theuncertaintyonitsestimates,itistherefore

recommendedthatrealisticestimatesarecarefullychosen,i.e.a

productivitythattheteamsarecertaintoachieve.Ifdataarenot

availableorupdatesareneeded,itisrecommendedthatsystematic

recordsoftheteams’dailyproductivityarekeptfromthe

begin-ningofthecampaign.Theserecordscanbecontrastedwiththe

productivityvaluesusedtocalibratethetooltocorrectthefinal

costestimates.

Awiderangeofsituationsexistsinothercountries,thuspossibly

influencingthevaluesofthosetwoparameters(teamproductivity

andpercentagereductioninproductivityforsmallflocks).

There-fore,theflexibilityofVacciCosttoconsiderdifferentproduction

systems withdifferentvaccinationproductivityis animportant

feature.

TheresultsobtainedduringtheVACNADAprojectshowedthat

PPRvaccinationcampaignsin northernSenegalcanbe

success-ful(vaccinationcoverage>80%)whensufficientfinancialresources

areavailable,eventhoughvaccinationcoveragelevelsusedtobe

historicallylowinthisregion(<35%).Thisisanevidencethatthe

capacitiesofSenegaleseVeterinaryServicesarewelldevelopedand

thatthemainconstraintforreachinghighlevelsofimmunizationis

thelackofresources.Giventhesuccessofthisproject,theamount

ofresourcesdedicatedtosocialmobilizationinthisanalysiswas

proportionaltotheinvestmentobservedintheVACNADAproject

(USD425perteam).InSenegal,theseresourceswereusedto

pro-duceanddistributet-shirts,postersandleaflets,andtopayfora

communicationteaminchargeofpromotingthecampaignbefore

thearrivalofthevaccinationteam.Thiseffortmayhavecontributed

tothesignificantincreaseinthevaccinationcoverageexperienced

thatyear.

Atrainingsession(8hofeffectivetraining)wasconsideredfor

allagentsinvolvedinthevaccinationcampaign.Itwouldbe

use-fultostudytheeffectofvaryingtheamountoftrainingonteams’

productivityandoptimizetheresourcesinvestedintraining.The

shareoftotalcostsrepresentedbytrainingwassmallinall

sce-narios(∼1%).Therefore,increasingtrainingmaybeacost-effective

strategyaslongasitresultsinasatisfactoryincreasedlevelof

vac-cinationproductivity.Thecostof increasingtheduration ofthe

trainingshouldalsobetakenintoconsiderationinthedesignof

thetrainingprogram,afterconsultationwithexpertsintraining

engineering,communication,veterinarypublichealth,etc.Ifsuch

expertiseisnotavailableinthecountry,externalexpertise

(supra-nationalanimal health networksorinternationalorganizations)

shouldbeconsidered.

Twoexogenousfactorspusheddowntheresourcerequirements

inthisanalysis.

-Firstly,pricesandwagescollectedwereallinCFAFrancs(XOF).

Sincetheexchangerateusedforthewholeanalysisistheone

observedattheendof2015(i.e.1XOF=0.001655USD),the

depre-ciationexperiencedbytheXOFagainsttheUSD(14%in2014and

11%in2015)madecostsexpressedin2015USD26%lowerthan

iftheyhadbeenestimatedin2013.

-Secondly,transportationcostswereimpactedbyfuelprices.In

June2014,thebarrelofWTIcrudeoilwas>USD100,whereasat

theendof2015,itwas<USD40.Thismarkeddropinoilprice

Table3

ScenariosandresultsobtainedusingVacciCost(costsinUSD).

Scenarios

A B C D

Productivity(PERTdistribution)

Best-case 1500 1500 795 795

Mostlikely 1000 1000 316 316

Worst-case 800 800 100 100

Percentagereductioninproductivityformixedsystems 50% 70% 50% 70%

Averageteams’productivitya _{981 943 343 331}

Totaloperationalcostofthevaccinationcampaign(USD)

95%CI− 1,448,659 1,457,361 1,858,915 1,858,915

Average 1,546,025 1,563,944 2,620,207 2,671,714

95%CI+ 1,663,051 1,663,051 4,113,799 4,236,796

Totaloperationalcostpervaccinatedanimal(USD)

95%CI− 0.18 0.18 0.24 0.24

Average 0.20 0.20 0.33 0.34

95%CI+ 0.21 0.21 0.52 0.54

a_{Theaverageteams’productivityismeasuredbytheaveragenumberofanimalsvaccinatedperteamperday.}

Fig.1.Distributionofcostsbycategoryaccordingtothevaccinationteamproductivityscenario.

wouldbearound25%higherifthepricesofreferencehadbeen

thoseobservedin2013.

Moreover,thevehiclemaintenance cost is estimatedat 15%

ofthefuelcost.Thisestimatecapturesthefactthat thecostof

maintainingavehicleincreaseswithitsutilization.However,the

percentageofthefuelcostthatisusedtoestimatethecostof

main-tenancedepends onthelaborcostsofeachcountry,whichmay

differsignificantly.

Insomecases,farmersareaskedtocoverpartofthevaccination

costs,hencedecreasingtheoverallcost ofthevaccination

cam-paignforthegovernment.Thetotalamounttobesubtractedfrom

thevaccinationcostobtainedwiththeVacciCosttoolcanbeeasily

estimatedbymultiplyingthenumberofvaccinesdeliveredbythe

paymentduebythefarmerforeachvaccine.Thisstrategyis

fre-quentlyadoptedtomakevaccinationcampaignssustainableinthe

longterm.

Thereisalackofconsistentrecordsregardingtransportation

costs,productivity, and distances traveled to reachvaccination

placesfrompreviousvaccination campaigns.Better recordsare

neededtoimprovedataqualitythatwouldcontributetoimprove

theconfidenceinthevaccinationcostestimates.Theimportant

involvementofprivateveterinariansmakesthisestimationmore

complicatedsincetheywouldalsohavetoadoptgoodpracticesto

keeprecordsofthekeyvariablesmentionedabove,andthosedata

shouldbesharedaswell.Sincevaccinationactivitiesaredelegated

theDVScouldbeestablishedasarequirementforthepaymentof

thevaccinationcampaignbythegovernment.

Additionally,thesurveillancecomponentofthistoolprovides

aroughestimateofthesurveillancecosts(serologicaltestsand

wagespaidtothesurveillanceteamtocollectthesamples).

How-ever, since thetool doesnot incorporate anysampling design,

othercomponentsrelevanttosurveillancearenotcaptured.

There-fore,usersofVacciCostshouldbecarefulwhen consideringthe

surveillancecosts,whichrepresentsalowerbound(i.e.thetrue

surveillancecostsareexpectedtobeequalorhigherthanthose

providedbyVacciCost).Furthereffortstodevelopatooldedicated

fortheassessmentofsurveillancecostswouldbeuseful.Ifa

sep-arateanalysisofthesurveillancecostswereavailable,itsresults

couldbeusedincombinationwithVacciCostresultstoaccountfor

surveillanceexpenses.

Whilesufficientfinancialresourcesarerequiredtoimplement

highcoveragevaccinationcampaigns,otherfactorsmayprevent

authoritiesfromreachingtheirobjectives.Forexample,the

capac-ityofthelaboratoryproducing thevaccinemust becheckedto

ensuresufficientandtimelyvaccineprovision.Shortagesof

vac-cinesarefrequentindevelopingcountriesduetolackofequipment

orstaff;itisoneofthemainobstaclestoreachhigh

immuniza-tioncoverages.Therefore,involvingthelaboratorystaffinstrategic

planningmeetingsneedstobeconsidered.

VacciCost’sflexibilitytoconsiderdifferentproductionsystems

isoneofthemainattributesofthetool.However,VacciCostwas

designedtoestimatetheresourcerequirementslinkedtolivestock

vaccinationcampaigns,soitisnotsuitableforwildlifeorpets.

Dif-ferentmodelsshouldbeconceptualizedtoadaptthetooltothe

vaccinationofnon-livestockanimals.

5. Conclusion

VacciCostwasusedtoestimatetheresourcerequirementsof

implementingan80%coveragevaccinationcampaignagainstPPR

inSenegal.Resultsshowthattheproductivityofvaccinationteams

is a crucial parameter: increasing theproductivity can lead to

significantsavings.InthecaseofSenegal,thepercentage

reduc-tion in productivity linked to vaccinating animals managed in

mixedcrop-livestocksystemsincomparisontopastoralsystems

haslittleimpactontheresultsduetothesmallshareofsmall

rumi-nantsraisedundermixedcrop-livestocksystemsinthecountry

(15%).Giventheimportanceoftheteams’productivity,VacciCost

isdesignedtoincludetheuncertaintyaroundthisparameter.

Goodrecordsoflivestockimmunizationcampaignswouldmuch

contributetothe improvementof theaccuracy of theresource

requirementsestimatesdeliveredbyVacciCost.Availabilityofdata

onthevariability ofteams’productivitybetweenthebeginning

(whenanimalsareeasytoreach)andtheend(whenanimalsare

hardtoreach)ofthevaccinationcampaignwouldenrichthis

anal-ysis.

OptimizingtheuseofresourcesiscrucialfortheSenegaleseDVS,

whichfacesseverefinancialconstraints.VacciCostprovidesthem

witha systematic approach to estimatetheresources required

toimplement theirimmunizationstrategy. Intheframeworkof

PPReradication,VacciCostisusefultopreparenationalbudgets

thatfacilitatethedemandforcomplementaryfundingtoreachthe

immunizationcoveragerequiredtoachieveeradication.

Acknowledgments

ThisworkwassupportedbytheEuropeanproject,

FP7-REGPOT-2012-2013-1, “EPIGENESIS”, One Health approach to integrate

Guadelouperesearchonvector-borneandemergingdiseasesinthe

ERA:fromthecharacterizationofemergencemechanismsto

inno-vativeapproachesforpredictionandcontrol(post-doctoralgrantto

D.Tago).WethanktheSenegaleseDirectionofVeterinaryServices

oftheMinistryofLivestockandAnimalProductionfortheprovision

ofdata,andthemembersoftheCaribbeanAnimalHealthNetwork

(CaribVET)fortheirinputonthedevelopmentofthetool.

AppendixA. Supplementarydata

Supplementarydataassociatedwiththisarticlecanbefound,in

theonlineversion,athttp://dx.doi.org/10.1016/j.prevetmed.2017.

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