What is the difference between efficacy and effectiveness?

Effectiveness meanwhile refers to how well it performs in the real world. Although a vaccine that has high efficacy – such as Moderna's ... Skiptomaincontent Home #Vaccineswork Whatisthedifferencebetweenefficacyandeffectiveness? Backto Whatisthedifferencebetweenefficacyandeffectiveness? Thetwotermsusedtodescribehowwelladrugorvaccineworksareoftenusedinterchangeably,buttheyarenotactuallythesamething–here’swhy. 18November2020 Backto Whatisthedifferencebetweenefficacyandeffectiveness? Thetwotermsusedtodescribehowwelladrugorvaccineworksareoftenusedinterchangeably,buttheyarenotactuallythesamething–here’swhy. 18November2020   Efficacyisthedegreetowhichavaccinepreventsdisease,andpossiblyalsotransmission,underidealandcontrolledcircumstances–comparingavaccinatedgroupwithaplacebogroup.Effectivenessmeanwhilereferstohowwellitperformsintherealworld.Althoughavaccinethathashighefficacy–suchasModerna’sCOVID-19vaccinewith94.5%efficacyandPfizer’swith90%efficacy–wouldbeexpectedtobehighlyeffectiveintherealworld,itisunlikelytotranslateintothesameeffectivenessinpractice. Whatisefficacy? Avaccinewithanefficacyof90%inatrial,forinstance,meanstherewasa90%reductionincasesofdiseaseinthevaccinatedgroupcomparedtotheunvaccinated(orplacebo)group.Butefficacyinlaboratoryconditionsdoesnotalwaystranslatetoeffectiveness,andsoanefficacytrialcanoverestimateavaccine’simpactinpractice. Inclinicaltrials,theconditionsunderwhichaparticipantistakingavaccinearecarefullydesigned–peopleareoftennotincludedintrialsiftheyhaveunderlyinghealthissues,oraretakingmedication–andsideeffectsarecloselymonitored. Moreover,participantsinthetrialrepresentasubsectionofthefullagerangeofapopulation.Forexample,notmanyCOVID-19vaccinetrialshaveincludedyoungchildren,eventhoughtheymayalsoneedtoreceivethevaccinewhenoneisready. Howdowemeasureeffectiveness? Whenavaccineisgiventothepopulation,factors,suchasthemedicationpeoplearetaking,underlyingchronicillnesses,age,andhowthevaccineisstoredandadministeredundereverydayconditions,canreducehoweffectivethevaccineisatpreventingdisease. Oncetheefficacyofavaccinehasbeendetermined,measuringitseffectivenessiscriticaltoensuringuptakeofthevaccineandtounderstandhowtodevelopbettervaccines.Surveillancedataisvitaltounderstandingeffectiveness,asisimmunisationdata–capturingdata,forexample,onwhenpeoplegetthevaccineandwhatproportionofthepopulationinagivencountryiscovered. Effectivenessofavaccineismeasuredinwhatepidemiologistscallobservationalstudiesbecauseparticipantsarenotrandomlyassignedtoatreatmentversusaplacebogroup. Forexample,case-controlstudiesassesseffectivenessbycomparingthevaccinationstatusofindividualswhodevelopthedisease(cases)withagroupofindividualswithoutthedisease(controls)whoarealsorepresentativeofthepopulationfromwhichthecasesarise.Ifthevaccineiseffective,thecasesaremorelikelytobetheunvaccinatedindividuals. Vaccinesdonotalwaysneedtohaveanexceptionallyhigheffectivenesstobeuseful,forexampletheinfluenzavaccineis40-60%effectiveyetsavesthousandsofliveseveryyear. TOPICS:COVID-19 RelatedContent TacklingCOVIDdisinformationwithempathyand conversation COVID-19 10December2021 ThePandemicandAfrica'sSocialSafetyNet CountrystoriesCOVID-19 10December2021 COVID-19vaccinesandpregnancy–here’swhatyouneedtoknow COVID-19Gender 10December2021 We'vehadCOVID-19vaccinesforoneyear.Howcanwemakebetteruseofthem? COVID-19COVAX 9December2021 Howamix-and-matchvaccineapproachcouldboostimmunitytoCOVID-19 COVID-19Educational 9December2021 AnodetohealthworkersonthehighwaysofMonterrey,Mexico PandemicCultureCOVID-19 9December2021 Viewmore Subscribetoournewsletter Subscribe FirstName LastName Email Company Country Leavethisfieldblank