经济学人2016年3月26日A-jab-in-time

VaccinationAjabintimeSomeWesterncountrieshavelowervaccinationratesthanpoorpartsofAfrica.Anti-vaxxersarenotthemainculpritsMar26th2016|FromtheprinteditionERADICATINGadiseaseisthesortofaimthatrichcountriescomeupwith,andpooronesstruggletoreach.Butforsomediseases,thepatternisreversed.Thesearetheailmentsforwhichvaccinationsexist.Manypoorcountriesrunhighlyeffectivevaccinationprogrammes.Butasmemoriesofthetollfrominfectiousdiseasesfadesacrosstherichworld,insomeplacestheyaremakingacomeback.TheWorldHealthOrganisation(WHO)reckonsthatvaccinessave2.5mlivesayear.Smallpoxwaseradicatedin1980withthehelpofavaccine;polioshouldsoonfollow.Inbothcases,richcountriesledtheway.Thenewpatternlooksverydifferent.Thetrendismostevidentformeasles,whichishighlycontagious.Atleast95%ofpeoplemustbevaccinatedtostopitsspread(athresholdknownas“herdimmunity”).Althoughusuallymild,itcanleadtopneumoniaandcausebraindamageorblindness.Thecountrieswiththelowestvaccinationratesareallverypoor,butmanydevelopingcountriesrunexcellentprogrammes(seechart).Eritrea,RwandaandSriLankamanagetovaccinatenearlyeveryone.Bycontrastseveralrichcountries,includingAmerica,Britain,FranceandItaly,arebelowherdimmunity.LastyearEuropemissedthedeadlineithadsetitselfin2010toeradicatemeasles,andhadalmost4,000cases.Americawasdeclaredmeasles-freein2000;in2014ithadhundredsofcasesacross27statesandlastyearsawitsfirstdeathfromthediseaseinmorethanadecade.Thetrendsforothervaccine-preventablediseases,suchasrubella,whichcancausecongenitaldisabilitiesifapregnantwomancatchesit,arealarming,too.Thissorrystateofaffairsisoftenblamedonhardline“anti-vaxxers”,parentswhorefuseallvaccinesfortheirchildren.Theyareamotleylot.TheAmishinAmericaspurnmodernmedicine,alongwithalmosteverythingelseinventedsincethe17thcentury.Somevegansobjecttotheuseofanimal-derivedproductsinvaccines’manufacture.TheProtestantDutchReformedChurchthinksvaccinesthwartdivinewill.Anthroposophy,foundedinthe19thcenturybyRudolfSteiner,anAustrianmystic-cum-philosopher,preachesthatdiseasesstrengthenchildren’sphysicalandmentaldevelopment.INTERACTIVE:Explorevaccinationcoverageandmeaslescasesworldwidefrom1980to2014Inmostcountriessuchrefuseniksareonly2-3%ofparents.Butbecausetheytendtoliveinclusters,theycanbethesourceofoutbreaks.Abiggerproblem,though,isthegrowingnumberofparentswhodelayvaccination,orpickandchoosejabs.StudiesfromAmerica,AustraliaandEuropesuggestthataboutaquarterofparentsfallintothisgroup,generallybecausetheythinkthatthestandardvaccinationschedule,whichprotectsagainstaroundadozendiseases,“overloads”children’simmunesystems,orthatparticularvaccinesareunsafe.Somebelievevaccinesinterferewith“naturalimmunity”.Manywereshakenbyaclaim,laterdebunked,thattherewasalinkbetweenautismandtheMMRvaccine,whichprotectsagainstmeasles,mumpsandrubella.InAmerica,somepoorchildrenmissoutonvaccinesdespiteafederalprogrammetoprovidethejabsfree,sincetheyhavenoregularrelationshipwithafamilydoctor.SomeoutbreaksineasternEuropehavestartedincommunitiesofRoma(gypsies).Membersofthispoorandostracisedminorityareshunnedbyhealthworkersandoftengounvaccinated.Severalgovernmentsaretryingtoraisevaccinationratesbymakinglifeharderforparentswhodonotvaccinatetheirchildren.AmeaslesoutbreaklastyearthatstartedwithanunvaccinatedchildvisitingDisneylandandspreadfromtheretosevenstatespromptedCaliforniatomakeafullvaccinationrecordaconditionofentrytostateschools.Thepreviousyear,inaquarterofschoolstoofewchildrenhadbeenvaccinatedagainstmeaslestoconferherdimmunity.Adozenotherstatesareconsideringsimilarbills.Afteratoddlerdiedfrommeasleslastyear,Germanyrecentlystartedtoobligeparentswhodonotwishtheirchildrentobevaccinatedtodiscussthedecisionwithadoctorbeforetheycanenrollachildinnursery.Australia’snew“nojabs,nopay”lawwithdrawschildbenefitsfromparentswhodonotvaccinate,unlesstheyhavesoundmedicalreasons.Persuasion,afineartThereis,however,surprisinglylittleevidencethattoughlawsmakeabigdifferencetovaccinationrates.Europeancountriesthataresimilarinmostrespects(suchastheNordics)mayhavesimilarratesforjabsthataremandatoryinonecountrybutnotinanother—orverydifferentratesdespitehavingthesamerules.RatesinsomeAmericanstateswhereparentscaneasilyoptoutareashighasinWestVirginiaandMississippi,whichhavelongallowedonlymedicalexemptions.Andstrictrulesmayevenhardenanti-vaccinationattitudes.Australiahadpreviouslymadeexemptionconditionalonspeakingtoadoctorornurseaboutthebenefitsofvaccines.Thenewrulesmeanfewerchancestochangeparents’minds.Researchsuggeststhatmakingithardertoavoidthemostimportantvaccinesmaymakeitmorelikelythatpeoplewhostronglyopposevaccinationingeneralshunoptionalones,saysCorneliaBetschoftheUniversityofErfurt.Moreimportant,saypublic-healthexperts,istoboostconfidenceinthesafetyofvaccinesandtrustintheauthoritiesthatrecommendthem—bothbadlydamagedinmanyEuropeancountriesbypastpublic-healthmis-steps,suchasascandalwithcontaminatedbloodsupplyinFrancefromthelate1990s.Thebestwaytohandleavaccinescareistoexpressempathyandpromptlysharetheresultsfrominvestigationsofallegedadversereactions,saysHeidiLarsonoftheLondonSchoo