Malaria vac­cine is a let­down but could still re­duce num­bers of cases

The China Post - - INTERNATIONAL - BY MARIA CHENG

The world’s lead­ing malaria vac­cine can­di­date ap­pears to be a dis­ap­point­ment, with fi­nal study re­sults show­ing it doesn’t work very well and that ini­tial pro­tec­tion fades over time.

De­spite the dis­mal re­sults — it protects about one-third of chil­dren vac­ci­nated — de­vel­op­ers are mov­ing ahead to get it ap­proved be­cause it could still help pro­tect some chil­dren from get­ting the mos­quito-spread dis­ease.

Glax­oSmithK­line has spent hun­dreds of mil­lions of dol­lars on the vac­cine, which is likely to be the world’s first li­censed shot for malaria. A de­ci­sion from the Euro­pean Medicines Agency is ex­pected later this year.

The World Health Or­ga­ni­za­tion had pre­vi­ously set a tar­get of 2015 for hav­ing a malaria vac­cine that was at least 50 per­cent ef­fec­tive with pro­tec­tion last­ing longer than a year. Ac­cord­ing to a study pub­lished Fri­day in the jour­nal The Lancet, those goals have been missed with the Glax­oSmithK­line vac­cine, though sci­en­tists say the shot isn’t a com­plete waste.

“Ev­ery­one ac­cepts that this is not the per­fect or the last malaria vac­cine,” said Brian Green­wood of the Lon­don School of Hy­giene and Trop­i­cal Medicine, the study’s lead au­thor. “It’s not good enough to stop trans­mis­sion but it will cut the huge bur­den of dis­ease.”

He noted there are about 200 mil­lion cases of malaria ev­ery year, with many chil­dren in­fected mul­ti­ple times.

“Pre­vent­ing some of those at­tacks is not in­signif­i­cant,” he said. The vac­cine study in­volved about 15,500 ba­bies and tod­dlers in Africa; one group got three doses; a sec­ond group also got a booster shot and a third group got dummy shots. All of the chil­dren used a mos­quito bed net and they were fol­lowed for up to four years.

Over­all, the vac­cine was about 30 per­cent ef­fec­tive in those who got three doses and a booster shot but the pro­tec­tion waned over time.

It worked a lit­tle bet­ter — about 36 per­cent — in those 5 months to 17 months. But it was only 26 per­cent ef­fec­tive in ba­bies and vac- cina­tion made no dif­fer­ence in the rates of se­vere malaria or deaths.

More com­monly used vac­cines, like those for measles and po­lio, work more than 90 per­cent of the time.

Re­searchers re­ported side ef­fects in­clud­ing pain, fever and con­vul­sions. There were also 22 cases of menin­gi­tis in ba­bies and tod­dlers who were im­mu­nized com­pared to one case in the group that didn’t, but the re­searchers couldn’t ex­plain why.

Green­wood said the vac­cine would likely be made avail­able at cost and that ma­jor fun­ders have al­ready ex­pressed in­ter­est in pay­ing for im­mu­niza­tion cam­paigns. Other ex­per­i­men­tal malaria vac­cines are be­ing de­vel­oped but are at least sev­eral years be­hind.

WHO es­ti­mates malaria killed more than 580,000 peo­ple in 2013, mostly chil­dren in Africa un­der age 5. Of­fi­cials mostly try to slow the mos­quito-spread dis­ease us­ing bed nets, in­sec­ti­cide spray­ing, and giv­ing out malaria med­i­ca­tions to en­tire vil­lages in ar­eas with high lev­els of the dis­ease.

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