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Monday, February 17, 2025

Mix and matching some COVID vaccines gives high immunity: Study

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1168 days ago
20211207
Many countries have been deploying a mix-and-match approach well before robust data was available [File: Kirsty Wigglesworth/AP Photo]

Many countries have been deploying a mix-and-match approach well before robust data was available [File: Kirsty Wigglesworth/AP Photo]

SOURCE: AL JAZEERA

Ox­ford Uni­ver­si­ty study finds mix­ing a first dose of the Pfiz­er or As­trazeneca vac­cine with a sec­ond Mod­er­na shot yields high­er an­ti­bod­ies

(AL JAZEERA) - A ma­jor British study in­to mix­ing COVID-19 vac­cines has found that peo­ple had a bet­ter im­mune re­sponse when they re­ceived a first dose of As­traZeneca or Pfiz­er-BioN­Tech shots fol­lowed by Mod­er­na nine weeks lat­er, ac­cord­ing to the re­sults.

“We found a re­al­ly good im­mune re­sponse across the board … in fact, high­er than the thresh­old set by Ox­ford-As­traZeneca vac­cine two dos­es,” Matthew Snape, the Ox­ford pro­fes­sor be­hind the Com-COV2 tri­al, told the Reuters news agency on Mon­day.

The find­ings sup­port­ing flex­i­ble dos­ing will of­fer some hope to low- and mid­dle-in­come coun­tries that may need to mix vac­cines for first and sec­ond dos­es if sup­plies run low or be­come un­sta­ble.

“I think the da­ta from this study will be es­pe­cial­ly in­ter­est­ing and valu­able to low- and mid­dle-in­come coun­tries where they’re still rolling out the first two dos­es of vac­cines,” Snape said.

“We’re show­ing … you don’t have to stick rigid­ly to re­ceiv­ing the same vac­cine for a sec­ond dose … and that if the pro­gramme will be de­liv­ered more quick­ly by us­ing mul­ti­ple vac­cines, then it is OK to do so.”

If the As­traZeneca-Ox­ford vac­cine is fol­lowed by a Mod­er­na or No­vavax shot, high­er an­ti­bod­ies and T-cell re­spons­es were in­duced ver­sus two dos­es of As­traZeneca-Ox­ford, ac­cord­ing to re­searchers at the Uni­ver­si­ty of Ox­ford.

The study of 1,070 vol­un­teers al­so found that a dose of the Pfiz­er-BioN­Tech vac­cine fol­lowed by a Mod­er­na shot was bet­ter than two dos­es of Pfiz­er-BioN­Tech.

Pfiz­er-BioN­Tech fol­lowed by No­vavax in­duced high­er an­ti­bod­ies than the two-dose Ox­ford-As­traZeneca sched­ule, al­though this sched­ule in­duced low­er an­ti­body and T-cell re­spons­es than the two-dose Pfiz­er-BioN­Tech sched­ule.

No safe­ty con­cerns were raised, ac­cord­ing to the Ox­ford Uni­ver­si­ty study pub­lished in the Lancet med­ical jour­nal.

Many coun­tries have been de­ploy­ing a mix-and-match ap­proach well be­fore ro­bust da­ta was avail­able as they were faced with soar­ing in­fec­tion num­bers, low sup­plies and slow im­mu­ni­sa­tion over some safe­ty con­cerns.

The longevi­ty of pro­tec­tion of­fered by vac­cines has been un­der scruti­ny, with boost­er dos­es be­ing con­sid­ered as well amid surg­ing cas­es. The dis­cov­ery of new vari­ants, in­clud­ing Delta and Omi­cron, has in­creased the pres­sure to speed up vac­ci­na­tion cam­paigns.

Blood sam­ples from par­tic­i­pants were test­ed against the Wild-Type, Be­ta and Delta vari­ants, re­searchers of the Com-COV2 study said, adding that vac­cines’ ef­fi­ca­cy against the vari­ants had waned, but this was con­sis­tent across mixed cours­es.

De­ploy­ing vac­cines us­ing dif­fer­ent tech­nol­o­gy – like Pfiz­er-BioN­Tech and Mod­er­na’s mR­NA, As­traZeneca’s vi­ral vec­tor and No­vavax’s pro­tein-based shot – with­in the same sched­ule is a rel­a­tive­ly new ap­proach.

The re­sults may in­form new ap­proach­es to im­mu­ni­sa­tion against oth­er dis­eases, Snape said.

The study al­so found that a first dose of the As­traZeneca-Ox­ford vac­cine fol­lowed by any of the oth­er can­di­dates in the study gen­er­at­ed a par­tic­u­lar­ly ro­bust re­sponse, con­sis­tent with find­ings in June.

The study was de­signed as a so-called “non-in­fe­ri­or­i­ty” study – the in­tent is to demon­strate that mix­ing is not sub­stan­tial­ly worse than the stan­dard sched­ules – and com­pares the im­mune sys­tem re­spons­es to the gold-stan­dard re­spons­es re­port­ed in pre­vi­ous clin­i­cal tri­als of each vac­cine.

Sep­a­rate­ly on Mon­day, the World Health Or­ga­ni­za­tion ad­vised against us­ing the blood plas­ma of pa­tients who have re­cov­ered from COVID-19 to treat those who are ill, say­ing cur­rent ev­i­dence shows it nei­ther im­proves sur­vival nor re­duces the need for ven­ti­la­tors.

The method is al­so cost­ly and time-con­sum­ing to ad­min­is­ter, the WHO said in a state­ment.

The hy­poth­e­sis for us­ing plas­ma is that the an­ti­bod­ies it con­tains could stop the nov­el coro­n­avirus from repli­cat­ing and halt tis­sue dam­age. Sev­er­al stud­ies test­ing con­va­les­cent blood plas­ma have shown no ap­par­ent ben­e­fit for treat­ing COVID-19 pa­tients who are se­vere­ly ill.

COVID-19Health


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