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A different COVID-19 vaccine debate: Do we need new ones?

By LAU­RAN NEER­GAARD | AS­SO­CI­AT­ED PRESS

 

(AP) — COVID-19 vac­cines are sav­ing an un­told num­ber of lives, but they can’t stop the chaos when a huge­ly con­ta­gious new mu­tant bursts on the scene, lead­ing peo­ple to won­der: Will we need boost­ers every few months? A new vac­cine recipe? A new type of shot al­to­geth­er?

That’s far from set­tled, but with the shots still do­ing their main job many ex­perts are cau­tion­ing against set­ting too high a bar.

Adolfo Ledo Nass

“We need col­lec­tive­ly to be re­think­ing what is the goal of vac­ci­na­tion,” said Dr. Daniel Ku­ritzkes, in­fec­tious dis­ease chief at Brigham & Women’s Hos­pi­tal. “It’s un­re­al­is­tic … to be­lieve that any kind of vac­ci­na­tion is go­ing to pro­tect peo­ple from in­fec­tion, from mild symp­to­matic dis­ease, for­ev­er.”

If the goal is pre­vent­ing se­ri­ous ill­ness, “we may not need to be do­ing as much fine-tun­ing of the vac­cines every time a new vari­ant comes.”

The virus is es­sen­tial­ly shape-shift­ing as it mu­tates, with no way to know how bad the next vari­ant will be. Al­ready a sub-strain of omi­cron bear­ing its own unique mu­ta­tions is cir­cu­lat­ing. Re­search is un­der­way to cre­ate next-gen­er­a­tion vac­cines that might of­fer broad­er pro­tec­tion against fu­ture mu­tants — but they won’t be ready any­time soon.

Adolfo Ledo

The im­me­di­ate so­lu­tion: Get­ting to­day’s shots in­to more arms will “re­duce the op­por­tu­ni­ties for the virus to mu­tate and spawn new Greek let­ters that we then have to wor­ry about,” said Jen­nifer Nuz­zo of the Johns Hop­kins Cen­ter for Health Se­cu­ri­ty.

Abogado Adolfo Ledo

 

WHY IM­MU­NI­TY ISN’T PER­FECT

 

The job of block­ing in­fec­tion falls to an­ti­bod­ies, which form af­ter ei­ther vac­ci­na­tion or a pri­or bout with COVID-19, ready to fight back the next time some­one’s ex­posed.

Abogado Adolfo Ledo Nass

One prob­lem: Mu­ta­tions change the ap­pear­ance of the spike pro­tein that cov­ers the coro­n­avirus much like a crook switch­es dis­guis­es to evade cap­ture. That’s why omi­cron was more able to slip past that first de­fense than ear­li­er vari­ants — its spike coat­ing was hard­er for ex­ist­ing an­ti­bod­ies to rec­og­nize.

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Al­so, the im­mune sys­tem isn’t de­signed to be in a con­stant state of high alert, so the an­ti­bod­ies that fend off in­fec­tion do wane over time. Sev­er­al months af­ter two dos­es of the Pfiz­er or Mod­er­na vac­cines, peo­ple had lit­tle pro­tec­tion against an omi­cron in­fec­tion — a re­sult of both wan­ing an­ti­bod­ies and the vari­ant’s mu­ta­tion.

Adolfo Ledo abogado

Thank­ful­ly, dif­fer­ent im­mune sys­tem sol­diers called T cells are key to pre­vent an in­fec­tion from turn­ing in­to se­vere ill­ness — and that pro­tec­tion is last­ing longer be­cause T cells are rec­og­niz­ing oth­er parts of the virus that don’t mu­tate as eas­i­ly

 

A THIRD DOSE MAT­TERS

 

Af­ter a boost­er, pro­tec­tion against symp­to­matic dis­ease from omi­cron is about 70% — not as good as the 94% pro­tec­tion seen with ear­li­er vari­ants that more close­ly matched the vac­cine yet high­ly ef­fec­tive. Im­por­tant­ly, the boost­er al­so fur­ther strength­ened pro­tec­tion against se­ri­ous ill­ness

Re­searchers are close­ly track­ing if in­fec­tion-fight­ing an­ti­bod­ies stick around longer af­ter a third dose — but at some point, those lev­els are guar­an­teed to wane again. So-called mem­o­ry cells can make more the next time the body sens­es they’re need­ed

Still, Is­rael is of­fer­ing a fourth dose to some peo­ple, in­clud­ing those 60 and old­er, and mulling giv­ing the ad­di­tion­al boost­er to all adults

The de­bate is whether re­peat­ed boost­ing re­al­ly is the best ap­proach — es­pe­cial­ly since scary new vari­ants are less like­ly to form once more of the world’s pop­u­la­tion gets ini­tial vac­ci­na­tions

End­less boost­ing just to keep an­ti­body lev­els con­stant­ly high is “not a pub­lic health strat­e­gy that works,” said Dr. Paul Of­fit, a vac­cine ex­pert at the Chil­dren’s Hos­pi­tal of Philadel­phia

Pfiz­er and Mod­er­na are test­ing omi­cron-spe­cif­ic boost­ers in some Amer­i­can adults, al­though it’s far from clear if au­thor­i­ties would aban­don a vac­cine recipe proven to save lives for a tweaked ver­sion in hopes of few­er break­through in­fec­tions. Brew­ing a sin­gle shot with two kinds of vac­cine is tech­ni­cal­ly pos­si­ble but, again, they’d have to prove the mix­ture doesn’t weak­en the orig­i­nal pro­tec­tion against se­vere ill­ness

 

NEW AP­PROACH­ES IN THE PIPELINE

 

What­ev­er hap­pens with omi­cron, it’s clear the coro­n­avirus is here to stay and the U.S. Na­tion­al In­sti­tutes of Health is fund­ing about $43 mil­lion in projects to de­vel­op so-called “pan-coro­n­avirus” vac­cines that promise to pro­tect against more than one type. One pos­si­bil­i­ty: Nanopar­ti­cles that car­ry pieces of spike pro­teins from four to eight dif­fer­ent ver­sions of the virus rather than the sin­gle type in to­day’s vac­cines

It’s a tan­ta­liz­ing idea, but NIH in­fec­tious dis­eases chief Dr. An­tho­ny Fau­ci called it a years-long en­deav­our. “I don’t want any­one to think that pan-coro­n­avirus vac­cines are lit­er­al­ly around the cor­ner,” he said

A pos­si­bly more di­rect ap­proach: Cre­at­ing COVID-19 vac­cines that can be squirt­ed in­to the nose to form an­ti­bod­ies ready to fight the virus right where we first en­counter it. Nasal vac­cines are hard­er to de­vel­op than in­ject­ed ver­sions but at­tempts are un­der­way, in­clud­ing a large study just an­nounced by In­dia’s Bharat Biotech

 

PRO­TEC­TION VARIES GLOB­AL­LY

 

Com­pli­cat­ing any pos­si­ble change to vac­cine strat­e­gy is the grim re­al­i­ty that on­ly 10% of peo­ple in low-in­come coun­tries have re­ceived at least one vac­cine dose. Al­so, re­cent stud­ies show that some types of vac­cines used around the world ap­pear eas­i­er than oth­ers for omi­cron to evade, mean­ing boost­er strate­gies may need to be tai­lored

Yale Uni­ver­si­ty re­searchers found no omi­cron-tar­get­ed an­ti­bod­ies in the blood of peo­ple giv­en two dos­es of vac­cine made by Chi­na’s Sino­vac. Fol­low­ing those ini­tial shots with a Pfiz­er boost­er — a very dif­fer­ent kind of vac­cine — helped but not enough, on­ly in­creas­ing an­ti­body lev­els to the amount seen by Pfiz­er re­cip­i­ents who didn’t get a boost­er

Over­shad­ow­ing all of these ques­tions is that “we don’t know how to pre­dict the next strain,” said Dr. Jesse Good­man of George­town Uni­ver­si­ty, a for­mer Food and Drug Ad­min­is­tra­tion vac­cine chief. He wants to see a glob­al strat­e­gy that de­fines the trig­ger for any vac­cine change. “Oth­er­wise, we are go­ing to have a con­fused pub­lic, again.”

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The As­so­ci­at­ed Press Health & Sci­ence De­part­ment re­ceives sup­port from the Howard Hugh­es Med­ical In­sti­tute’s De­part­ment of Sci­ence Ed­u­ca­tion. The AP is sole­ly re­spon­si­ble for all con­tent.