By VIC­TO­RIA MILKO | AS­SO­CI­AT­ED PRESS

(AP) — Is omi­cron lead­ing us clos­er to herd im­mu­ni­ty against COVID-19? Ex­perts say it’s not like­ly that the high­ly trans­mis­si­ble vari­ant — or any oth­er vari­ant — will lead to herd im­mu­ni­ty.

“Herd im­mu­ni­ty is an elu­sive con­cept and doesn’t ap­ply to coro­n­avirus,” says Dr. Don Mil­ton at the Uni­ver­si­ty of Mary­land School of Pub­lic Health.

Herd im­mu­ni­ty is when enough of a pop­u­la­tion is im­mune to a virus that it’s hard for the germ to spread to those who aren’t pro­tect­ed by vac­ci­na­tion or a pri­or in­fec­tion.

For ex­am­ple, herd im­mu­ni­ty against measles re­quires about 95% of a com­mu­ni­ty to be im­mune. Ear­ly hopes of herd im­mu­ni­ty against the coro­n­avirus fad­ed for sev­er­al rea­sons.

One is that an­ti­bod­ies de­vel­oped from avail­able vac­cines or pre­vi­ous in­fec­tion dwin­dle with time. While vac­cines of­fer strong pro­tec­tion against se­vere ill­ness, wan­ing an­ti­bod­ies mean it’s still pos­si­ble to get in­fect­ed — even for those who are boost­ed.

Then there’s the huge vari­a­tion in vac­ci­na­tions. In some low-in­come coun­tries, less than 5% of the pop­u­la­tion is vac­ci­nat­ed. Rich coun­tries are strug­gling with vac­cine hes­i­tan­cy. And young chil­dren still aren’t el­i­gi­ble in many places.

As long as the virus spreads, it mu­tates — help­ing the virus sur­vive and giv­ing rise to new vari­ants. Those mu­tants — such as omi­cron — can be­come bet­ter at evad­ing the pro­tec­tion peo­ple have from vac­cines or an ear­li­er in­fec­tion.

Pop­u­la­tions are mov­ing to­ward “herd re­sis­tance,” where in­fec­tions will con­tin­ue, but peo­ple have enough pro­tec­tion that fu­ture spikes won’t be as dis­rup­tive to so­ci­ety, Mil­ton says.

Many sci­en­tists be­lieve COVID-19 will even­tu­al­ly be­come like the flu and cause sea­son­al out­breaks but not huge surges.