By LAU­RAN NEER­GAARD-As­so­ci­at­ed Press

Mod­er­na’s COVID-19 vac­cine works in ba­bies, tod­dlers and preschool­ers the com­pa­ny an­nounced Wednes­day -- and if reg­u­la­tors agree it could mean a chance to fi­nal­ly start vac­ci­nat­ing the lit­tlest kids by sum­mer.

Mod­er­na said in the com­ing weeks it would ask reg­u­la­tors in the U.S. and Eu­rope to au­tho­rize two small-dose shots for young­sters un­der 6. The com­pa­ny al­so is seek­ing to have larg­er-dose shots cleared for old­er chil­dren and teens in the U.S.

The na­tion’s 18 mil­lion chil­dren un­der 5 are the on­ly age group not yet el­i­gi­ble for vac­ci­na­tion. Com­peti­tor Pfiz­er cur­rent­ly of­fers kid-sized dos­es for school-age chil­dren and full-strength shots for those 12 and old­er.

But par­ents have anx­ious­ly await­ed pro­tec­tion for younger tots, dis­ap­point­ed by set­backs and con­fu­sion over which shots might work and when. Pfiz­er is test­ing even small­er dos­es for chil­dren un­der 5 but had to add a third shot to its study when two didn’t prove strong enough. Those re­sults are ex­pect­ed by ear­ly April.

Vac­ci­nat­ing the lit­tlest “has been some­what of a mov­ing tar­get over the last cou­ple of months,” Dr. Bill Muller of North­west­ern Uni­ver­si­ty, an in­ves­ti­ga­tor in Mod­er­na’s pe­di­atric stud­ies, said in an in­ter­view be­fore the com­pa­ny re­leased its find­ings. “There’s still, I think, a lin­ger­ing ur­gency to try to get that done as soon as pos­si­ble.”

The younger the child, the small­er the dose be­ing test­ed. Mod­er­na said a quar­ter of the dose it us­es for adults worked well for young­sters un­der age 6.

Mod­er­na en­rolled about 6,900 tots in a study of the 25-mi­cro­gram dos­es. Ear­ly da­ta showed af­ter two shots, young­sters de­vel­oped virus-fight­ing an­ti­body lev­els just as strong as young adults get­ting reg­u­lar-strength shots, the com­pa­ny said in a press re­lease.

Mod­er­na said the small dos­es were safe, and the main side ef­fects were mild fevers like those as­so­ci­at­ed with oth­er com­mon­ly used pe­di­atric vac­cines.

Once Mod­er­na sub­mits the da­ta to the FDA, reg­u­la­tors will de­bate whether to au­tho­rize emer­gency use of the small dos­es for tots. If so, the Cen­ters for Dis­ease Con­trol and Pre­ven­tion then will de­cide whether to rec­om­mend them.

While COVID-19 gen­er­al­ly isn’t as dan­ger­ous to young­sters as to adults, some do be­come se­vere­ly ill. The CDC says about 400 chil­dren younger than 5 have died from COVID-19 since the pan­dem­ic’s start. The omi­cron vari­ant hit chil­dren es­pe­cial­ly hard, with those un­der 5 hos­pi­tal­ized at high­er rates than at the peak of the pre­vi­ous delta surge, the CDC found.

COVID-19 vac­cines in gen­er­al don’t pre­vent in­fec­tion with the omi­cron mu­tant as well as they fend­ed off ear­li­er vari­ants -- but they do still of­fer strong pro­tec­tion against se­vere ill­ness.

Mod­er­na re­port­ed that same trend in the tri­al of chil­dren un­der 6, con­duct­ed dur­ing the omi­cron surge. While there were no se­vere ill­ness­es, the vac­cine proved just un­der 44% ef­fec­tive at pre­vent­ing any in­fec­tion in ba­bies up to age 2, and near­ly 38% ef­fec­tive in the preschool­ers.

Mod­er­na said al­so said Wednes­day it will ask the Food and Drug Ad­min­is­tra­tion to clear larg­er dos­es for old­er chil­dren.

While oth­er coun­tries al­ready have al­lowed Mod­er­na’s shots to be used in chil­dren as young as 6, the U.S. has lim­it­ed its vac­cine to adults. A Mod­er­na re­quest to ex­pand its shots to 12- to 17-year-olds has been stalled for months.

The com­pa­ny said Wednes­day that, armed with ad­di­tion­al ev­i­dence, it is up­dat­ing its FDA ap­pli­ca­tion for teen shots and re­quest­ing a green light for 6- to 11-year-olds, too.

Mod­er­na says its orig­i­nal adult dose -- two 100-mi­cro­gram shots -- is safe and ef­fec­tive in 12- to 17-year-olds. For el­e­men­tary-age kids, it’s us­ing half the adult dose.

But the FDA nev­er ruled on Mod­er­na’s ap­pli­ca­tion for teen shots be­cause of con­cern about a very rare side ef­fect. Heart in­flam­ma­tion some­times oc­curs in teens and young adults, most­ly males, af­ter re­ceiv­ing ei­ther the Pfiz­er or Mod­er­na vac­cines. Mod­er­na is get­ting ex­tra scruti­ny be­cause its shots are a far high­er dose than Pfiz­er’s.

The risk al­so seems linked to pu­ber­ty, and reg­u­la­tors in Cana­da, Eu­rope and else­where re­cent­ly ex­pand­ed Mod­er­na vac­ci­na­tions to kids as young as 6.

“That con­cern has not been seen in the younger chil­dren,” said North­west­ern’s Muller.