By LAU­RAN NEER­GAARD-As­so­ci­at­ed Press 

Three dos­es of Pfiz­er’s COVID-19 vac­cine of­fer strong pro­tec­tion for chil­dren younger than 5, the com­pa­ny an­nounced Mon­day, an­oth­er step to­ward shots for the lit­tlest kids pos­si­bly be­gin­ning in ear­ly sum­mer. 

Pfiz­er plans to sub­mit the find­ings to U.S. reg­u­la­tors lat­er this week. The Food and Drug Ad­min­is­tra­tion al­ready is eval­u­at­ing an ap­pli­ca­tion by ri­val Mod­er­na to of­fer two-dose vac­ci­na­tions to tots — and set June 15 as a ten­ta­tive date for its in­de­pen­dent sci­en­tif­ic ad­vis­ers to pub­licly de­bate the da­ta from one or both com­pa­nies. 

The news comes af­ter months of anx­ious wait­ing by par­ents des­per­ate to vac­ci­nate their ba­bies, tod­dlers and preschool­ers, es­pe­cial­ly as COVID-19 cas­es once again are ris­ing. The 18 mil­lion young­sters un­der 5 are the on­ly group in the U.S. not yet el­i­gi­ble for COVID-19 vac­ci­na­tion. 

Pfiz­er has had a bumpy time fig­ur­ing out its ap­proach. It aims to give tots an ex­tra low dose — just one-tenth of the amount adults re­ceive — but dis­cov­ered dur­ing its tri­al that two shots didn’t seem quite strong enough for preschool­ers. So re­searchers gave a third shot to more than 1,600 young­sters — from age 6 months to 4 years — dur­ing the win­ter surge of the omi­cron vari­ant. 

In a press re­lease, Pfiz­er and its part­ner BioN­Tech said the ex­tra shot did the trick, revving up the chil­dren’s lev­els of virus-fight­ing an­ti­bod­ies enough to meet FDA cri­te­ria for emer­gency use of the vac­cine with no safe­ty prob­lems. 

Pre­lim­i­nary da­ta sug­gest­ed the three-dose se­ries is 80% ef­fec­tive in pre­vent­ing symp­to­matic COVID-19, the com­pa­nies said, but they cau­tioned the cal­cu­la­tion is based on just 10 cas­es di­ag­nosed among study par­tic­i­pants by the end of April. The study rules state that at least 21 cas­es are need­ed to for­mal­ly de­ter­mine ef­fec­tive­ness, and Pfiz­er promised an up­date as soon as more da­ta is avail­able. 

While the vac­cine ef­fec­tive­ness like­ly could change some­what, “all of this is very pos­i­tive for those par­ents who are look­ing for­ward to hav­ing a vac­cine for their younger chil­dren in the com­ing months,” said Dr. William Moss of the Johns Hop­kins Bloomberg School of Pub­lic Health, who was not part of the study. 

If FDA con­firms the da­ta, the vac­cine could “be an im­por­tant tool to help par­ents pro­tect their chil­dren,” agreed Dr. Jesse Good­man of George­town Uni­ver­si­ty, a for­mer FDA vac­cine chief. But he cau­tioned that it’s es­sen­tial to track how long pro­tec­tion lasts, es­pe­cial­ly against se­ri­ous dis­ease. 

What’s next? FDA vac­cine chief Dr. Pe­ter Marks has pledged the agency will “move quick­ly with­out sac­ri­fic­ing our stan­dards” in eval­u­at­ing tot-sized dos­es from both Pfiz­er and Mod­er­na. 

Com­par­ing the two com­pa­nies’ ap­proach­es to vac­ci­nat­ing the lit­tlest kids promis­es to be chal­leng­ing. 

Mod­er­na asked FDA to au­tho­rize two shots, each con­tain­ing a quar­ter of the dose giv­en to adults. While that spurred good lev­els of virus-fight­ing an­ti­bod­ies, Mod­er­na’s study found ef­fec­tive­ness against symp­to­matic COVID-19 was just 40% to 50% dur­ing the omi­cron surge, much like for adults who’ve on­ly had two vac­cine dos­es. 

“We’ve learned in old­er chil­dren and adults that ... we re­al­ly need three dos­es to get pro­tec­tion” against new­er vari­ants like omi­cron, Moss said. 

That’s some­thing Mod­er­na plans to study, and Moss said he didn’t ex­pect the ques­tion would hold up FDA au­tho­riza­tion of the first two dos­es. 

Com­pli­cat­ing Mod­er­na’s progress, the FDA so far has al­lowed its vac­cine to be used on­ly in adults. Oth­er coun­tries al­low it to be giv­en as young as age 6, and the com­pa­ny al­so is seek­ing FDA au­tho­riza­tion for teens and el­e­men­tary-age kids. 

The FDA has ten­ta­tive­ly planned for its ex­pert pan­el to con­sid­er Mod­er­na’s vac­cine for old­er kids a day be­fore tak­ing up the ques­tion of shots for the lit­tlest. 

If FDA clears ei­ther vac­cine or both, the Cen­ters for Dis­ease Con­trol and Pre­ven­tion would have to rec­om­mend whether all kids un­der 5 should re­ceive the shots or on­ly those at high risk. 

While COVID-19 gen­er­al­ly isn’t as dan­ger­ous to young­sters as to adults, some chil­dren do be­come se­vere­ly ill or even die. And the omi­cron vari­ant hit chil­dren es­pe­cial­ly hard, with those un­der 5 hos­pi­tal­ized at high­er rates than at the peak of the pre­vi­ous delta surge. 

It’s not clear how much de­mand there will be to vac­ci­nate the youngest kids. Pfiz­er shots for 5- to 11-year-olds opened in No­vem­ber, but on­ly about 30% of that age group have got­ten the rec­om­mend­ed ini­tial two dos­es. Last week, U.S. health au­thor­i­ties said el­e­men­tary-age chil­dren should get a boost­er shot just like every­one 12 and old­er is sup­posed to get, for the best pro­tec­tion against the lat­est coro­n­avirus vari­ants.