Pfizer on Monday said its COVID-19 vaccine had boosted antibody levels in children aged 5 to 11. The pharma giant will now seek emergency use authorisation for this age group amid concerns of highly-contagious Delta variant causing a surge in pediatric infections with the reopening of schools. A third of the current dosage of the Pfizer-BioNTech vaccine was tested on 2,268 kindergartners and elementary school-aged kids, with the second dose helping them reach antibody levels just as strong as teenagers and young adults, Dr. Bill Gruber, a Pfizer senior vice president said. The dosage also proved safe, he said.

“I think we really hit the sweet spot,” Gruber, who’s also a pediatrician, said.

Gruber said Pfizer and its German partner BioNTech will apply to the Food and Drug Administration (FDA) by the end of the month for emergency use in this age group. The companies will also seek the approval of European and British regulators shortly afterwards.

Earlier this month, FDA chief Dr Peter Marks has said the Pfizer’s study results will be evaluated “hopefully in a matter of weeks” to decide if the vaccines are safe and effective for younger kids.

The FDA would require an immune “bridging” study as evidence of younger children developing antibody levels already proven to be protective in teens and adults.

US vaccine maker, Moderna, is studying its shots in elementary school-aged children as well.

More than 5 million children in the US have tested positive for coronavirus, while at least 460 have died, according to the American Academy of Pediatrics.

Cuba has become the first country to vaccinate children as young as two years old against coronavirus, but many Western countries are still apprehensive about inoculating children younger than age 12. Children aged 6 and older can get a dose of China’s Sinovac vaccine in Chile, while Sinovac and CoronaVac shots can both be administered on children as young as 3 in China. The UAE is also planning to allow parents to vaccinate children as young as three as part of an optional paediatric vaccination program.

(With inputs from Associated Press)