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A syringe is prepared with a dose of Pfizer's COVID-19 vaccine at a clinic in Chester, Pa., on Dec. 15, 2021.Matt Rourke/The Associated Press

Pfizer Inc. and partner BioNTech have completed the filing with the U.S. drugs regulator seeking authorization for their COVID-19 vaccine in children under five years old.

The filing with the U.S. Food and Drug Administration (FDA), completed on Wednesday, included data showing three lower-dose shots of the vaccine generated a strong immune response in children as young as six months of age.

No COVID-19 shot is yet approved for children in that age group in most parts of the world. It remains unclear how many parents will get their young ones vaccinated as demand has been low in kids between the ages of five to 11.

Pfizer and BioNTech on May 23 said their trial showed a three-microgram version of the vaccine generated a similar immune response in those under five years old as two doses of 30-micrograms each in 16- to 25-year-olds in an earlier trial.

Rival Moderna in March released trial data that showed a two-dose formulation of its vaccine was safe and generated a similar immune response in young children as in adults.

The FDA’s independent advisers will discuss the two applications in a meeting set for June 15.

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