(Bloomberg) -- Pfizer Inc. and BioNTech SE asked US regulators to clear their booster shot that targets fast-spreading variants of omicron for children ages 5 to 11, which would bring the latest preventive technology to a younger population. 

The vaccine partners applied to the Food and Drug Administration for emergency use authorization of a 10-microgram booster dose aimed specifically at the omicron BA.4 and BA.5 strains, according to a statement Monday. An application will be submitted to European regulators in the coming days, they said. 

Adult doses of the booster began rolling out earlier in September, although demand for Covid vaccines has weakened as public concerns about the pandemic have eased. Some FDA advisers who recommended clearing the boosters also said that they would have liked more safety and efficacy data. 

The omicron-targeting vaccine is an update of the original shots that were designed specifically to fight the strain of the coronavirus that first emerged in Wuhan, China. The companies have also started a study to evaluate different dosing regimens of the latest vaccines in children from the ages of 6 months to 11 years, according to the statement.

Pfizer shares fell 0.7% in trading before US markets opened, while BioNTech’s American depositary receipts slipped 1.4% on light trading.

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