U.S. pharmaceutical giant Pfizer Inc. is in talks with Japan to apply for approval to administer its COVID-19 vaccine to children aged 5 to 11, sources close to the matter said Wednesday.

The revelation came a day after a U.S. Food and Drug Administration panel of independent experts voted in favor of issuing emergency use authorization for the vaccine to be administered to children in that age group.

Photo shows vials of Pfizer Inc.'s COVID-19 vaccine at a hospital in Iwamizawa, Hokkaido, northern Japan, on Feb. 19, 2021. (Kyodo) ==Kyodo

If submitted, Japan's Ministry of Health, Labor and Welfare plans to promptly review the application, according to the sources.

Pfizer's COVID-19 vaccine, jointly developed with German partner BioNTech SE, is currently available free of charge to people aged 12 and older in Japan, where it has been approved for use.

Coverage has not been extended to children below 12 due to uncertainty over the vaccine's efficacy and safety for that group.

In clinical trials conducted by Pfizer in the United States and other countries, administration of a third adult dose of the vaccine was found to be 90.7 percent effective in preventing COVID-19 infections in children between 5 and 11 years, according to data submitted to the FDA.

Although the subjects experienced sore arms, fatigue and headaches the next day, the side effects disappeared quickly and there were no safety issues.

The results led the FDA panel to conclude at a meeting Tuesday that the benefits of the vaccine outweighed the risks even among children.

According to U.S. media, COVID-19 vaccination of kids could start as early as next week, but some remain unconvinced of the necessity due to the low risk of children developing serious symptoms.

Some experts have suggested that the vaccine rollout should only target children with underlying conditions.

Pfizer is expected to apply for approval in Japan using the results of the same clinical trials.