A Japanese health ministry panel approved on Friday expanding the use of the U.S. pharmaceutical maker Pfizer Inc.'s COVID-19 vaccine for people aged 12 to 15 in addition to those 16 or older.

The ministry is expected to decide at a meeting Monday to provide the vaccine free for those aged between 12 and 15.

A senior citizen receives the Pfizer coronavirus vaccine at a newly opened vaccination center in Kobe, western Japan, on May 25, 2021. (Kyodo) ==Kyodo

The panel also gave the green light to extending the vaccine's maximum storage period at temperatures between 2 and 8 C to one month from five days. For longer-term storage, the Pfizer vaccine needs to be kept at a temperature of around minus 75 C.

Pfizer has been working with the Pharmaceuticals and Medical Devices Agency in Japan to expand authorization of its vaccines for younger people, as well as to extend the storage period, which have been authorized in other countries.

In the company's clinical trial involving 2,260 children aged between 12 and 15 years, 18 who were given a placebo were later infected with the novel coronavirus, while none administered with the vaccine were confirmed with the virus.

The Japanese government approved the Pfizer vaccine in February and began inoculating health care workers. Vaccinations for the elderly began in April.

Japan is receiving enough Pfizer vaccines for 97 million people.

U.S. company Moderna Inc. has also released clinical study results showing effectiveness of its vaccine in children between the ages of 12 and 17 and is preparing to expand its use for them in some countries. It is currently authorized for people over the age of 18.

Japan approved Moderna's COVID-19 vaccine earlier in the month.