Japan's health ministry is weighing mixing and matching different COVID-19 vaccines to help ease supply concerns and accelerate the country's inoculation program, the minister in charge of vaccinations said Sunday.

Japan has mostly used COVID-19 vaccines developed by Pfizer Inc. or Moderna Inc. for its inoculation program. AstraZeneca Plc's vaccine, manufactured in Japan under license, was approved in July for use in people aged 40 or older.

Mass inoculation with the AstraZeneca vaccine against COVID-19 begins in Osaka on Aug. 23, 2021. (Pool photo) (Kyodo) ==Kyodo

"We can expect an acceleration in vaccinations if we gain approval" for the mixed-dose approach from the Ministry of Health, Labor and Welfare, Taro Kono said in a television program.

As of Thursday, 43.5 percent of the country's population had received two doses.

As for the administration of a third vaccine shot already under consideration in response to reduced efficacy and breakthrough infection cases among fully vaccinated people, Kono said this can be started for health care workers in October at the earliest and for people aged 65 or older in January or February once authorized.

"We have already secured the necessary quantities" for a booster shot rollout, Kono said.