Japan is planning to approve the COVID-19 vaccine developed by Britain's AstraZeneca Plc for inoculations of those aged 60 and over, government sources said Tuesday.

The Ministry of Health, Labor and Welfare granted fast-track approval for the vaccine in May, but indicated at the time it did not intend to use the vaccine immediately due to rare cases of blood clots reported overseas.

Photo shows bottles of COVID-19 vaccine developed by AstraZeneca Plc and the University of Oxford. (Photo courtesy of AstraZeneca)(Kyodo)

But some health experts have said the vaccine should "not be excluded as an option" as its efficacy has been confirmed in Britain and other countries where a significant number of shots have been administered.

A health ministry panel will discuss the eligible age range for the vaccine at a meeting on June 30, while taking into account the situation overseas, the sources said.

Unlike the COVID-19 vaccines developed by U.S. pharmaceutical companies Pfizer Inc. and Moderna Inc., both of which use a new technology called messenger RNA, the AstraZeneca vaccine uses a harmless version of a common cold virus.

The AstraZeneca vaccine has proved 70 percent effective against the virus, slightly lower than the other two. But it has the advantage of being easier to store and is produced under license in Japan.