The Japanese government granted fast-track approval to COVID-19 vaccines developed by Moderna Inc. of the United States and Britain's AstraZeneca Plc on Friday, taking a major step toward speeding up its sluggish inoculation drive.
The health ministry said it confirmed both to be safe and effective, bringing the number of available vaccines in the country to three, including one developed by U.S. pharmaceutical company Pfizer Inc. and its German partner BioNTech SE already in use.
The Moderna vaccine, greenlit for use in people aged 18 or older, is slated to be administered at mass vaccination centers run by the Self-Defense Forces in Tokyo and Osaka, as well as similar facilities being set up by some prefectures and municipalities.
The AstraZeneca shot, however, will not be used immediately amid lingering concerns over rare cases of blood clots being reported overseas, the Ministry of Health, Labor and Welfare said.
Japan's vaccination program is lagging behind other developed countries. Since its launch in February, beginning with health care workers and later expanding to people aged 65 or older, only around 4 percent of the country's population of 126 million has received at least one dose.
Prime Minister Yoshihide Suga, whose public support has fallen amid criticism over his pandemic response, has vowed to ramp up to 1 million shots a day and finish inoculating the elderly by the end of July.
A government survey released Friday showed 7.2 percent of municipalities expect to miss that deadline, due in large part to a dearth of doctors and nurses to administer shots. Technical issues with taking reservations have also hampered the effort.
Calling vaccines an "ace in the hole" in bringing the pandemic under control, Suga told reporters Friday he will strive to deliver them to as many people as possible, as quickly as possible.
Japan has supply agreements to receive 50 million doses of the COVID-19 vaccine from Moderna by September, 120 million doses from AstraZeneca, and 194 million doses from Pfizer.
On Thursday, a drug safety panel at the health ministry signed off on the vaccines developed by AstraZeneca and Moderna, which had applied for approval in February and March, respectively.
The Moderna vaccine uses a new technology called messenger RNA, or mRNA. Pfizer's is the same type, while the AstraZeneca vaccine uses a harmless version of a common cold virus.
The AstraZeneca vaccine has a slightly lower efficacy rate than the other two -- 70 percent compared with 94 percent for Moderna and 95 percent for Pfizer.
That is still higher than between 40 and 60 percent efficacy for influenza vaccines, and the AstraZeneca shot has the advantage of being storable in refrigerators between 2 and 8 C, making it easier to distribute than its rivals, which must be kept in freezers at temperatures as low as around minus 75 C.
But some countries have temporarily suspended the use of the AstraZeneca vaccine or restricted its use on younger people due to the rare instances of blood clots.
Given Japan has already secured enough of the Pfizer and Moderna vaccines to cover people aged 16 or older, the health ministry will also consider imposing age limits after further review.
Meanwhile, a senior government official said the mass vaccination center in Tokyo, originally slated to open Monday and run for three months, will stay open after August.
The center is set to serve residents of the capital and neighboring Kanagawa, Chiba and Saitama prefectures, administering up to 10,000 shots per day.