TOKYO -- Japan began vaccinating Self-Defense Forces members against the coronavirus Monday, readying the emergency and national security responders to mobilize for the floods and typhoons common in the summer.

The country has fallen behind others in inoculating defense personnel, who generally live and train in groups and face a higher risk of COVID-19 clusters.

The strengthened program took advantage of open appointments at an SDF-run mass vaccination site in Tokyo, where 1,650 slots for Monday remained unfilled the day before.

SDF members in the greater Tokyo area, including those ready for deployment to emergencies, received shots Monday. The rollout for SDF personnel will also begin at an Osaka mass vaccination center for slots still open the day prior. Police, firefighters and Japan Coast Guard personnel are eligible as well.

At the two vaccination sites, 65% of appointments for June 15 to June 27 had remained unfilled as of 5 p.m. on Monday. Appointments are offered to those 65 and older living anywhere in the country.

Japan's 220,000-plus SDF members as a whole are not a priority group, except for doctors and nurses. Defense personnel will become eligible after the rollout begins for people 64 and younger.

A member of the Ground Self-Defense Force receives a COVID shot at a mass vaccination site in Tokyo. (Photo courtesy of Japan GSDF)   © Kyodo

In the U.S., Canada, Germany, Spain, South Korea and Indonesia, service members are vaccine priority groups behind the likes of older adults and health care workers, according to local governments and media reports.

But Japan has apparently changed tack with the approach of the summer, when the country is typically hit with devastating typhoons and torrential rains. Emergency response stands to suffer if an outbreak keeps SDF members from being mobilized.

Military personnel are prioritized in Russia and China as well. Russia authorized its first homegrown COVID-19 vaccine last August and began inoculating service members and their families in late November, ahead of health care workers. More than 90% of those eligible, or more than 800,000 people, have received their shots.

In March 2020, an outbreak on a nuclear-powered U.S. Navy aircraft carrier forced the warship out of service.

Japan's ruling Liberal Democratic Party urged the government this month to prioritize vaccination for all SDF members, saying personnel deployed abroad are "constantly concerned about coronavirus infection risk while at work," in contrast to their foreign peers.