Photo/Illutration Workers at a Tokyo facility provide care for senior citizens. (Provided by Izumiwakuie)

Experts say the slow rollout of COVID-19 booster shots can largely be blamed on a sudden revision in inoculation timetables brought about by the emergence of the infectious Omicron variant late last year.

The health ministry’s abrupt change in how long cities had to wait after administering the second dose before giving the third has caused havoc to the booster campaigns carried out by Japan’s most populated cities.

Government officials had at one time pledged to complete giving booster shots to all senior citizens who wanted one by the end of February. But a week into March, only about 60 percent of all those 65 and older have received the third jab.

The situation is much more dire in major cities with large populations.

Yokohama, which lies southwest of Tokyo, has a population of about 3.76 million, of which about 900,000 are seniors.

As of March 7, only 16.7 percent of Yokohama’s seniors have gotten the booster shot, the lowest ratio among 20 major cities.

Initially, ministry officials instructed local governments to provide the booster shots eight months after the second jab.

That was because many other nations were using that same schedule for rolling out booster shots for their own populations.

Discussions among Japanese experts on the wait time between second and third jabs began in late summer 2021, and those specializing in infectious diseases pointed out that the preventive effect of the vaccine decreases after about six months.

But because some local governments were still trying to complete administering the second jabs, others familiar with the situation on the ground in those places said there would not be enough time for officials to prepare if the boosters were given out just six months after the second shot.

That led the health ministry to inform local governments in September that they should prepare to administer the booster shots eight months after the second shot.

But just a few months later, the ministry changed course. 

When the more contagious Omicron variant emerged in late November, studies found that the effectiveness of the vaccines decreased much more than experts initially believed. So, the health ministry shortened the gap period between the second and third jabs to six months on Dec. 17.

That change meant logistic problems for large cities such as Yokohama.

When the first two vaccines were given out last year, many Yokohama residents experienced problems making reservations for a shot because the number of inoculation tickets mailed out to residents far exceeded the available number of vaccines.

Learning from that lesson, Yokohama officials decided to mail out the tickets for the booster shots depending on when residents had received their second shot. That meant between 200,000 and 300,000 tickets were mailed out for each period for people to book their appointments.

But when the central government revised the timeline to allow for earlier booster shots, Yokohama officials had to turn on a dime and alter their schedules for printing and mailing out the vaccine tickets.

An official overseeing the process said it was not easy to suddenly change how many tickets would be mailed out at the last minute, particularly when hundreds of thousands of tickets were involved.

Cities with smaller populations have been able to handle the health ministry’s policy change more flexibly.

Sendai, in the northern prefecture of Miyagi, has a population of about 1.06 million, but 28.1 percent of its seniors have received the booster shot, the fifth highest ratio among major cities.

Not only was Sendai able to quickly adapt to the central government’s new timetable, but cooperation among about 400 medical institutions and the city’s own mass vaccination center contributed to its much higher proportion of people who have gotten their boosters.

(This article was compiled from reports by Nanako Matsuzawa, Chihito Shin, Yuki Edamatsu, Tomoe Ishikawa and Miki Morimoto.)

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