TOKYO -- The fate of roughly 120 million doses of AstraZeneca's COVID-19 vaccine remains up in the air in Japan after the government paused the rollout the very same day it gave the green light for emergency use.
With Japan lagging behind such countries as the U.S. in vaccinations, Tokyo's mixed messages have drawn criticism. Still, the vaccine's road to real-world deployment remains rocky as fears over its potential side effects loom large.
The health ministry on Friday formally cleared the AstraZeneca vaccine for emergency use in Japan. The screening process, which evaluates efficacy and safety based on clinical trial data, is usually the single biggest hurdle for new shots to become available in Japan.
The ministry acknowledged that AstraZeneca's vaccine was 70.42% effective in clinical trials and expressed hopes that it would curb the spread of the coronavirus.
Still, the ministry decided the same day against the administration of the AstraZeneca vaccine in Japan, at least for now.
Like other coronavirus vaccines, AstraZeneca's shots are legally classified here as a pandemic emergency measure. They cannot be used until the health ministry expressly tells municipal governments to go ahead -- a move requiring a separate approval process.
This includes a ministry subcommittee on vaccines meeting to discuss the use of AstraZeneca vaccines in Japan in a broader context, based on their efficacy, the supply of alternatives from Pfizer and Moderna, progress in Japan's vaccination drive, and potential side effects.
But uncertainties loom.
There have been reports of people developing rare blood clots after receiving the AstraZeneca vaccine, including some deaths. While the risk of this side effect is extremely low, it tends to appear more frequently in younger age groups.
The U.K. reported 79 cases of these blood clots by the end of March, compared with 20.2 million doses administered. Of the 19 people who died as a result, 11 were younger than 50.
This has led some countries to restrict the vaccine to older recipients -- a potentially infeasible course for Japan.
Japan has been inoculating older adults with the Pfizer vaccine and is set to begin offering the Moderna shot at mass vaccination sites Monday. Between the two, the country has secured enough doses for over 122 million people, more than the 110 million people aged 16 and older for whom vaccines have been authorized.
Given that Japan is already on track to have enough supply to cover its vaccination campaign for seniors, which the government aims to wrap up by the end of July, it would be difficult to use the AstraZeneca shot for older groups as has been tried elsewhere.
The vaccine subcommittee continued discussions Friday on what to do with the vaccine. "It has not been determined" when a decision will be made, the health ministry says.
With many people still waiting for shots, an expert argued at the meeting that no vaccine that has been proved effective should be excluded from consideration.
"The Japanese public, with the exception of the elderly, will not be receiving any vaccines until at least the fall at the rate we are going," Gakushuin University economics professor Wataru Suzuki wrote in commentary for Nikkei. "We may not even get there by the end of the year."
"There is definitely demand among people who want to feel protected from the virus as soon as possible, or who want a vaccine passport so they can travel abroad for work, and the health ministry is going too far by taking the option away," he argued.
The government has struck a deal to procure 120 million doses of the AstraZeneca vaccine. Of these, 30 million are to be produced domestically by Daiichi Sankyo and KM Biologics using undiluted solutions from the U.S.
The imports and production began this spring. Both Daiichi Sankyo and KM were preparing to ship the vaccines upon government approval.
Undiluted solutions for the remaining 90 million doses are to be made in Japan by JCR Pharmaceuticals. The midtier drugmaker has begun the production using equipment and technology from AstraZeneca. JCR has announced plans to build a new factory.
AstraZeneca says its completed vaccines can be refrigerated for at least half a year at temperatures of 2 C to 8 C. At this time, it is uncertain how many ready vaccines have been made.
If there is no decision about where to use the vaccines within the next six months, the stock could expire and be lost.
The U.S. has yet to greenlight the AstraZeneca vaccine. Yet the country has agreed to purchase 300 million doses, and there are batches of ready supplies.
For now, the White House plans to ship unused vaccines elsewhere, which matches a proposal made within the Japanese government.