TOKYO -- Japan's health minister pledged Sunday to investigate what caused the deaths of two people injected with coronavirus vaccine from a batch later taken out of circulation due to contamination concerns.
"We're still not clear about the causal relationship" between the deaths and the vaccine contamination, said Norihisa Tamura, the minister of health, labor and welfare. "I wish to conduct a thorough investigation."
Tamura made his comments on a program that aired on NHK, Japan's national broadcaster.
"It's imperative that we prevent a reoccurrence of the contamination," said Tamura. "I intend to promptly communicate to the public any information we uncover."
Two men in their 30s died this month within days of being administered the Moderna vaccine, the health ministry said Saturday. Neither had underlying medical conditions nor a history of allergies, according to the ministry.
Contaminants were reportedly found in a lot of Moderna vaccines labeled 3004667. Along with that batch, the Japanese government suspended vaccines from lots 3004734 and 3004956, which were made in the same production line. In total, 1.6 million doses were pulled.
Both men died after taking doses from lot 3004734.
The state of emergency declared in Tokyo and other prefectures is due to expire on Sept. 12. But lifting the emergency will "probably be pretty difficult considering the present situation," Tamura said during the same NHK program.
For Tokyo alone, daily case numbers must fall below 500 before the emergency declaration can be lifted, said Tamura. Tokyo confirmed 3,081 cases on Sunday.
Meanwhile, Japan's vaccine czar, Taro Kono, said booster shots would be offered "at the end of October or November at the soonest."
Japan is slated to receive 10 million doses from Pfizer between October and December. "Healthcare workers can take their third doses" from that batch, Kono said on a separate TV program.
The U.S. recently announced a plan to provide booster shots to those who received their second dose of the Moderna or Pfizer vaccines eight months prior. Japan started vaccinating frontline health workers in February, meaning they can be eligible for boosters as early as October, Kono said.
Kono, whose official title is the minister for administrative reform and regulatory reform, also touched on the long queues that formed at a reservation-free vaccination center in Tokyo targeting younger people and recently opened by the metropolitan government.
"Having no reservation is ill-advised," said Kono. "I believe it's better to get a reservation or be selected through a lottery. I seek to proceed in a manner in which there is no waste."
Kono is among the most popular choices to be Japan's next prime minister, according to opinion polls taken by Nikkei. Kono has been coy about expressing a desire to run for president of the ruling Liberal Democratic Party, whose leadership race is scheduled for September.
"For now, I wish to fully accomplish my job as a cabinet minister," Kono said.