Japan is unlikely to inoculate as many people with Pfizer Inc.'s COVID-19 vaccine as planned due to a shortage of special syringes capable of extracting the final dose from vials provided by the drugmaker, health minister Norihisa Tamura said Tuesday.

The country said last month that it had secured doses for 72 million people based on the assumption that each vial could provide six shots. But without low dead space syringes, which minimize the amount of vaccine left in the syringe after use, a vial ends up yielding only five doses -- enough for 60 million people.

A person receives a shot of vaccine developed by U.S. pharmaceutical company Pfizer Inc. on Jan. 14, 2021, in Madrid. (Getty/Kyodo)

"The syringes used in Japan can only draw five doses. We will use all the syringes we have that can draw six doses, but it will, of course, not be enough as more shots are administered," said Tamura. The government is requesting medical equipment manufacturers step up production of the special syringes.

Reuters reported last month that the United States and European Union countries have also been scrambling to secure enough low dead space syringes to squeeze more doses from the Pfizer vaccine, with manufacturers urged to boost their overall production capacity.

Top government spokesman Katsunobu Kato said Monday that the sixth dose will generally "be discarded" if it cannot be extracted.

Yoshinori Oguchi, a member of the ruling party's junior coalition partner Komeito, has said the government should have assumed each vial could only provide five doses when securing vaccines for 72 million people.

Provided Japan does not change the number of vials ordered from Pfizer, it will revise the number of doses it can deliver to 120 million, according to government sources.

The government is set to discuss with Pfizer how many more doses it can supply to Japan, a senior health ministry official said.

The Pfizer vaccine, already under review by the health ministry, is expected to gain approval on Feb. 15 when the ministry holds a panel meeting. Britain's AstraZeneca Plc, meanwhile, has said it has formally filed a request to the ministry for approval of its vaccine.

The government plans to begin inoculating health workers from Feb. 17 in a study to verify the vaccine's safety before commencing vaccinations of around 36 million people aged 65 and older from April.