Japan began administering COVID-19 vaccine on Wednesday, starting with hospital staff in the Tokyo metropolitan area before expanding the rollout nationwide as the clock ticks down to the Summer Olympics and Paralympics.

The country has been slow to launch vaccinations against the coronavirus, starting its program later than around 80 other countries as Prime Minister Yoshihide Suga faces criticism of a sluggish pandemic response.

Kazuhiro Araki (L), head of the Tokyo Medical Center, is administered a COVID-19 vaccine at his hospital in Tokyo's Meguro Ward on Feb. 17, 2021, receiving the first shot under Japan's vaccination program against the novel coronavirus. Japan is starting with an initial group of 40,000 health workers before expanding the rollout to the elderly and people with preexisting conditions. (Pool photo) (Kyodo) ==Kyodo

A total of 125 staff members were inoculated at eight hospitals in and around the capital on Wednesday, with the vaccine developed by U.S. drugmaker Pfizer Inc. and Germany's BioNTech SE due to be administered at 100 medical facilities across the country by next week.

Speaking in a parliamentary committee meeting, Suga reiterated that vaccines will be the "decisive factor" in fighting the coronavirus and vowed to move forward with the rollout while keeping the public informed.

Of the initial group of 40,000 health workers, 20,000 will participate in a study to track side effects potentially caused by the vaccine and the frequency with which they occur. They will be asked to keep daily records for seven weeks after taking the first of two shots. The shots will be administered three weeks apart.

A health worker injects COVID-19 vaccine from a bottle into a syringe at the Tokyo Medical Center in Tokyo's Meguro Ward on Feb. 17, 2021. Japan began COVID-19 vaccinations the same day, with the first shots given at the state-run hospital. (Pool photo) (Kyodo) ==Kyodo

Twelve staffers, including three doctors and five nurses, were inoculated at the state-run Tokyo Medical Center on Wednesday. Hospital head Kazuhiro Araki, who was first in the country to receive the shot, said he hopes participating in the study will "help both staff and patients prevent infections."

No severe side effects were immediately reported from any of the eight hospitals.

A further 3.7 million front-line health workers are to begin being inoculated in March, followed by 36 million people aged 65 or older from April.

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People with preexisting conditions such as diabetes or heart disease and those working at elderly care facilities will come next, and then finally the general population.

Japan is starting its vaccine rollout more than two months after Britain and the United States. Asked in the House of Representative's Budget Committee session about the cause of the delay, Suga accepted the criticism and admitted that the need to conduct clinical trials domestically had held up the process.

The minister in charge of vaccination efforts, Taro Kono, said Tuesday that foreign residents will become eligible for the free shots in the same order of priority as Japanese citizens.

Japan received the first shipment of about 386,000 doses from Pfizer's factory in Belgium last week and granted fast-track approval for domestic use on Sunday.

Kono said at a press conference that the second shipment had been cleared by the European Union under its new vaccine export controls and was expected to arrive next week but declined to say how many doses it would contain.

Late-stage clinical trials showed the Pfizer vaccine to have an efficacy rate of around 95 percent, compared with 40 to 60 percent for influenza vaccines. Japan also has supply deals with AstraZeneca Plc and Moderna Inc. to receive enough doses for its population of 126 million.

But public skepticism could be a hurdle for Japan's vaccine rollout, with only 63.1 percent of respondents in a Kyodo News poll conducted this month expressing willingness to get a shot, while 27.4 percent said they were unwilling, apparently out of concern for side effects.

The head of the Japan Medical Association, Toshio Nakagawa, on Wednesday called on people to be inoculated when their turn comes, saying, "It's clear that the merits outweigh the demerits."