A hospital worker in central Japan who has received two vaccine shots was confirmed Sunday as infected with the novel coronavirus, as the country reported 2,777 daily cases with Tokyo and Osaka Prefecture continuing to see a rebound in infections.

Local authorities said the temporary staffer at a hospital in Ishikawa Prefecture had received doses of the vaccine developed by Pfizer Inc. on March 13 and April 3. The person has not shown any symptoms yet, they said.

People wearing masks to protect against the novel coronavirus walk in Tokyo's Ginza shopping district on April 11, 2021, a day before quasi-emergency measures against the virus officially commence in the capital. (Kyodo) ==Kyodo

"In general, it takes time before antibodies are produced following vaccination," a prefectural government official said.

Japan started vaccinations for health care workers in February. The U.S. pharmaceutical company's vaccine is administered twice, three weeks apart.

The worker took a test after coming into contact with an infected person. According to the hospital, the person does not deal with patients.

Also Sunday, Tokyo reported an additional 421 coronavirus cases, a day before the metropolitan government imposes stricter measures to prevent the spread of the virus.

Osaka Prefecture confirmed 760 daily cases, lower than its record 918 marked the previous day, amid worries that the western prefecture and the wider Kansai region is experiencing a surge of more contagious coronavirus variants.

In Tokyo, the latest figure brought the cumulative total in the capital to 125,978 and the seven-day rolling average of infections to 468, up 20.1 percent from the previous week.

The metropolitan government will start imposing tougher prevention measures in many parts of Tokyo on Monday, including asking restaurants and bars in densely populated areas to close by 8 p.m.

But the steps will be implemented without the central government declaring a state of emergency. Japan last month fully lifted a second coronavirus state of emergency that had been in place since January in Tokyo and other areas.

The quasi-emergency measures were introduced on April 5 in Osaka, Hyogo and Miyagi prefectures. Prime Minister Yoshihide Suga decided Friday to add Tokyo, Kyoto and Okinawa to the list of areas covered.