Tokyo Olympics and Paralympics are less than two months away. COVID-19 daily infections are going down in the Japanese capital, but the medical system remains under strain.
New infections have declined, week-on-week, for 13 straight days. But Tokyo's daily average for the past week is still above 600.
Tokyo, Osaka, Hyogo and Kyoto have spent a month under a state of emergency.
The declaration now covers 10 prefectures.
Most will expire within days, but many prefectural leaders don't want to see them lifted.
Tokyo Governor Koike Yuriko says she wants measures extended for about a month.
The coming Olympics adds extra pressure, especially given a so-far sluggish vaccination drive.
Organizers say 1,600 athletes, coaches and delegates will be inoculated, starting on June 1.
The jabs will not come from Japan's stock, as Pfizer is donating them.
IOC President Thomas Bach says at least 80 percent of people staying at the Olympic Village will be inoculated.
There's new data to support the efficacy of vaccines. The US Centers for Disease Control and Prevention says only about 10,000 or 0.01 percent of fully-vaccinated people had reported infections by the end of April. 160 died.
The researchers say this shows the shots are a critical tool for controlling the pandemic.
Officials in Japan are becoming more concerned about the variant strain that's ravaging India.
They've confirmed 29 infections so far, including at least one person who hadn't traveled abroad in weeks.
Tokyo Medical and Dental University's associate professor Takeuchi Hiroaki said, "It's possible the patient came into contact with people who had been infected with the variant first detected in India."
The patient developed severe symptoms, but later recovered.
Japan has been gradually stepping up restrictions on travel from India. But experts warn some people may have developed symptoms after entering the country and spread the virus here.
Health authorities across Japan confirmed more than 4,500 new cases and 116 deaths on Wednesday.