The Tokyo Metropolitan Government said that 178 people had tested positive for the virus in the last 24 hours, out of 5,197 tests.

It is an indication that authorities in the Japanese capital are starting to have success in their attempts to contain the spread of the virus, although nationally the seven-day average of daily deaths remains above 70.

November 24 was the last time Tokyo - which remains under a state of emergency - reported fewer than 200 new COVID-19 cases in a day.

While the International Olympic Committee and Tokyo 2020 remain adamant the Games will go ahead as planned in the Japanese capital this year, an upturn in the health situation increases the likelihood of that happening.

Crucially, it may also lead to increased public support for the Olympics and Paralympics.

Recent polls have suggested the majority of Japanese people believe the event should either be postponed again or cancelled.

The rollout of a vaccination programme is another welcome development for Tokyo 2020, but Japan's Vaccine Minister Taro Kono yesterday warned that inoculation of the elderly would only start "little by little" because of a shortage of the Pfizer-BioNTech vaccine until May.

That vaccine - which needs to be stored in an ultra-cold freezer - was approved for use in Japan earlier this month, and the country has started to vaccinate healthcare workers.

The Olympic Opening Ceremony is scheduled for July 23, and a decision on whether spectators will be able to attend events is yet to be taken.

An athletes' playbook written by organisers spells out how they can be expected to be tested for COVID-19 at least every four days, must wear a face covering when not competing, eating or training, will be expected not to to shout or sing and also must arrive in Tokyo no earlier than five days before their event and depart a maximum of two days after.