New COVID-19 cases in Japan's capital plummet to 11-month low, but health officials not sure why

Almost overnight, Japan has become a stunning, and somewhat mysterious, coronavirus success story.

Daily new COVID-19 cases have plummeted from a mid-August peak of nearly 6,000 in Tokyo, with caseloads in the densely populated capital now routinely below 100, an 11-month low.

The bars are packed, the trains are crowded, and the mood is celebratory, despite a general bafflement over what, exactly, is behind the sharp drop.

Japan, unlike other places in Europe and Asia, has never had anything close to a lockdown, just a series of relatively toothless states of emergency.

Some possible factors in Japan's success include a belated but remarkably rapid vaccination campaign, an emptying out of many nightlife areas as fears spread during the recent surge in cases, a widespread practice, well before the pandemic, of wearing masks and bad weather in late August that kept people home.

But with vaccine efficacy gradually waning and winter approaching, experts worry that without knowing what exactly why cases have dropped so drastically, Japan could face another wave like this summer, when hospitals overflowed with serious cases and deaths soared — though the numbers were lower than pre-vaccination levels.

Many credit the vaccination campaign, especially among younger people, for bringing infections down. Nearly 70 per cent of the population is fully vaccinated.