Japan's Covid-19 infections are falling in contrast with rebounds in other parts of Asia, baffling experts, Reuters reports.

New daily infections have slowed to fewer than one per million people, the least among major economies except for China, and fatalities have fallen to zero in recent days.

However, Prime Minister Fumio Kishida is leaving little to chance as Japan enters its winter months, which last year saw a deadly infection wave that started in the colder north. He ordered borders shut last week to keep out the Omicron variant of the virus, discovered four times so far in Japan.