Why have COVID-19 cases in Tokyo plummeted? Study points to restraint by the unvaccinated.

Since the peak of the capital’s largest wave of infections, many unvaccinated people have stayed away from places where the virus can spread more easily, such as bars and pubs, a metropolitan government’s researcher has said.

The importance of avoiding such hot spots has been gaining traction since a U.S. study showed just a fraction of places account for the overwhelming majority of infections. The study led by a Stanford University team and other researchers analyzed mobile-phone GPS data and mapped the hourly movements of 98 million people to points of interests such as full-service restaurants and religious establishments.

In the Chicago metropolitan area, for example, 10% of public places, such as restaurants that serve alcohol and hotels, accounted for 85% of the predicted infections, according to the study that has been published in the science and technology journal Nature.

Globally, such has proven to be a reliable indicator that corresponds closely with new COVID-19 infection figures and the virus’s basic reproduction number, which measures the pathogen’s transmissibility. To find similar patterns in the capital, the Tokyo Metropolitan Institute of Medical Science analyzed GPS data to track the movements of people in seven major entertainment areas of Tokyo, including the red-light Kabukicho district, the famous Shibuya Center Street shopping arcade and Roppongi.

The analysis showed that the number of people who went out at night in those potential hot spots has stayed low even over a pair of national holidays this week, while the movements of people in the daytime have been falling for three straight weeks, said Atsushi Nishida, the director of the institute’s Research Center for Social Science & Medicine Sciences. New infection numbers have fallen sharply over the past several weeks, as the majority of residents, including younger people, continue to refrain from dining out in groups, he added.