Researchers in Japan found a higher incidence of Covid-19 symptoms among people who have participated in a domestic travel campaign promoted by the government, suggesting that it is contributing to a spread in the virus.

The findings will make dismal reading for Prime Minister Yoshihide Suga, who has defended the travel campaign, saying it was needed to stop many small businesses in the hospitality sector from going bust due to the lack of customers as a result of the virus scare...