A Japanese research team says the "Go To" travel campaign launched last July may have contributed to the spread of the coronavirus in its initial phase.
The group led by Kyoto University Professor Nishiura Hiroshi published a paper in the Journal of Clinical Medicine.
They analyzed approximately 4,000 cases reported by 24 prefectures between May and August 2020. They found that about 20 percent of these cases involved people who had either used the travel program or been in close contact with such travelers before showing symptoms.
A more detailed analysis shows that 127 travel-related cases were found in the first five days of the campaign. This was 1.44 times higher than the figure for the same period a week earlier.
The figure for sightseeing trips was 2.62 times higher.
The group says it cannot conclude that the campaign led to the spread of the virus due to the differences in publicly available information for each region, but it could have done so, at least at the beginning.
The group says more scientific evidence is needed to find the right balance between controlling infections and normalizing business activity.