The relationship between new PCR positive cases and going out in public during the COVID-19 epidemic in Japan

Takahashi, H.; Terada, I.; Higuchi, T.; Takada, D.; Shin, J.-h.; Kunisawa, S.; Imanaka, Y.

Suppression of the first wave of COVID-19 in Japan is assumedly attributable to people's increased risk perception by acquiring information from the government and media reports. In this study, going out in public amidst the spread of COVID-19 infections was investigated by examining new polymerase chain reaction (PCR) positive cases of COVID-19 and its relationship to four indicators of people going out in public (the people flow, the index of web searches for going outside, the number of times people browse restaurants, and the number of hotel guests), from the Regional Economic and Social Analysis System (V-RESAS). Two waves of COVID-19 infections were examined with cross-correlation analysis. In the first wave, all four indicators of going out reacted oppositely with the change in new PCR positive cases, showing a lag period of -1 to +6 weeks. In the second wave, the same relationship was only observed for the index of web searches for going outside. These results suggest that going out in public could not be described by new PCR positive cases alone in the second wave, even though they could explain people going out to some extent in the first wave.