State of Emergency and Human Mobility during the COVID-19 Pandemic

Okamoto, S.

Background To help control the spread of the coronavirus disease 2019 (COVID-19), the Japanese government declared a state of emergency (SoE) thrice. However, these were less stringent than other nations. It has not been assessed whether soft containment policies were sufficiently effective in promoting social distancing or reducing human contact. Methods Utilising the Google mobility index to assess social distancing behaviour in all Japanese prefectures between 15 February 2020 and 12 June 2021, mobility changes were assessed by an interrupted time-series analysis after adjusting for seasonality and various prefecture-specific fixed-effects and distinguishing potential heterogeneity across multiple SoEs and time passed after the declaration. Results The mobility index for retail and recreation showed an immediate decline after the declaration of the SoE by 12.78 percent-points (95%CI: -13.61 to -11.94) and a further decline after the initial period (beta: -0.93, 95%CI: -1.11 to -0.74), but gradually increased by 0.02 percent-points (95%CI: 0.02 to 0.02). This trend was similar for mobilities in other places. Among the three SoEs, the overall decline in human mobility outside the home in the third SoE was the least significant, suggesting that people were less compliant with social distancing measures during this period. Conclusion Although less stringent government responses to the pandemic may help promote social distancing by controlling human mobilities outside the home, their effectiveness may decrease if these interventions are repeated and enforced for extended periods, distorting one's health belief by heuristics biases. By combining these with other measures (i.e. risk-communication strategies), even mild containment and closure policies can be effective in curbing the spread of the virus.