What Impacts Do Human Mobility and Vaccination Have on Trends in COVID-19 Infections? Evidence from four developed countries

This paper examines the dynamics of country-wide coronavirus disease 2019 (COVID-19) infections from an economic perspective using a relatively large and aggregated data set constructed based on publicly available data. Based on the “Residential†category of Google's COVID-19 Community Mobility Reports and the number of new positive polymerase chain reaction (PCR) tests per week per 100,000 population (logarithmic values) using state, provincial, or prefectural panel data from Canada, Germany, Italy, and Japan, we found that vaccinations strongly encouraged people to go outside in all countries except Japan, and that vaccinations reduced the number of new positive PCR tests in Japan and Italy. The results from Japan, where vaccination-induced outreach was relatively low, suggest that a 100% vaccine uptake rate would suppress the number of new positive PCR tests by 0.639-2.951%. We also analyzed the effects of vaccination on economic activities using mobility data as proxy variables. The results indicated that vaccination increases mobility, and that Canada, Germany, and Italy showed stronger effects on promoting outings than did Japan. These findings suggest that governments should continue to inform citizens that the effectiveness of vaccines are limited in terms of suppressing positive cases, implement appropriate risk controls and alerts to avoid forced lockdowns, and promote voluntary stay-at-home behavior to avoid an explosion of positive cases.