Optimal mobility restriction minimizing COVID-19 and excess suicide deaths in Japan

<jats:title>Abstract</jats:title><jats:sec><jats:title>Background</jats:title><jats:p>Strict countermeasures for COVID-19 outbreak such as lockdowns and voluntary restrictions against going out might have reduced mortality because of COVID-19 directly, but might have raised suicide rates.</jats:p></jats:sec><jats:sec><jats:title>Object</jats:title><jats:p>We examined best policies for minimizing overall mortality attributable to COVID-19 directly, and excess mortality by suicide because of COVID-19.</jats:p></jats:sec><jats:sec><jats:title>Method</jats:title><jats:p>We regressed the estimated excess mortality attributable to suicide deaths against mobility-restrictive measures. Mortality attributable to COVID-19 directly was estimated through association between the effective reproduction number and mobility. We sought the best mobility restriction for minimizing overall deaths.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Significant association was found between mobility and suicide, but the data were very few. Results showed the best mobility level as 65.5, which represents a 34.5% reduction in mobility from the normal level.</jats:p></jats:sec><jats:sec><jats:title>Discussion and Conclusion</jats:title><jats:p>An overly restrictive policy inducing lower than optimal mobility led to higher total mortality.</jats:p></jats:sec>