COVID-19 Infection risk posed by drinking alcohol at restaurants or bars in Japan

<jats:title>Abstract</jats:title><jats:sec><jats:title>Background</jats:title><jats:p>On April 25, 2021, the third state of emergency was declared in Japan. Drinking alcohol at restaurants and bars was banned.</jats:p></jats:sec><jats:sec><jats:title>Object</jats:title><jats:p>We used published data to evaluate drinking ban effects.</jats:p></jats:sec><jats:sec><jats:title>Method</jats:title><jats:p>We bootstrapped the data and evaluated the risk ratio for drinking compared with non-drinking during group dining with similar frequency and numbers of participants.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>The 99% lower bound of the bootstrapped distribution of the risk ratio was less than one. Therefore the null hypothesis, that incidence in the two styles of group dining were the same, cannot be rejected.</jats:p></jats:sec><jats:sec><jats:title>Discussion and Conclusion</jats:title><jats:p>Results constitute no clear evidence indicating a risk of drinking alcohol in groups. However, further analyses using collected data are necessary. Moreover, risks posed by the number of group diners or their dining frequency must be evaluated.</jats:p></jats:sec>