The effect of silent eating during school lunchtime on COVID-19 outbreaks.

Silent eating-no talking during mealtimes-has been used as a measure to reduce the spread of the COVID-19 infection because the emission of droplets during conversations has been considered a risk factor for spreading the virus. Japan implemented silent eating during school lunchtimes in May 2020, and it remained in effect until November 2022. However, concerns have been raised regarding its potential negative effects on children's well-being and educational attainment. More importantly, no study to date has examined its effectiveness in reducing the risk of COVID-19 outbreaks. This study aims to address this important knowledge gap by examining the impact of silent eating on the risk of COVID-19 outbreaks. In November 2022, the Japanese government announced that silent eating in public schools was no longer needed, which resulted in discontinuation of the measure in some schools while other schools maintained it. Taking advantage of this cancelation of the silent eating requirement as a natural experiment, we investigated whether silent eating was associated with a reduced risk of COVID-19 outbreaks. We measured the probability of class closures in public schools (the government's guidelines required class closure when more than one child was infected with COVID-19) by applying a Difference-in-Differences model with two-way fixed effects to panel data. We found no evidence that silent eating was associated with a reduced probability of class closures. Heterogeneity analysis also revealed that our findings did not vary by school characteristics. Our findings indicate that policymakers should be cautious about using silent eating at schools as a potential lever to control outbreaks of infectious diseases.