Dear Editor,
We would like to share some ideas related to the recently published article, “Social and Policy Determinants of COVID-19 Infection Across 23 Countries: An Ecological Study” [1]. Coronavirus disease 2019 (COVID-19) transmission can be influenced by social and policy determinants, such as integrated health systems and policy responses to COVID-19, according to Kim et al. [1]. When responding to COVID-19, a variety of socioeconomic and policy issues should be taken into account [1]. We agree that any disease can be impacted by local socioeconomic and policy factors. Regarding the present study, it should further recognize the changing situation of COVID-19. The pandemic has rapidly changed, and the changes in local policies against COVID-19 in different periods of the outbreak might have been different. For example, a setting might primarily rely on an inactivated vaccine, but local policies would change when there is a new emerging variant of severe acute respiratory syndrome coronavirus 2 [2]. If possible, an additional analysis of different policy changes in response to the changing outbreak situation should be performed.