Social media such as Twitter enable people to interact with each other and share health-related concerns in a new and novel way, as evidenced during the COVID-19 pandemic when in-person communication became inconvenient under social-distancing policies. Little attention has been paid to the impacts of health policy and local political ideology on the trends of spatiotemporal emotions related to COVID-19. This study examines 1) the spatial-temporal clustering trends of negative emotions (or spillover effects); 2) whether health policies such as social distancing policy are associated with spatiotemporal emotion patterns towards COVID-19. This article finds that: 1) COVID-19 related negative emotions detected by social media have spillover effects and that 2) counties with staying at home policy or counties which are predominantly democratic exhibit a higher rate of negative emotional tweets toward COVID-19. These results suggest that scholars and policymakers may want to consider the impacts of interventions caused by public policy and political polarization on spatial-temporal patterns of public health concerns detected by social media.