Korea: Text alerting on COVID-19 outbreak areas/zones
sciencedirect.com (05.05.2020) One of the most effective ways that the Korean government rapidly dispersed these daily updates is emergency SMS messages. All citizens receive daily alert messages through their mobile phones from their local authorities. The alert message arrives with a 40–60 db alarm sound, and contains information from KCDC about newly confirmed patients and their recent trajectories if available.