Before revision:  In this vision paper we propose CovidSens, the concept of social-sensing-based risk alerting systems to notify the general public  about the COVID-19 spread  .
After revision:  In this vision paper we propose CovidSens, a vision of social sensing based risk alert systems to spontaneously obtain and analyze social data to infer COVID-19 propagation. CovidSens can actively help to keep the general public about the COVID-19 spread .