One type of corona jumped from bat to animal then to human and this virus calling SARS-COV-2 and causes the COVID-19 disease. The COVID-19 is keep increasing day-by-day in all of the world and in the other hand some of discharged patients after recovery show some positive RT-PCR and they think they were infected by same virus again or the virus reactivated again. In this paper, I have demonstrated that reactivation and reinfection will not occur in the same person in a short period of time.