New coronavirus positive-to-negative and positive again may be due to incomplete treatment or re-emergence of viral infection. 1. Incomplete treatment: patients infected with the new coronavirus are hospitalized, and after relevant treatment, the amount of detoxification in the body gradually decreases, and false-negative results may appear in the nucleic acid test; if the medication is stopped at this time, the virus may still continue to multiply in the body, and then a positive conversion may occur. 2. Re-infection: the patient has completely recovered after professional treatment, and there is no abnormality found in the nucleic acid test. If the patient does not pay attention to their own protection after discharge from the hospital, or due to low resistance, there is still a possibility of re-infection with the new coronavirus, which will turn positive. Patients who are positive to negative and then turn positive for the new coronavirus should be isolated in time and treated accordingly. Normally, appropriate participation in physical exercise, is conducive to improving their own immunity. In addition, when you go out, wear a good mask, good protection, to avoid re-infection.