The fact that the new crown has not turned negative after twenty days may be related to factors such as larger viral load, more serious condition, and re-positive. 1. Large viral load, after the occurrence of new crown infection, different infected people due to autoimmune and other reasons lead to different viral load in the body, if the viral load in the body is too large, the general treatment measures are relatively mild, which may cause a longer period of time is still positive. 2. More serious disease, mainly seen in the older, combined with serious underlying diseases of the population, autoimmunity is relatively poor, at the same time the lung shadow progresses faster, which leads to greater difficulty in treatment, and the nucleic acid test for a long time also failed to turn negative. 3. Reactivation, part of the population after the first infection is cured by treatment, two consecutive negative nucleic acid test again after the infection, resulting in reactivation. If the new crown has not turned negative after twenty days, you can consult a professional physician for timely advice and reasonable treatment.