A muffled voice is not a symptom of the novel coronavirus. The novel coronavirus can cause respiratory tract infections, which mainly refer to the symptoms of the trachea and lungs, and the patients mainly show high fever, cough, sputum, and even severe respiratory distress. Some patients also have non-specific symptoms, such as nausea, vomiting, fatigue, diarrhea. Mute voice belongs to pharyngitis and pharyngolaryngitis of the upper respiratory tract, which is rare in patients with novel coronavirus infection. If your voice is muffled, you should first consider whether the pharyngitis or pharyngolaryngitis is caused by a cold and treat the cold accordingly.