Why is nasal swab better than oral swab to detect Covid-19? What is the difference between nasal cavity swab and oral swab? According to Deputy Chief Physician Cai Yuexin, some areas of the pharynx include nasopharynx, oropharynx, and laryngopharyngeal. The mucous membranes of the three are continuous and belong to the area of ?the upper respiratory tract. Nasal swabs and …