Olfactory anosmia is the complete loss of the sense of smell, while hyposmia is the partial loss of smell. SARS-CoV-2 is the pathogen responsible for COVID-19. The virus is composed of the membrane, envelope, and spike protein. In the physiology of smell, odoriferous substances bind to proteins secreted by sustentacular cells to be processed by olfactory receptor neurons. Olfactory dysfunction is one of the main manifestations of COVID-19. The duration of persistent symptoms in long COVID is longer in patients who presented severe symptoms compared to those with mild or moderate disease. Therefore, all known risk factors for severe COVID-19, such as obesity or advanced age, fit the risk profile for long COVID.