One of the most common causes of smell loss is a viral infection, such as the common cold, sinus or other upper respiratory tract infections. Those coronaviruses that don’t cause deadly diseases, such as COVID-19, Sars and Mers, are one of the causes of the common cold and have been known to cause smell loss. In most of these cases, sense of smell returns when symptoms clear, as smell loss is simply the result of a blocked nose, which prevents aroma molecules reaching olfactory receptors in the nose. In some cases, smell loss can persist for months and years.

In March 2020, Google searches for phrases like “can’t taste food” or “why can’t I smell” spiked around the world, particularly in areas where COVID-19 hit hardest. Still, many of us have experienced a temporary change in the flavor of our food with a common cold or the flu (influenza). So, is COVID-19 – the disease caused by the SARS-CoV-2 virus – somehow special in the way it affects smell and taste?