What exactly is COVID-19?

Much is written about what is characteristic of the disease COVID-19. Some claim that it is a common cold, some say flu, some say pneumonia, some list various symptoms such as fever, cough, fatigue, loss of sense of smell, etc.

This is the CDC's definition.

Because the symptoms are so varied and thus difficult to interpret, the practice has become that any disease in which the patient has simultaneously tested positive for SARS-CoV-2 or because of the circumstances is suspected of being infected with SARS-CoV-2 is designated as COVID-19. We've written about this before, read more about it here.

COVID-19 is thus not a disease but an administrative concept.