Thread by @VincentRK

What on earth is long COVID?

1/ Long Covid is loosely defined as symptoms persisting weeks after COVID. Everyone has their own definition.

First, there is no single disease called "Long COVID".
Its a colloquial term given to a variety of conditions following COVID.

See thread

2/ There is a whole lot of problems and diseases that can occur after COVID. Unless we define which exact problem among this heterogenous group of conditions we are talking about we will get absolutely nonsense results.

3/ For some people "long covid" consists of continuation of symptoms of covid lung infection and resultant decrease in lung function: shortness of breath, fatigue, cough.

4/ For some people the immunosupression after COVID predisposes them to recurrent unrelated infections.

5/ For some it is side effects of various treatments — and we do use a lot of proven and unproven treatments in this disease.

6/ For some it is a consequence of thrombotic complications that happened with COVID. There are clots that can occur anywhere. And they cause a variety of symptoms depending on location.

Or a consequence of being in the ICU alone on a ventilator...

7/ For some especially those whose initial covid illness was mild, it's an autoimmune or idiopathic process causing everything from joint pains to brain fog

If we restrict "long COVID" definition to this group, we will miss people who get the same problems but had severe disease

8/ The key is to recognize the term "long COVID" is like fever. A symptom, not a disease, and one that has many causes. We need to define each, & estimate the incidence, prevalence, prognosis, and treatment of each. Otherwise we will get a bunch of meaningless numbers & theories