One form of control would be a representative part of the population who are NOT post-covid. The null hypothesis argument would be: how many of these cases wou

One form of control would be a representative part of the population who are NOT post-covid. The null hypothesis argument would be: how many of these cases would be present independent of covid infection status? For example, the circumstances of this pandemic have notably increased anxiety and depression rates as well as increasing stress. How many people might have symptoms like fatigue, brain fog, aches, and other inflammation explainable just by this stressful environment even without viral exposure?