1 in 20 COVID survivors may have condition characterized by extreme fatigue The percentage of all participants who had ME/CFS post-infection was 4.5%, compared with 0.6% of controls. Post-exertional malaise was the most common symptom in both acute-infected (15.9%) and post-acute–infected participants (29.1%), followed by positional dizziness (14.4% and 25.0%, respectively).  CIDRAP

...

ME/CFS, which can be triggered by viral and non-viral infection, causes severe fatigue for at least 6 months and may entail impaired memory, brain fog, dizziness, and muscle or joint pain. Physical or mental activity exacerbates symptoms, which aren't fully relieved by rest.

...