Table 2.
Frequency and severity of symptoms
| PCS/non-ME/CFS (n = 23) | PCS/ME/CFS (n = 19) | non-COVID ME/CFS (n = 17) | non-COVID ME/CFS vs. PCS/non-ME/CFS | non-COVID ME/CFS vs. PCS/ME/CFS | PCS/non-ME/CFS vs. PCS/ME/CFS | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| %PCS patients | Median | Range | % PCS/CFS patients | Median | Range | % ME/CFS patients | Median | Range | p | P | p | |
| Fatigue | 100 | 7 | (2–10) | 100 | 8 | (5–10) | 100 | 8 | (5–10) | 0,05 | n.s. | n.s. |
| PEM | 100 | 6 | (1–9) | 100 | 8 | (5–10) | 100 | 9 | (7–10) | *** | n.s. | n.s. |
| Need for rest | 96 | 7a | (2–10) | 100 | 8 | (5–10) | 94 | 8,5a | (7–10) | n.s. | n.s. | n.s. |
| Impaired performance | 96 | 8a | (3–10) | 100 | 8 | (4–10) | 100 | 8 | (5–10) | n.s. | n.s. | n.s. |
| Stress intolerance | 96 | 6a | (2–10) | 100 | 8 | (3–10) | 94 | 9a | (8–10) | *** | n.s. | n.s. |
| Muscle pain | 83 | 4a | (1–9) | 84 | 5 | (1–10) | 88 | 7 | (1–10) | n.s. | n.s. | n.s. |
| Headache | 87 | 5 | (1–10) | 95 | 5a | (1–9) | 94 | 7a | (4–9) | n.s. | n.s. | n.s. |
| Joint pain | 78 | 3a | (1–9) | 89 | 3 | (1–10) | 76 | 4 | (0–8) | n.s. | n.s. | n.s. |
| Memory/word finding problems | 70 | 5a | (1–8) | 100 | 5 | (2–7) | 88 | 5a | (1–8) | n.s. | n.s. | n.s. |
| Concentration impairment | 91 | 5 | (1–9) | 100 | 6 | (3–9) | 100 | 7 | (4–9) | n.s. | n.s. | n.s. |
| Mental fatigue | 100 | 7 | (2–10) | 100 | 6 | (4–10) | 100 | 8 | (5–10) | n.s. | n.s. | n.s. |
| Visual disturbances | 48 | 1.5a | (1–6) | 63 | 3 | (1–6) | 71 | 3 | (1–9) | n.s. | n.s. | n.s. |
| Palpitations | 70 | 4a | (1–9) | 89 | 5 | (1–10) | 94 | 5 | (0–10) | n.s. | n.s. | n.s. |
| Dizziness when standing up | 83 | 4a | (1–8) | 84 | 5 | (1–10) | 94 | 5 | (1–10) | n.s. | n.s. | n.s. |
| Dizziness when walking | 61 | 2.5a | (1–9) | 68 | 3.5a | (1–7) | 88 | 4 | (1–10) | n.s. | n.s. | n.s. |
| Sleep disturbances | 83 | 6.5a | (1–10) | 89 | 7 | (1–10) | 94 | 8 | (1–10) | n.s. | n.s. | n.s. |
| Hypersensitivity to temperature | 48 | 1.5a | (1–8) | 79 | 5 | (1–8) | 88 | 7 | (1–10) | ** | n.s. | n.s. |
| …. to light | 52 | 2a | (1–7) | 84 | 5 | (1–10) | 88 | 5 | (1–10) | n.s. | n.s. | n.s. |
| …. to noise | 70 | 3a | (1–9) | 89 | 5 | (1–10) | 88 | 7 | (1–10) | n.s. | n.s. | n.s. |
| Breathing difficulty | 70 | 5 | (1–10) | 79 | 5 | (1–10) | 47 | 1.5a | (1–8) | n.s. | n.s. | n.s. |
| Irritable bowel | 48 | 2b | (1-10) | 79 | 5 | (1–9) | 82 | 6 | (1–10) | n.s. | n.s. | n.s. |
| Fever | 17 | 1 | (1–3) | 21 | 1a | (1–10) | 35 | 1a | (1–5) | n.s. | n.s. | n.s. |
| Painful lymph nodes | 30 | 1 | (1–7) | 32 | 1 | (1–9) | 71 | 3.5a | (1–7) | n.s. | n.s. | n.s. |
| Sore throat | 57 | 2 | (1–7) | 63 | 3 | (1–7) | 82 | 6 | (1–9) | n.s. | n.s. | n.s. |
| Flu-like symptoms | 70 | 3a | (1–10) | 79 | 5 | (1–8) | 100 | 8 | (4–9) | ** | * | n.s. |
Symptom severity was assessed on a scale of 1–10 (none to most severe) in PCS cohorts and non-COVID ME/CFS. Data were analyzed using nonparametric all-pairs Dunn-type multiple contrast tests. P values were adjusted for multiplicity across symptoms with the Benjamini-Hochberg (BH) correction, statistically significant comparisons are indicated by asterisks as: *<0.05; **<0.01; ***<0.0001, not significant comparisons are indicated as n.s. Source data are provided as a Source Data file.
PCS/non-ME/CFS post-COVID-19 syndrome/non-myalgic encephalomyelitis/chronic fatigue syndrome, PCS/ME/CFS post-COVID-19 syndrome/myalgic encephalomyelitis/chronic fatigue syndrome, non-COVID ME/CFS non-COVID-19 myalgic encephalomyelitis/chronic fatigue syndrome.
an = ntotal−1.
bn = ntotal−2.