Table 1. Characteristics of persons, stratified by myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)-like illness and coronavirus disease 2019 (COVID-19) status in Kaiser Permanente Northern California, 2022.
| Characteristic | All | ME/CFS-like illness after COVID-19 | ME/CFS-like illness without prior COVID-19 | No ME/CFS-like illnessa | ||||
|---|---|---|---|---|---|---|---|---|
| nb | % (CI)b | nb | % (CI)b | nb | % (CI)b | nb | % (CI)b | |
| Respondents (n) | 9,825 | 77 | 569 | 9,179 | ||||
| Estimated population size | 2,745,374 | 100 | 6,480 (1,244, 11,715) | 0.24 (0.05, 0.43) | 39,412 (27,467, 51,357) | 1.4 (1, 1.9) | 2,699,482 (2,660,356, 2,738,608) | 98 (98, 99) |
| Any history of COVID-19 | 6,000 | 50 (48, 52) | 77 | 100 | 317 | 48 (34, 63) | 5,606 | 50 (48, 52) |
| ME/CFS diagnosis in EHR or self-report | 1,280 | 0.6 (0.48, 0.77) | 18 | 2.1 (0.83, 5.3) | 173 | 5.8 (2.9, 12) | 1,089 | 0.5 (0.41,0.69) |
| Post-COVID-19 condition diagnosis in EHR | 693 | 0.5 (0.35, 0.81) | 47 | 8.6 (3.4, 20) | 48 | 1.3 (0.85, 2.1) | 598 | 0.5 (0.32, 0.78) |
| ME/CFS-like illness diagnostic criteria c | ||||||||
| Fatigue that fits ME/CFS-like illness diagnostic criteria d | 3,843 | 21 (19, 23) | 77 | 100 | 569 | 100 | 3,197 | 20 (18, 21) |
| Fatigue substantially limits ability to pursue work, educational, social, or recreational activities | 4,128 | 23 (22, 25) | 77 | 100 | 569 | 100 | 3,482 | 22 (20, 24) |
| Does rest make fatigue better? | ||||||||
| Yes, a lot | 2,151 | 26 (24, 27) | 0 | 0 | 0 | 0 | 2,151 | 26 (24, 28) |
| Yes, a little | 3,192 | 26 (24, 28) | 26 | 30 (7.8, 68) | 197 | 46 (32, 61) | 2,969 | 26 (24, 28) |
| No, not very much | 1,957 | 11 (10, 13) | 39 | 65 (28, 90) | 278 | 45 (31, 60) | 1,640 | 11 (9.6, 12) |
| No, not at all | 403 | 1.9 (1.4, 2.4) | 12 | 5.1 (1.4, 17) | 94 | 8.6 (3.7, 18) | 297 | 1.8 (1.3, 2.3) |
| No response | 2,122 | 35 (33, 37) | 0 | 0 | 0 | 0 | 2,122 | 36 (34, 38) |
| Post-exertional malaise that fits ME/CFS-like illness diagnostic criteria d | 1,745 | 5.9 (5.1, 6.9) | 77 | 100 | 569 | 100 | 1,099 | 4.3 (3.6, 5.2) |
| Cognitive impairment that fits ME/CFS-like illness diagnostic criteria d | 1,522 | 7.3 (6.3, 8.3) | 74 | 98 (89, 100) | 536 | 89 (73, 96) | 912 | 5.8 (5.0, 6.9) |
| Unrefreshing sleep or problems sleeping that fits ME/CFS-like illness diagnostic criteria d | 4,214 | 28 (26, 29) | 77 | 100 | 569 | 100 | 3,568 | 26 (25, 28) |
| Orthostatic intolerance that fits ME/CFS-like illness diagnostic criteria d | 346 | 1.4 (0.99, 1.9) | 18 | 4.3 (1.4, 13) | 156 | 34 (21, 50) | 172 | 0.9 (0.59, 1.4) |
| Years since fatigue onset (mean) | 4 (4.0, 4.8) | 2 (1.5, 2.0) | 9 (5.4, 12) | 4 (3.9, 4.7) | ||||
| Age, years (mean) | 50 (49, 50) | 36 (33, 39) | 45 (40, 50) | 50 (49, 50) | ||||
| Age, years | ||||||||
| 18–34 | 1,639 | 26 (24, 28) | 9 | 54 (19, 85) | 86 | 31 (19, 46) | 1,544 | 26 (24, 27) |
| 35–49 | 2,372 | 25 (24, 27) | 34 | 40 (12, 76) | 170 | 22 (13, 36) | 2,168 | 25 (24, 27) |
| 50–64 | 3,337 | 24 (22, 26) | 26 | 5.1 (1.8, 14) | 241 | 37 (23, 53) | 3,070 | 24 (22, 26) |
| 65+ | 2,477 | 25 (23, 26) | 8 | 1.2 (0.40, 3.7) | 72 | 9.8 (4.1, 22) | 2,397 | 25 (23, 27) |
| Race & ethnicity | ||||||||
| Asian | 1,310 | 22 (20, 24) | 3 | 0.4 (0.09, 1.5) | 34 | 14 (6.4, 29) | 1,273 | 22 (20, 24) |
| Black | 480 | 5.6 (4.6, 6.7) | 5 | 4.0 (0.65, 21) | 29 | 11 (3.5, 30) | 446 | 5.5 (4.6, 6.6) |
| Latino/Hispanic | 1,595 | 17 (16, 19) | 25 | 41 (11, 79) | 101 | 27 (15, 43) | 1,469 | 17 (16, 19) |
| White | 5,864 | 50 (48, 52) | 35 | 53 (18, 85) | 348 | 44 (30, 59) | 5,481 | 50 (48, 52) |
| Other/unknown | 576 | 5.0 (4.2, 6.0) | 9 | 1.4 (0.47, 4.0) | 57 | 3.5 (1.9, 6.4) | 510 | 5.1 (4.2, 6.0) |
| Sex | ||||||||
| Female | 6,680 | 58 (56, 60) | 60 | 60 (21, 89) | 452 | 75 (57, 86) | 6,168 | 58 (56, 60) |
| Male | 3,145 | 42 (40, 44) | 17 | 40 (11, 79) | 117 | 25 (14, 43) | 3,011 | 42 (40, 44) |
| Body mass index, kg/m 2 | ||||||||
| < 30 | 5,158 | 47 (45, 49) | 27 | 27 (6.3, 67) | 252 | 38 (25, 53) | 4,879 | 48 (46, 50) |
| ≥ 30 | 3,367 | 26 (24, 28) | 42 | 40 (11, 79) | 272 | 45 (31, 60) | 3,053 | 26 (24, 27) |
| Charlson Comorbidity Index score | ||||||||
| 0 or no visits | 5,754 | 69 (67, 70) | 43 | 91 (74, 97) | 301 | 56 (41, 70) | 5,410 | 69 (67, 71) |
| 1–2 | 2,868 | 21 (20, 23) | 26 | 7.7 (2.1, 24) | 188 | 27 (16, 43) | 2,654 | 21 (20, 23) |
| 3+ | 1,203 | 10 (9.1, 11) | 8 | 1.4 (0.48, 4.2) | 80 | 17 (8.0, 32) | 1,115 | 10 (9.0, 11) |
| Atherosclerotic cardiovascular disease (ASCVD) | 1,739 | 14 (13, 15) | 7 | 1.1 (0.36, 3.5) | 100 | 16 (8.2, 29) | 1,632 | 14 (13, 15) |
| Pulmonary disease | 2,042 | 14 (12, 15) | 21 | 4.4 (1.6, 11) | 157 | 33 (20, 49) | 1,864 | 13 (12, 15) |
| Rheumatologic disease | 251 | 1.0 (0.72, 1.5) | 6 | 1.4 (0.40, 4.7) | 25 | 0.9 (0.34, 2.3) | 220 | 1.0 (0.71, 1.5) |
| Diabetes | 1,223 | 12 (11, 14) | 10 | 7.1 (1.4, 30) | 81 | 20 (9.8, 38) | 1,132 | 12 (11, 13) |
| Renal disease | 583 | 6.4 (5.5, 7.5) | 3 | 0.5 (0.12, 2.2) | 33 | 10 (3.4, 26) | 547 | 6.4 (5.4, 7.4) |
| Cancer | 430 | 3.8 (3.1, 4.6) | 1 | 0.1 (0.01, 1.0) | 22 | 0.7 (0.27, 1.9) | 407 | 3.8 (3.2, 4.7) |
| COVID-19 vaccination status at time of survey | ||||||||
| None | 711 | 5.4 (4.6, 6.4) | 12 | 24 (4.8, 66) | 64 | 5.3 (2.5, 11) | 635 | 5.4 (4.5, 6.3) |
| Primary series only | 1,266 | 12 (11, 13) | 20 | 9.3 (2.8, 26) | 83 | 16 (8.6, 28) | 1,163 | 12 (11, 13) |
| Primary and at least one additional dose | 7,666 | 81 (79, 82) | 41 | 66 (29, 90) | 411 | 78 (66, 87) | 7,214 | 81 (79, 82) |
| Other | 182 | 1.8 (1.3, 2.4) | 4 | 0.7 (0.17, 2.7) | 11 | 0.5 (0.13, 1.9) | 167 | 1.8 (1.3, 2.5) |
| COVID-19 vaccination status at first COVID-19 episode | ||||||||
| None | 1,916 | 21 (19, 23) | 53 | 96 (87, 99) | 117 | 22 (14, 34) | 1,746 | 21 (19, 22) |
| Primary series only | 1,421 | 18 (16, 20) | 18 | 3.7 (1.1, 11) | 69 | 40 (22, 60) | 1,334 | 18 (16, 20) |
| Primary and at least one additional dose | 2,323 | 53 (51, 56) | 4 | 0.5 (0.14, 1.8) | 106 | 36 (19, 58) | 2,213 | 54 (51, 57) |
| Other | 340 | 7.7 (6.3, 9.4) | 2 | 0.3 (0.05, 1.3) | 25 | 2.4 (0.90, 6.2) | 313 | 7.8 (6.4, 9.6) |
EHR = electronic health record; ASCVD = Atherosclerotic cardiovascular disease; CI = 95% confidence interval
aIncludes all people without ME/CFS-like illness regardless of whether they have had COVID-19
bThe estimates presented depend on the variable type. The “Respondents” variable presents the unweighted n and unweighted percent. The “Estimated population size” variable presents the weighted n (CI) and weighted percent (CI). Categorical variables present the unweighted n and weighted percent (CI). Continuous variables present the weighted mean (CI)
cMeeting the ME/CFS diagnostic criteria is defined as having the following symptoms frequently, at a moderate to severe intensity, for at least six months: fatigue, post-exertional malaise, and unrefreshing sleep or sleep problems, as well as one or both of cognitive impairment or orthostatic intolerance. In addition, the fatigue must substantially limit one’s ability to pursue work, educational, social, or recreational activities, and rest must not make the fatigue substantially better (e.g. not answering “Yes, a lot” to the question “Does rest make fatigue better?”)
dFrequent, moderate to severe, lasting ≥ 6 months