Background
Methods
Characteristics at/prior to PCR testing | Total population (N=7139) | SARS-CoV-2 negative (N=3893) | SARS-CoV-2 positive (N=3246) | |||
---|---|---|---|---|---|---|
N | % | N | % | N | % | |
Sex | ||||||
Male | 2646 | 37.06 | 1444 | 37.09 | 1202 | 37.03 |
Female | 4493 | 62.94 | 2449 | 62.91 | 2044 | 62.97 |
Age (years) | ||||||
11–13 | 2212 | 30.98 | 1255 | 32.24 | 957 | 29.47 |
14–15 | 1883 | 26.38 | 997 | 25.61 | 886 | 27.30 |
16–17 | 3044 | 42.64 | 1641 | 42.15 | 1404 | 43.22 |
Index of Multiple Deprivation | ||||||
Quintile 1 (most deprived) | 1471 | 20.61 | 785 | 20.16 | 686 | 21.13 |
Quintile 2 | 1422 | 19.92 | 761 | 19.55 | 661 | 20.36 |
Quintile 3 | 1367 | 19.15 | 764 | 19.62 | 603 | 18.58 |
Quintile 4 | 1377 | 19.29 | 752 | 19.32 | 625 | 19.25 |
Quintile 5 (least deprived) | 1502 | 21.04 | 831 | 21.35 | 671 | 20.67 |
Ethnicity | ||||||
White | 5279 | 73.95 | 2908 | 74.70 | 2371 | 73.04 |
Asian/Asian British | 1064 | 14.90 | 550 | 14.13 | 514 | 15.83 |
Black/African/Caribbean | 267 | 3.74 | 151 | 3.88 | 116 | 3.57 |
Mixed | 358 | 45.01 | 203 | 5.21 | 155 | 4.78 |
Others | 118 | 1.65 | 55 | 1.41 | 63 | 1.94 |
Preferred not to say | 53 | 0.74 | 26 | 0.67 | 27 | 0.83 |
Self-rated physical health | ||||||
Very good | 2443 | 34.22 | 1326 | 34.06 | 1117 | 34.41 |
Good | 3017 | 42.26 | 1653 | 42.46 | 1364 | 42.02 |
Okay | 1526 | 21.38 | 828 | 21.27 | 698 | 21.50 |
Poor/very poor | 153 | 2.14 | 86 | 2.21 | 67 | 2.06 |
Self-rated mental health | ||||||
Very good | 1789 | 25.06 | 960 | 24.66 | 829 | 25.54 |
Good | 2634 | 36.90 | 1453 | 37.32 | 1181 | 36.38 |
Okay | 2053 | 28.76 | 1109 | 28.49 | 944 | 29.08 |
Poor/very poor | 663 | 9.29 | 371 | 9.53 | 292 | 9.00 |
Lonelinessa | ||||||
Never | 2079 | 29.12 | 1113 | 28.59 | 966 | 29.76 |
Hardly ever | 2092 | 29.30 | 1119 | 28.74 | 973 | 29.98 |
Occasionally | 1249 | 17.50 | 696 | 17.88 | 553 | 17.04 |
Some of the time | 1229 | 17.22 | 675 | 17.34 | 554 | 17.07 |
Often/always | 490 | 6.86 | 290 | 7.45 | 200 | 6.16 |
Number of symptoms at testing | ||||||
0 | 5673 | 79.46 | 3564 | 91.55 | 2109 | 64.97 |
1–4 | 556 | 7.79 | 178 | 4.58 | 378 | 11.65 |
5+ | 910 | 12.75 | 151 | 3.88 | 759 | 23.38 |
Mobilityb | ||||||
No problems | 6800 | 95.25 | 3694 | 94.89 | 3106 | 95.69 |
Some/a lot of problems | 339 | 4.75 | 199 | 5.11 | 140 | 4.31 |
Looking after selfb | ||||||
No problems | 6837 | 95.77 | 3714 | 95.40 | 3123 | 96.21 |
Some/a lot of problems | 302 | 4.23 | 179 | 4.60 | 123 | 3.79 |
Doing usual activitiesb | ||||||
No problems | 6382 | 89.40 | 3487 | 89.57 | 2895 | 89.19 |
Some/a lot of problems | 757 | 10.60 | 406 | 10.43 | 351 | 10.81 |
Having painb | ||||||
No problems | 6118 | 85.70 | 3342 | 85.85 | 2776 | 85.52 |
Some/a lot of problems | 1021 | 14.30 | 551 | 14.15 | 470 | 14.48 |
Feeling worried/sadb | ||||||
No problems | 4261 | 59.69 | 2331 | 59.88 | 1930 | 59.46 |
A bit | 2421 | 33.91 | 1291 | 33.16 | 1130 | 34.81 |
Very worried/sad | 457 | 6.40 | 271 | 6.96 | 186 | 5.73 |
Outcome: long COVID (experiencing at least one impairing symptom)
Characteristics 3 months after a PCR test | Total population (N=7139) | SARS-CoV-2 negative (N=3893) | SARS-CoV-2 positive (N=3246) | |||
---|---|---|---|---|---|---|
N | % | N | % | N | % | |
Outcome | ||||||
Long COVID at 3 months | ||||||
No | 5603 | 78.48 | 3174 | 81.53 | 2429 | 74.83 |
Yes | 1536 | 21.52 | 719 | 18.47 | 817 | 25.17 |
Variables related to the outcomea | ||||||
Number of symptoms | ||||||
0 | 2968 | 41.57 | 1848 | 47.47 | 1120 | 34.50 |
1–4 | 3496 | 48.97 | 1798 | 46.19 | 1698 | 52.31 |
5+ | 675 | 9.46 | 247 | 6.34 | 428 | 13.19 |
Mobility | ||||||
No problems | 6683 | 93.61 | 3680 | 94.53 | 3003 | 92.51 |
Some/a lot of problems | 456 | 6.39 | 213 | 5.47 | 243 | 7.49 |
Looking after self | ||||||
No problems | 6819 | 95.52 | 3709 | 95.27 | 3110 | 95.81 |
Some/a lot of problems | 320 | 4.48 | 184 | 4.73 | 136 | 4.19 |
Doing usual activities | ||||||
No problems | 6099 | 85.43 | 3376 | 86.72 | 2723 | 83.89 |
Some/a lot of problems | 1040 | 14.57 | 517 | 13.28 | 523 | 16.11 |
Having pain | ||||||
No problems | 6016 | 84.27 | 3327 | 85.46 | 2689 | 82.84 |
Some/a lot of problems | 1123 | 15.73 | 566 | 14.54 | 557 | 17.16 |
Feeling worried/sad | ||||||
No problems/a bit | 6571 | 92.04 | 3581 | 91.99 | 2990 | 92.11 |
Very worried/sad | 568 | 7.96 | 312 | 8.01 | 256 | 7.89 |
Potential predictors
Sample size and missing data
Statistical analysis
Results
Univariable associations
Potential predictor | Total population (N=7139) | SARS-CoV-2 negative (N=3893) | SARS-CoV-2 positive (N=3246) | Pinteractiona | |||
---|---|---|---|---|---|---|---|
Odds ratio (95% CIs) | p value | Odds ratio (95% CIs) | p value | Odds ratio (95% CIs) | p value | ||
SARS-CoV-2 status | |||||||
Negative | Ref | <0.001 | |||||
Positive | 1.48 (1.33, 1.66) | N/A | N/A | N/A | |||
Sex | |||||||
Male | Ref | <0.001 | Ref | <0.001 | Ref | <0.001 | 0.5858 |
Female | 2.02 (1.78, 2.30) | 2.11 (1.75, 2.54) | 1.96 (1.65, 2.34) | ||||
Age (years)b | |||||||
11–13 | Ref | <0.001 | Ref | <0.001 | Ref | <0.001 | 0.2533 |
14–15 | 1.54 (1.32, 1.80) | 1.71 (1.37, 2.13) | 1.36 (1.09, 1.70) | ||||
16–17 | 1.73 (1.50, 1.99) | 1.73 (1.42, 2.12) | 1.70 (1.40, 2.07) | ||||
Index of Multiple Deprivation | |||||||
Quintile 1 (most deprived) | Ref | <0.001 | Ref | 0.034 | Ref | 0.004 | 0.149 |
Quintile 2 | 0.99 (0.83, 1.17) | 0.82 (0.64, 1.05) | 1.18 (0.93, 1.49) | ||||
Quintile 3 | 0.88 (0.74, 1.05) | 0.79 (0.62, 1.02) | 1.00 (0.78, 1.28) | ||||
Quintile 4 | 0.79 (0.66, 0.94) | 0.69 (0.53, 0.89) | 0.90 (0.70, 1.16) | ||||
Quintile 5 (least deprived) | 0.72 (0.60, 0.86) | 0.72 (0.56, 0.93) | 0.72 (0.56, 0.93) | ||||
Ethnicity | |||||||
White | Ref | 0.055 | Ref | 0.146 | Ref | 0.131 | 0.417 |
Asian/Asian British | 0.93 (0.79, 1.09) | 0.93 (0.73, 1.18) | 0.90 (0.72, 1.13) | ||||
Black/African/Caribbean | 1.11 (0.83, 1.48) | 1.36 (0.92, 2.01) | 0.89 (0.57, 1.38) | ||||
Mixed | 1.38 (1.09, 1.76) | 1.43 (1.03, 2.00) | 1.36 (0.95, 1.93) | ||||
Others | 0.70 (0.43, 1.16) | 1.00 (0.50, 2.00) | 0.49 (0.24, 1.00) | ||||
Preferred not to say | 0.96 (0.49, 1.87) | 0.59 (0.18, 1.97) | 1.23 (0.54, 2.83) | ||||
Self-rated physical health | |||||||
Very good | Ref | <0.001 | Ref | <0.001 | Ref | <0.001 | <0.001 |
Good | 2.06 (1.77, 2.39) | 2.49 (1.98, 3.13) | 1.80 (1.47, 2.20) | ||||
Okay | 3.57 (3.04, 4.20) | 4.51 (3.54, 5.76) | 3.00 (2.40, 3.74) | ||||
Poor/very poor | 7.60 (5.41, 10.68) | 14.91 (9.32, 23.85) | 3.71 (2.23, 6.19) | ||||
Self-rated mental health | |||||||
Very good | Ref | <0.001 | Ref | <0.001 | Ref | <0.001 | 0.015 |
Good | 2.12 (1.75, 2.56) | 2.55 (1.87, 3.81) | 1.92 (1.50, 2.46) | ||||
Okay | 3.91 (3.23, 4.73) | 5.50 (4.06, 7.46) | 3.06 (2.39, 3.93) | ||||
Poor/very poor | 12.72 (10.17, 15,91) | 17.46 (12.43, 24.53) | 10.54 (7.72, 14.40) | ||||
Lonelinessc | |||||||
Never | Ref | <0.001 | Ref | <0.001 | Ref | <0.001 | 0.002 |
Hardly ever | 1.75 (1.45, 2.11) | 2.16 (1.59, 2.93) | 1.54 (1.21, 1.96) | ||||
Occasionally | 3.91 (3.23, 4.73) | 5.28 (3.91, 7.14) | 3.30 (2.56, 4.26) | ||||
Some of the time | 4.81 (3.98, 5.80) | 6.86 (5.10, 9.22) | 3.82 (2.97, 4.91) | ||||
Often/always | 7.98 (6.34, 10.04) | 13.41 (9.56, 18.80) | 5.23 (3.75, 7.30) | ||||
Number of symptoms at testingb | |||||||
0 | Ref | <0.001 | Ref | <0.001 | Ref | <0.001 | 0.148 |
1–4 | 0.43 (0.32, 0.57) | 0.41 (0.24, 0.70) | 0.37 (0.26, 0.52) | ||||
5+ | 1.88 (1.62, 2.19) | 2.20 (1.55, 3.12) | 1.49 (1.24, 1.79) | ||||
Mobilityd | |||||||
No problems | Ref | <0.001 | Ref | <0.001 | Ref | <0.001 | 0.024 |
Some/a lot of problems | 6.81 (5.42, 8.55) | 8.82 (6.53, 11.91) | 5.17 (3.65, 7.34) | ||||
Looking after selfd | |||||||
No problems | Ref | <0.001 | Ref | <0.001 | Ref | <0.001 | 0.205 |
Some/a lot of problems | 8.89 (6.92, 11.40) | 10.58 (7.65, 14.62) | 7.61 (5.13, 11.28) | ||||
Doing usual activitiesd | |||||||
No problems | Ref | <0.001 | Ref | <0.001 | Ref | <0.001 | < 0.001 |
Some/a lot of problems | 6.52 (5.57, 7.64) | 10.31 (8.26, 12.88) | 4.04 (3.22, 5.08) | ||||
Having paind | |||||||
No problems | Ref | <0.001 | Ref | <0.001 | Ref | <0.001 | <0.001 |
Some/a lot of problems | 9.84 (8.51, 11.38) | 14.66 (11.94, 18.00) | 6.65 (5.40, 8.18) | ||||
Feeling worried/sadd | |||||||
No problems | Ref | <0.001 | Ref | <0.001 | Ref | <0.001 | 0.006 |
A bit | 4.05 (3.56, 4.60) | 5.11 (4.21, 6.21) | 3.35 (2.81, 3.99) | ||||
Very worried/sad | 15.12 (12.20, 18.75) | 17.54 (13.17, 23.36) | 15.38 (10.90, 21.70) |
Multivariable predictive model
Model performance
Worked examples
Characteristic | Examples | |||||
---|---|---|---|---|---|---|
1 | 2 | 3 | 4 | 5 | 6 | |
SARS-CoV-2 status | Positive | Negative | Positive | Negative | Positive | Negative |
Sex | Female | Female | Male | Male | Female | Female |
Age (years) | 17 | 17 | 13 | 13 | 17 | 17 |
Ethnicity | White | White | White | White | White | White |
Self-rated physical health | Okay | Okay | Okay | Okay | Good | Good |
Self-rated mental health | Okay | Okay | Okay | Okay | Good | Good |
Loneliness | Some of the time | Some of the time | Some of the time | Some of the time | Hardly ever | Hardly ever |
Number of symptoms at time of testing | 0 | 0 | 0 | 0 | 3 | 3 |
Problems looking after myself | No problems | No problems | No problems | No problems | No problems | No problems |
Problems doing usual activities | No problems | No problems | No problems | No problems | No problems | No problems |
Having pain | No problems | No problems | No problems | No problems | No problems | No problems |
Feeling worried/sad | A bit worried | A bit worried | A bit worried | A bit worried | No problems | No problems |
Predicted risk of long COVID | 0.342 | 0.217 | 0.241 | 0.189 | 0.076 | 0.030 |