Table 4. Predictive values of presenting symptoms of COVID-19 in the First Few X study in the United Kingdom of Great Britain and Northern Ireland, 31 January to 9 April 2020.
| Symptom, by category | No. of COVID-19 cases with symptom/ total with symptom | No. of non-COVID-19 cases without symptom/ total without symptom | Positive predictive value, % (95% CI) | Negative predictive value, % (95% CI) |
|---|---|---|---|---|
| Fever | ||||
| All cases | 226/462 | 418/545 | 48.9 (44.3–53.6) | 76.7 (72.9–80.2) |
| Imported cases | 108/344 | 418/487 | 31.4 (26.5–36.6) | 85.8 (82.4–88.8) |
| Sporadic cases | 72/308 | 418/432 | 23.4 (18.8–28.5) | 96.8 (94.6–98.2) |
| Secondary cases | 46/282 | 418/462 | 16.3 (12.2–21.2) | 90.5 (87.4–93.0) |
| Age < 30 years | 30/143 | 166/188 | 21.0 (14.6–28.6) | 88.3 (82.8–92.5) |
| Age 30–59 years | 135/207 | 155/240 | 65.2 (58.3–71.7) | 64.6 (58.2–70.6) |
| Age ≥ 60 years | 61/67 | 35/55 | 91.0 (81.5–96.6) | 63.6 (49.6–76.2) |
| Cough | ||||
| All cases | 296/917 | 114/190 | 32.3 (29.3–35.4) | 60.0 (52.7–67.0) |
| Imported cases | 149/770 | 114/158 | 19.4 (16.6–22.3) | 72.2 (64.5–79.0) |
| Sporadic cases | 75/696 | 114/125 | 10.8 (8.6–13.3) | 91.2 (84.8–95.5) |
| Secondary cases | 72/693 | 114/135 | 10.4 (8.2–12.9) | 84.4 (77.2–90.1) |
| Age < 30 years | 44/285 | 62/76 | 15.4 (11.4–20.2) | 81.6 (71.0–89.5) |
| Age 30–59 years | 183/420 | 27/77 | 43.6 (38.8–48.5) | 35.1 (24.5–46.8) |
| Age ≥ 60 years | 69/110 | 6/18 | 62.7 (53.0–71.8) | 33.3 (13.3–59.0) |
| Shortness of breath | ||||
| All cases | 154/316 | 500/712 | 48.7 (43.1–54.4) | 70.2 (66.7–73.6) |
| Imported cases | 54/216 | 500/637 | 25.0 (19.4–31.3) | 78.5 (75.1–81.6) |
| Sporadic cases | 59/221 | 500/528 | 26.7 (21.0–33.0) | 94.7 (92.4–96.4) |
| Secondary cases | 41/203 | 500/547 | 20.2 (14.9–26.4) | 91.4 (88.7–93.6) |
| Age < 30 years | 20/73 | 224/261 | 27.4 (17.6–39.1) | 85.8 (81.0–89.8) |
| Age 30–59 years | 91/150 | 176/315 | 60.7 (52.4–68.5) | 55.9 (50.2–61.4) |
| Age ≥ 60 years | 43/56 | 32/68 | 76.8 (63.6–87.0) | 47.1 (34.8–59.6) |
| Sore throat | ||||
| All cases | 147/493 | 297/497 | 29.8 (25.8–34.1) | 59.8 (55.3–64.1) |
| Imported cases | 78/424 | 297/405 | 18.4 (14.8–22.4) | 73.3 (68.7–77.6) |
| Sporadic cases | 28/374 | 297/343 | 7.49 (5.0–10.6) | 86.6 (82.5–90.0) |
| Secondary cases | 41/387 | 297/343 | 10.6 (7.7–14.1) | 86.6 (82.5–90.0) |
| Age < 30 years | 27/179 | 117/146 | 15.1 (10.2–21.2) | 80.1 (72.2–86.3) |
| Age 30–59 years | 97/216 | 112/239 | 44.9 (38.2–51.8) | 46.9 (40.4–53.4) |
| Age ≥ 60 years | 23/42 | 23/67 | 54.8 (38.7–70.2) | 34.3 (23.2–46.9) |
| Fever and/or cough | ||||
| All cases | 339/1017 | 61/95 | 33.3 (30.4–36.6) | 64.2 (53.7–73.8) |
| Imported cases | 175/853 | 61/79 | 20.5 (17.9–23.4) | 77.2 (66.4–85.9) |
| Sporadic cases | 82/760 | 61/67 | 10.8 (8.7–13.2) | 91.0 (81.5–96.6) |
| Secondary cases | 82/760 | 61/71 | 10.8 (8.7–13.2) | 85.9 (75.6–93.0) |
| Age < 30 years | 54/329 | 31/34 | 16.4 (12.6–20.9) | 91.2 (76.3–98.1) |
| Age 30–59 years | 211/462 | 15/38 | 45.7 (41.1–50.3) | 39.5 (24.0–56.6) |
| Age ≥ 60 years | 74/115 | 6/14 | 64.3 (54.9–73.1) | 42.9 (17.7–71.1) |
| Fever and cough | ||||
| All cases | 183/362 | 573/770 | 50.6 (45.3–55.8) | 74.4 (71.2–77.5) |
| Imported cases | 82/261 | 573/686 | 31.4 (25.8–37.4) | 83.5 (80.5–86.2) |
| Sporadic cases | 65/244 | 573/599 | 26.6 (21.2–32.7) | 95.7 (93.7–97.1) |
| Secondary cases | 36/215 | 573/631 | 16.7 (12.0–22.4) | 90.8 (88.3–92.9) |
| Age < 30 years | 20/99 | 231/270 | 20.2 (12.8–29.5) | 85.6 (80.0–89.5) |
| Age 30–59 years | 107/165 | 210/340 | 64.8 (57.0–72.1) | 61.8 (56.4–67.0) |
| Age ≥ 60 years | 56/62 | 41/69 | 90.3 (80.1–96.4) | 59.4 (46.9–71.1) |
CI: confidence interval; COVID-19: coronavirus disease 2019; NA: not applicable; United Kingdom: United Kingdom of Great Britain and Northern Ireland.
a We collected data on 380 symptomatic COVID-19 cases using the First Few X protocol and 752 contemporaneous confirmed non-COVID-19 respiratory infections. Data are missing in some categories.