Table 2 Clinical manifestations associated with AH1N1 influenza infection in individuals who received medical care in San Luis Potosi State from March to October 2009
Clinical characteristics | Confirmed AH1N1 infection, n (%) | Crude OR [95% CI] | ||
|---|---|---|---|---|
Positive (n = 2767) | Negative (n = 3391) | |||
Signs | Fever | 2665 (96.3) | 2927 (86.3) | 4.14 [3.32–5.16] |
Cough | 2610 (94.3) | 2825 (83.3) | 3.33 [2.76–4.00] | |
Clear rhinorrhea | 2071 (74.8) | 2077 (61.3) | 1.88 [1.68–2.10] | |
Nasal congestion | 1376 (49.7) | 1361 (40.1) | 1.47 [1.33–1.63] | |
Sore throat | 1498 (54.1) | 1547 (45.6) | 1.40 [1.27–1.55] | |
Conjunctivitis | 728 (26.3) | 702 (20.7) | 1.36 [1.21–1.54] | |
Dysphonia | 476 (17.2) | 505 (14.9) | 1.18 [1.03–1.36] | |
Tachypnea | 107 (3.9) | 209 (6.2) | 0.61 [0.48–0.77] | |
Cyanosis | 28 (1.0) | 57 (1.7) | 0.59 [0.37–0.94] | |
Purulent rhinorrhea | 57 (2.1) | 122 (3.6) | 0.56 [0.41–0.77] | |
Leukocytosis | 3 (0.1) | 28 (0.8) | 0.13 [0.04–0.42] | |
Symptoms | Headache | 2591 (93.6) | 2785 (82.1) | 3.20 [2.68–3.82] |
Malaise | 2087 (75.4) | 2252 (66.4) | 1.55 [1.38–1.76] | |
Chills | 1356 (49.0) | 1423 (42.0) | 1.32 [1.20–1.47] | |
Myalgia | 1775 (64.1) | 1977 (58.3) | 1.28 [1.15–1.41] | |
Irritability | 262 (9.5) | 267 (7.9) | 1.22 [1.02–1.46] | |
Arthralgia | 1570 (56.7) | 1785 (52.6) | 1.18 [1.06–1.30] | |
Thoracic pain | 449 (16.2) | 548 (16.2) | 1.00 [0.87–1.15] | |
Dyspnea | 218 (7.9) | 439 (12.9) | 0.57 [0.48–0.68] | |
Risk factors | Contact with infected (flu) | 433 (15.6) | 374 (11.0) | 1.49 [1.29–1.73] |
Antiviral treatment1 | 47 (1.7) | 48 (1.4) | 1.20 [0.80–1.80] | |
Seasonal flu vaccine | 258 (9.3) | 343 (10.1) | 0.91 [0.77–1.08] | |
Asthma/COPD | 36 (1.3) | 45 (1.3) | 0.98 [0.63–1.52] | |
|  | Smoking | 44 (1.6) | 62 (1.8) | 0.86 [0.58–1.28] |