Table 1 Clinical data of the 302 patients

Age of onset (day), median (IQR)

78 (22, 353)

Gender (female, n, %)

130 (43.05%)

Hospital length of stay, median (IQR)

7 (1, 32)

Pertussis Toxin IgG antibodies, IU/ml, median (IQR)

2.73 (0.00, 219.76)

WBC count, highest cells×10³/µL, median (IQR)

15.41 (4.44, 93.52)

Lymphocyte count, highest cells×10³/µL, median (IQR)

10.92 (2.22, 43.95)

Raised C-reactive protein (n, %)

16 (5.30%)

Raised Procalcitonin (n, %) > 0.5 ng/ml

10 (3.31%)

Highest respiratory rate (breaths/min)

42 (21, 70)

Highest heart rate (beats/min)

130 (105, 198)

Pneumonia (n, %)

233 (77.15%)

Severe Pneumonia (n, %)

29 (9.60%)

Respiratory failure (n, %)

27 (8.94%)