Table 1 Clinical course, diagnostic tests, and treatment of pertussis in term and preterm infants. Denominator is the number of infants in the group, which is noted in column headings or the respective cells
From: Pertussis hospitalizations among term and preterm infants: clinical course and vaccine effectiveness
|  | Total group (n = 676) | Probable and certain term infants (n = 596)a | Certain term infants (n = 388)b | Preterm infants (n = 80) |
|---|---|---|---|---|
Characteristics of hospitalization, clinical course, and treatment | ||||
 Boys; n (%)1 | 335 (49.6%) | 295 (49.5%) | 185 (47.7%) | 40 (50%) |
 Age in months at admittance; median (range) | 2.0 (0–36) | 2.0 (0–35) | 2.0 (0–35) | 3.0 (0–25)c,d |
 Duration of hospitalization in days; median (range) | 5.0 (1–51) | 5.0 (1–51) | 5.0 (1–51) | 6.0 (1–49) |
 Admission intensive care unit (ICU); n (%) | 69 (10.2%) | 59 (9.9%) | 50 (12.9%) | 10 (12.5%) |
 Duration ICU stay in days; median (range) | 9 (2–34) | 9 (2–25) | 9 (2–25) | 15 (8–34)c,d |
 Vaccinated at admission; n (%) | 250/541 (46.2%) | 213/481 (44.3%) | 130/319 (40.7%) | 37/60 (61.7%)c,d |
 Coughing attacks; n (%) | 494 (73.1%) | 438 (73.5%) | 280 (72.2%) | 56 (70.0%) |
 Apnea; n (%) | 110 (16.3%) | 92 (15.4%) | 71 (18.3%) | 18 (22.5%) |
 Whooping; n (%) | 24 (3.6%) | 23 (3.9%) | 18 (4.6%) | 1 (1.3%) |
 Vomiting; n (%) | 238 (35.2%) | 210 (35.2%) | 146 (37.6%) | 28 (35.0%) |
 Prolonged inspiratory effort; n (%) | 49 (7.3%) | 42 (7.1%) | 33 (8.5%) | 7 (8.8%) |
 Collapse; n (%) | 8 (1.2%) | 6 (1.0%) | 5 (1.3%) | 2 (2.5%) |
 Cyanosis; n (%) | 284 (42.0%) | 259 (43.5%) | 176 (45.4%) | 25 (31.3%)c,d |
 Fever; n (%) | 60 (8.9%) | 52 (8.7%) | 33 (8.5%) | 8 (10.0%) |
 Feeding problems; n (%) | 212 (31.4%) | 185 (31.0%) | 133 (34.3%) | 27 (33.8%) |
 Any complicatione; n (%) | 63 (9.3%) | 53 (8.9%) | 39 (10.1%) | 10 (12.5%) |
 Antibiotics before admissionf; n (%) | 131/657 (19.9%) | 114/580 (19.7%) | 66/377 (17.5%) | 18/77 (23.4%) |
 Antibiotics during admissiong; n (%) | 543/674 (80.5%) | 475/587 (80.9%) | 313/382 (81.9%) | 68/78 (87.2%) |
 Intravenous antibiotics during admission; n (%) | 12/403 (3.0%) | 9/357 (2.5%) | 6/244 (2.5%) | 3/46 (6.5%) |
 Antibiotic use in days; median (range) | 6 (0–28) | 6 (0–28) | 5 (0–28) | 5.5 (1–18) |
 Artificial respiration; n (%) | 50/654 (7.7%) | 39/577 (6.8%) | 32/375 (8.5%) | 11/77 (14.3%)c |
 Additional oxygen; n (%) | 226/661 (34.2%) | 198/585 (33.9%) | 150/382 (39.3%) | 28 (36.8%) |
 Symptoms remaining; n (%) | 518 (76.6%) | 460 (77.2%) | 298 (76.8%) | 58 (72.5%) |
 Re-admittance <6w after discharge; n (%) | 94 (14.0%) | 85 (14.3%) | 56 (14.4%) | 9 (11.4%) |
Diagnostics | ||||
 Pertussis test: culture, PCR and serology; n (%) | 34 (5.0%) | 31 (5.2%) | 24 (6.2%) | 3 (3.8%) |
 Pertussis test: culture and PCR; n (%) | 59 (8.7%) | 52 (8.7%) | 40 (10.3%) | 7 (8.8%) |
 Pertussis test: PCR and serology; n (%) | 84 (12.4%) | 73 (12.2%) | 41 (10.6%) | 11 (13.8%) |
 Pertussis test: culture and serology; n (%) | 24 (3.6%) | 24 (4.0%) | 17 (4.4%) | 0 (0%) |
 Pertussis test: culture; n (%) | 37 (5.5%) | 29 (4.9%) | 18 (4.6%) | 8 (10%) |
 Pertussis test: PCR; n (%) | 329 (48.7%) | 290 (48.7%) | 194 (50%) | 39 (48.8%) |
 Pertussis test: serology; n (%) | 69 (10.2%) | 61 (10.2%) | 36 (9.3%) | 8 (10%) |
 Unknown diagnostic test for pertussis; n (%) | 40 (5.9%) | 36 (6.0%) | 18 (4.6%) | 4 (5%) |
 Result white blood cell counting; n (%) | 225/476 (47.3%) | 200/421 (47%) | 141/276 (51.1%) | 25/55 (45%) |
 White blood cell count; median (range) | 17.2 (4.3–106.1) | 17.7 (5.3–106.1) | 17.2 (5.3–74.3) | 13.5 (4.3–64.0) |
 Result C-reactive protein; n (%) | 142/392 (36.2%) | 119/344 (35%) | 81/231 (35.1%) | 23/48 (48%) |
 C-reactive protein; median (range) | 5 (0–415) | 4.7 (0–415) | 5 (0–415) | 15 (0–363)c,d |
 Positive co-infectionsh; n (%) | 81/355 (22.8%) | 63/306 (20.6%) | 46/208 (22.1%) | 18/49 (36.7%)c,d |
Specification of prescribed antibiotics before admission | ||||
 Amoxicillin | 49/132 (37%) | 38/114 (33%) | 23/66 (35%) | 11/18 (65%) |
 Azithromycin | 24/132 (18%) | 21/114 (18%) | 17/66 (26%) | 3/18 (18%) |
 Ceftriaxone | 1/132 (1%) | 1/114 (1%) | 1/66 (2%) | 0/0 |
 Clarithromycin | 41/132 (31%) | 38/114 (33%) | 17/66 (26%) | 3/18 (18%) |
 Erythromycin | 7/132 (5%) | 6/114 (5%) | 2/66 (3%) | 1/18 (6%) |
 Feneticillin | 1/132 (1%) | 1/114 (1%) | 1/66 (2%) | 0/0 |
 Trimethoprim | 1/132 (1%) | 1/114 (1%) | 1/66 (2%) | 0/0 |
 unknown | 7/132 (5%) | 8/114 (7%) | 4/66 (6%) | 0/18 (0%) |
Specification of prescribed antibiotics during admission | ||||
 Amoxicillin | 11/543 (2%) | 10/475 (2%) | 7/313 (2%) | 1/68 (1%) |
 Azithromycin | 170/543 (31%) | 146/475 (31%) | 98/313 (31%) | 24/68 (35%) |
 Cephotaxim | 1/543 (0.2%) | 0/0 | 0/0 | 1/68 (1%) |
 Clarithromycin | 314/543 (58%) | 280/475 (59%) | 184/313 (59%) | 34/68 (50%) |
 Erythromycin | 44/543 (8%) | 37/475 (8%) | 23/313 (7%) | 7/68 (10%) |
 unknown | 3/543 (0.6%) | 2/475 (0.4%) | 1/313 (0.3%) | 1/68 (1%) |
Specification of reported complications | ||||
 conjunctivitis | 5 (0.7%) | 5 (0.8%) | 1 (0.3%) | 0 (0%) |
 convulsion | 5 (0.7%) | 5 (0.8%) | 4 (1.0%) | 0 (0%) |
 encephalopathy | 1 (0.2%) | 1 (0.2%) | 1 (0.3%) | 0 (0%) |
 pneumonia | 11 (1.6%) | 9 (1.5%) | 7 (1.8%) | 2 (2.5%) |
 otitis media | 1 (0.2%) | 1 (0.2%) | 0 (0%) | 0 (0%) |
 death | 2 (0.3%) | 2 (0.3%) | 2 (0.5%) | 0 (0%) |
 bradycardia | 8 (1.2%) | 7 (1.2%) | 6 (1.6%) | 1 (1.3%) |
 cardio-respiratory insufficiency | 7 (1.0%) | 5 (0.8%) | 4 (1.0%) | 2 (2.5%) |
 desaturation | 20 (3.0%) | 18 (3.0%) | 14 (3.6%) | 2 (2.5%) |
 feeding problems | 5 (0.7%) | 2 (0.3%) | 0 (0%) | 3 (3.8%) |
 weight loss | 12 (1.8%) | 11 (1.9%) | 8 (2.1%) | 1 (1.3%) |
 dehydration | 1 (0.2%) | 1 (0.2%) | 1 (0.3%) | 0 (0%) |
 need for drip-feed | 4 (0.6%) | 2 (0.3%) | 1 (0.3%) | 2 (2.5%) |
 gastroenteritis | 3 (0.4%) | 2 (0.3%) | 2 (0.5%) | 1 (1.3%) |
 sepsis | 1 (0.2%) | 1 (0.2%) | 0 (0%) | 0 (0%) |
 extreme high white blood cell count | 2 (0.3%) | 1 (0.2%) | 0 (0%) | 1 (1.3%) |
 metabolic alkalosis | 1 (0.2%) | 1 (0.2%) | 0 (0%) | 0 (0%) |
 hypotonia | 2 (0.3%) | 1 (0.2%) | 1 (0.3%) | 1 (1.3%) |