Table 2.
Newborn and blood spot sample characteristics by case and control status
| Early-onset (0–6 days) cases: n (col %) |
Late-onset (7–89 days) cases: n (col %) |
All cases n (col %) |
Controls n (col %) |
|
|---|---|---|---|---|
| Total | 268 (100) | 375 (100) | 643 (100) | 2801 (100) |
| Newborn characteristics | ||||
| Gestational age (weeks) | ||||
| <34 | 54 (20) | 127 (34) | 181 (28) | 100 (4) |
| 34–36 | 20 (7) | 50 (13) | 70 (11) | 244 (9) |
| ≥37 | 193 (72) | 197 (53) | 390 (61) | 2449 (87) |
| Missing | 1 (< 1) | 1 (< 1) | 2 (< 1) | 8 (< 1) |
| Birth weight in grams, | ||||
| Median (min–max) | 3150 (455–4740) | 2610 (360–4770) | 2853 (360–4770) | 3220 (445–6650) |
| Missing n (%) | 0 (0) | 14 (4) | 14 (2) | 30 (1) |
| Duration of birth hospitalization (days) | ||||
| Median (min–max) | 11 (< 1–141) | 4 (< 1–214) | 10 (0–214) | 2 (0–348) |
| Missing n (%) | 11 (4) | 26 (7) | 37 (6) | 41 (1) |
| Receipt of antibiotics during birth hospitalizationa | N = 117 | N = 125 | N = 242 | N = 2799 |
| Yes | 99 (85) | 57 (46) | 156 (64) | 383 (14) |
| No | 9 (8) | 54 (43) | 63 (26) | 2399 (86) |
| Missing | 9 (8) | 14 (11) | 23 (10) | 17 (< 1) |
| Race and ethnicity | ||||
| Hispanic or Latino | 32 (12) | 53 (14) | 85 (13) | 497 (18) |
| Non-Hispanic (NH) Black | 102 (38) | 138 (37) | 240 (37) | 1136 (41) |
| NH Asian or Pacific Islander | 15 (6) | 28 (7) | 43 (7) | 418 (15) |
| NH American Indian or Alaska Native | 0 | 0 | 0 | 2 (< 1) |
| NH White | 102 (38) | 146 (39) | 248 (39) | 649 (23) |
| Missing | 17 (6) | 10 (3) | 27 (4) | 99 (4) |
| Sex | ||||
| Male | 139 (52) | 189 (50) | 328 (51) | 1427 (51) |
| Female | 127 (47) | 182 (49) | 309 (48) | 1373 (49) |
| Missing | 2 (< 1) | 4 (1) | 6 (< 1) | 1 (< 1) |
| Year of birth | ||||
| 2010–2012 | 13 (5) | 18 (5) | 31 (5) | 0 (0) |
| 2013–2017 | 84 (31) | 139 (37) | 223 (35) | 0 (0) |
| 2018–2022b | 171 (64) | 218 (58) | 389 (60) | 2801 (100) |
| Age at GBS illness onset (cases only) | – | |||
| Median (days) (IQR) | 0 (0–0) | 31 (18–49) | 13 (0–36) | – |
| Syndrome (cases only) | – | |||
| Bacteremia without focus | 212 (79) | 199 (53) | 411 (64) | – |
| Meningitis | 34 (13) | 140 (37) | 174 (27) | – |
| Otherc | 22 (8) | 36 (10) | 58 (9) | – |
| Outcome of GBS illness (cases only) | – | |||
| Survived | 251 (94) | 347 (93) | 598 (93) | – |
| Died | 16 (6) | 27 (7) | 43 (7) | – |
| Missing | 1 (< 1) | 1 (< 1) | 2 (< 1) | – |
| Blood spot characteristics | ||||
| Age of the baby when DBS was collected | ||||
| Median (days) (IQR) | 1 (0–2) | 1 (1–2) | 1 (1–2) | 1 (1–1) |
| Missing n (%) | 0 (0) | 1 (< 1) | 1 (< 1) | 9 (< 1) |
| Age of baby when DBS was collected | ||||
| <24 hours (0 day)d | 125 (47) | 102 (27) | 227 (35) | 633 (23) |
| 24–<48 hours (1 day) | 73 (27) | 198 (53) | 271 (42) | 1,885 (67) |
| 48–<72 hours (2 days) | 36 (13) | 44 (12) | 80 (12) | 198 (7) |
| 72–<96 hours (3 days) | 12 (4) | 5 (1) | 17 (3) | 13 (< 1) |
| 96 hours or more (4+ days) | 22 (8) | 25 (7) | 47 (7) | 63 (2) |
| Missing | 0 | 1 (< 1) | 1 (< 1) | 9 (< 1) |
| Timing of DBS collection relative to onset of GBS illness (cases only) | ||||
| Before or on the same day as the case–defining culture | 123 (46) | 370 (99) | 493 (77) | – |
| 1–3 days after | 120 (45) | 1 (< 1) | 121 (19) | – |
| >3 days after | 25 (9) | 3 (< 1) | 28 (4) | – |
| Missing | 0 | 1 (< 1) | 1 (< 1) | – |
aCase data limited to 2020–2022; not routinely collected pre-2020.
bEnrollment ended 31 Dec 2022, but six controls were born in early 2023 after their mothers were identified as GBS colonized and enrolled near the end of 2022.
cIncludes other invasive syndromes, the most common of which were cellulitis, septic shock, and bacteremic pneumonia.
dNumber of days used if hours were not available due to missing time of collection or time of birth.