TABLE 1.
Demographic and Clinical Characteristics of Cases and Controls
| All Cases | CXR-positive Cases* | Controls | |
|---|---|---|---|
| All | 525 | 219 | 772 |
| Age | |||
| Median age in months (IQR) | 12 (5, 20) | 12 (6, 21) | 11 (5, 23) |
| 1–5 mo | 136 (25.9) | 50 (22.8) | 221 (28.6) |
| 6–11 mo | 121 (23.0) | 50 (22.8) | 168 (21.8) |
| 12–23 mo | 178 (33.9) | 81 (37.0) | 196 (25.4) |
| 24–59 mo | 90 (17.1) | 38 (17.4) | 187 (24.2) |
| Female | 191 (36.4) | 87 (39.7) | 402 (52.1) |
| Season of enrollment | |||
| Monsoon (June–October) | 270 (51.4) | 119 (54.3) | 320 (41.5) |
| Dry (November–May) | 255 (48.6) | 100 (45.7) | 452 (58.5) |
| Respiratory tract illness† (controls only) | n/a | n/a | 169 (21.9) |
| Number of pentavalent vaccine doses received‡ | |||
| None | 26 (5.0) | 8 (3.7) | 12 (1.6) |
| 1 | 49 (9.4) | 20 (9.2) | 32 (4.2) |
| 2 | 30 (5.7) | 12 (5.5) | 72 (9.4) |
| 3 | 418 (79.9) | 178 (81.7) | 650 (84.9) |
| Pentavalent fully vaccinated for age‡ | |||
| <1-yr old | 214 (83.9) | 85 (85.9) | 346 (88.9) |
| ≥1-yr old | 263 (98.1) | 114 (95.8) | 364 (96.6) |
| ≥1 measles dose received (among children >10.5 mo) | 266 (84.7) | 110 (80.9) | 384 (88.1) |
| Weight-for-age (WHO) Z scores | |||
| >−2 Z scores | 321 (61.1) | 118 (53.9) | 591 (76.6) |
| −3 ≤ Z scores ≤ −2 | 146 (27.8) | 70 (32.0) | 138 (17.9) |
| <−3 Z scores | 58 (11.1) | 31 (14.2) | 43 (5.6) |
| Prematurity (gestational age <37 wk) | 30 (5.9) | 16 (7.4) | 23 (3.0) |
| Prior diagnosis with wheeze or asthma | 100 (19.0) | 56 (25.6) | 49 (6.3) |
| Antibiotic use | |||
| Serum antibiotic activity | 118 (23.9) | 45 (21.6) | 10 (1.4) |
| Parental report of antibiotics | 186 (35.6) | 78 (35.9) | 57 (7.4) |
| Administered at study hospital before specimen collection§ | 41 (7.8) | 21 (9.6) | n/a |
| Evidence of antibiotic exposure before specimen collection¶ | 126 (25.3) | 52 (24.6) | 10 (1.4) |
*CXR-positive cases: presence of alveolar consolidation and/or other infiltrates on chest radiograph.
†Respiratory tract illness defined as (1) cough and/or runny nose or (2) at least 1 of ear discharge, wheezing or difficulty breathing in the presence of either a temperature of ≥38.0°C within past 48 h or a history of sore throat.
‡Numbers reflect children who received pentavalent vaccine (diphtheria-tetanus-pertussis-Haemophilus influenzae type b-hepatitis B vaccine). An additional 32 children, including 6 cases and 26 controls, received diphtheria-tetanus-pertussis-only, not Penta. For children <1 yr, diphtheria-tetanus-pertussis fully vaccinated defined as: received at least 1 dose and up-to-date for age based on the child’s age at enrollment, doses received and country schedule (allowing 4-wk window each for dose). For children >1 yr, defined as 3+ doses.
§Reported by clinician.
¶Presence of antibiotics by serum, antibiotics at the referral hospital, clinician report of antibiotics before blood specimen collection or antibiotics before specimen collection based on time of specimen collection and time of antibiotic administration. Only criterion applicable to controls is serum. Restricted to children with a blood specimen obtained.
IQR indicates interquartile range; n/a, not applicable; WHO, World Health Organization.