Table 1. Characteristics of Study Participants According to Group.
| Characteristic | aP Group (n = 221) | Control Group (n = 219) |
|---|---|---|
| Birth weight, mean (range), g | 3479.0 (3417.6-3540.5) |
3548.8 (3492.7-3605.0) |
| Gestation, mean (range), wk | 39.2 (39.0-39.4) | 39.2 (39.0-39.3) |
| Boys, No. (%) | 117 (52.9) | 116 (53.0) |
| aP vaccine days 0-2, No. (%) | 96 (43.4) | NA |
| aP vaccine days 3-5, No. (%) | 124 (56.1) | NA |
| HBV days 0-2, No. (%) | 201 (91.0) | 191/218 (87.6) |
| HBV days 3-5, No. (%) | 20 (9.0) | 27/218 (12.4) |
| Withdrew prior to 2 mo of age, No. (%) | 3 (1.4) | 5 (2.3) |
| Documented maternal Tdap within 5 y prior to enrollment, No. (%) | 49 (22.2) | 47 (21.5) |
Abbreviations: aP, monovalent acellular pertussis vaccine; HBV, hepatitis B vaccine; NA, not applicable; Tdap, tetanus toxoid, reduced diphtheria toxoid, and pertussis antigen content.