Table 1. Demographic Characteristics for 1st-born children versus later-born children who had an ER visit or admission in the first 72 hours following the 2-month vaccination.
| 1st-born Children N = 574 | Later-born Children N = 418 | p-value for difference | |
| Mean (SD) | Mean (SD) | t-test p-value | |
| Maternal Age (years) | 26.6 (6.0) | 29.8 (5.3) | <0.0001 |
| Birth Weight (g) | 3486.8 (396.5) | 3529.9 (455.4) | 0.1074 |
| Gestational Age (Wks) | 39.3 (1.23) | 39.02 (1.15) | 0.0002 |
| N (%) | N (%) | Chi-square test p-value | |
| Low Income (1st or second neighborhood income quintile) | 270 (47.0%) | 204 (48.8%) | 0.5550 |
| Proportion of events that are ER visits | 546 (95.1%) | 391 (93.5%) | 0.3187 |
| CTAS 1,2 or 31 (Denominator is ER visits) | 403 (73.8%) | 281 (71.9%) | 0.5190 |
1
Canadian Triage Acuity Score (CTAS): 1 = Resuscitation, 2 = Emergent, 3 = Urgent, 4 = Less Urgent (Semi urgent), 5 = Non Urgent.