Table 1:
Number and proportion of vaccine doses administered by time period, age group and risk group in children aged 12–23 months, and number and proportion of incident events of seizure in the cohort and by risk group
| Categorization | No. (%) of children* | |
|---|---|---|
| MMRV n = 96 686 |
MMR+V n = 181 088 |
|
| Doses administered, by calendar year | ||
| 2006–2009 | NA | 152 985 (84.5) |
| 2010 (MMRV introduced) | 13 689 (14.2) | 27 817 (15.4) |
| 2011–2012 | 82 997 (85.8) | 286 (0.2) |
| Doses administered, by child’s age, mo† | ||
| 12 | 62 782 (64.9) | 123 650 (68.3) |
| 13 | 15 001 (15.5) | 26 273 (14.5) |
| 14 | 7 027 (7.3) | 11 555 (6.4) |
| 15 | 3 603 (3.7) | 6 212 (3.4) |
| 16–17 | 3 607 (3.7) | 5 977 (3.3) |
| 18–23 | 4 666 (4.8) | 7 421 (4.1) |
| Doses administered, by risk level† | ||
| Low risk | 92 570 (95.7) | 174 198 (96.2) |
| High risk‡ | 4 116 (4.3) | 6 890 (3.8) |
| Seizure experienced, total cohort and by risk group, no. (no. per 10 000 doses) | ||
| Prevaccine, −42 d to −1 d | 151 (15.6) | 261 (14.4) |
| Low risk | 111 (12.0) | 190 (10.9) |
| High risk‡ | 40 (97.2) | 71 (103.0) |
| Postvaccine, 0 to 42 d | 285 (29.5) | 367 (20.3) |
| Low risk | 244 (26.4) | 303 (17.4) |
| High risk‡ | 41 (99.6) | 64 (92.9) |
| Postvaccine, peak risk interval, 7 to 10 d | 125 (12.9) | 97 (5.4) |
| Low risk | 108 (11.7) | 73 (4.2) |
| High risk‡ | 17 (41.3) | 24 (34.8) |
Note: MMRV = measles–mumps–rubella–varicella vaccine, MMR+V = measles–mumps–rubella plus varicella vaccine, NA = not applicable.
*
Except where indicated otherwise.
†
Significant difference between vaccine groups (p < 0.001, by χ2 test of difference).
‡
Previous medical history that may predispose child to seizures.