TABLE 1

Baseline Characteristics of Children With Vaccination-Related Seizures, With or Without Vaccination-Related Epilepsy Onset

Characteristics of ReportsAll Children (n = 990)PTotal No.Children With Vaccination-Related Epilepsy Onset and Stage 2 Follow-up (n = 23)PTotal No.
Vaccination-Related Epilepsy Onset (n = 26)Other Children (n = 964)Group I: Presumed Preexistent Encephalopathy (n = 3)Group II: Epileptic Encephalopathy (n = 12)Group III: Benign Epilepsy (n = 8)
Median age, mo (range), at
 First reported vaccination5.6 (2.2–16.2)11.6 (0.2–22.2).1549906.4 (5.6–15.1)4.7 (2.3–12.1)13.6 (4.7–16.2).00523
 Report of seizure to safety surveillance system10.8 (4.3–166)14.2 (0.3–73.4).86099011.9 (5.7–19.9)6.9 (4.3–166)16.4 (6.5–25.3).17123
 End of stage 1 follow-up19 (7–166)15 (0–105).00999018 (13–21)19 (9–166)23.5 (7–45).84723
Number of children with
 Male gender, (%)11 (42.3)509 (52.8).2909901 (33.3)5 (41.7)4 (50.0).685a23
 Multiple reports of seizures after vaccinations, (%)6 (23.1)23 (2.4%)<.0019901 (33.3)4 (33.3)1 (12.5).369a23
Number of reported seizures339891022417930
 Inactivated vaccine (versus attenuated vaccine, %)27 (81.8)668 (67.5).09010223 (75)17 (100)5 (55.6).019a30
 Temperature <38.5°C, (%)17 (54.8)193 (20.8)<.001*9613 (75)10 (66.7)3 (33.3).114a28
  • * P = .001 for inactivated vaccines and P = .018 for live attenuated vaccines; P = .025 for inactivated vaccines, when known Dravet syndrome was excluded.

  • a Fisher exact test, group III versus groups I and II.