Timely versus delayed early childhood vaccination and seizures.

View Abstract

BACKGROUND

Little is known regarding the timing of childhood vaccination and postvaccination seizures.

METHODS

In a cohort of 323 247 US children from the Vaccine Safety Datalink born from 2004 to 2008, we analyzed the association between the timing of childhood vaccination and the first occurrence of seizure with a self-controlled case series analysis of the first doses of individual vaccines received in the first 2 years of life.

RESULTS

In infants, there was no association between the timing of infant vaccination and postvaccination seizures. In the second year of life, the incident rate ratio (IRR) for seizures after receipt of the first measles-mumps-rubella vaccine (MMR) dose at 12 to 15 months was 2.65 (95% confidence interval [CI] 1.99-3.55); the IRR after an MMR dose at 16 to 23 months was 6.53 (95% CI 3.15-13.53). The IRR for seizures after receipt of the first measles-mumps-rubella-varicella vaccine (MMRV) dose at 12 to 15 months was 4.95 (95% CI 3.68-6.66); the IRR after an MMRV dose at 16 to 23 months was 9.80 (95% CI 4.35 -22.06).

CONCLUSIONS

There is no increased risk of postvaccination seizure in infants regardless of timing of vaccination. In year 2, delaying MMR vaccine past 15 months of age results in a higher risk of seizures. The strength of the association is doubled with MMRV vaccine. These findings suggest that on-time vaccination is as safe with regard to seizures as delayed vaccination in the first year of life, and that delayed vaccination in the second year of life is associated with more postvaccination seizures than on-time vaccination.

Abbreviation
Pediatrics
Publication Date
2014-06-01
Volume
133
Issue
6
Page Numbers
e1492-9
Pubmed ID
24843064
Medium
Print
Full Title
Timely versus delayed early childhood vaccination and seizures.
Authors
Hambidge SJ, Newcomer SR, Narwaney KJ, Glanz JM, Daley MF, Xu S, Shoup JA, Rowhani-Rahbar A, Klein NP, Lee GM, Nelson JC, Lugg M, Naleway AL, Nordin JD, Weintraub E, DeStefano F