Timely Versus Delayed Early Childhood Vaccination and Seizures

Get MMR and MMRV Vaccines On-Time, Reduce Risk of Febrile Seizures in Children

Centers for Disease Control and Prevention (CDC) sent this bulletin at 05/22/2014 03:05 PM EDT

A new article in Pediatrics, titled “Timely Versus Delayed Early Childhood Vaccination and Seizures”, reconfirms that in order to best protect children from disease – and to avoid a higher risk of febrile seizures – children should be vaccinated with their first measles, mumps, and rubella (MMR) or measles-mumps-rubella-varicella (MMRV) dose at the recommended 12-15 months of age. Previous studies have shown that measles-containing vaccines (MMR and MMRV) occasionally may cause febrile seizures.  This study demonstrates that delaying vaccination with MMR or MMRV in the second year of life (past the recommended ages of 12-15 months) could put some children at greater increased risk for febrile seizures when they receive these vaccines. In the first year of life, there is no relationship between the recommended vaccine schedule and seizures.

To view this manuscript in its entirety, click here.

CDC offers a number of vaccine safety resources to help providers:

• CDC Vaccine Safety
• ACIP Recommendations: Use of Combination Measles, Mumps, Rubella, and Varicella Vaccine
• CDC Immunization Schedules
• Information on Measles Vaccine

• Article

Timely Versus Delayed Early Childhood Vaccination and Seizures

1. Simon J. Hambidge, MD, PhD^a,^b,^c,^d, 
2. Sophia R. Newcomer, MPH^a,
3. Komal J. Narwaney, MD, PhD^a, 
4. Jason M. Glanz, PhD^a,^d,
5. Matthew F. Daley, MD^a,^c, 
6. Stan Xu, PhD^a, 
7. Jo Ann Shoup^a,
8. Ali Rowhani-Rahbar, MD, PhD^e, 
9. Nicola P. Klein, MD, PhD^f,
10. Grace M. Lee, MD, MPH^g,^h, 
11. Jennifer C. Nelson, MPHⁱ, 
12. Marlene Lugg, DrPH^j, 
13. Allison L. Naleway, PhD^k, 
14. James D. Nordin, MD, MPH^l,
15. Eric Weintraub, MPH^m, and 
16. Frank DeStefano, MD, MPH^m

+Author Affiliations

1. ^aInstitute for Health Research, Kaiser Permanente Colorado, Denver, Colorado;
2. ^bDepartment of Community Health Services, Denver Health, Denver, Colorado;
3. ^cDepartment of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado;
4. ^dDepartment of Epidemiology, University of Colorado School of Public Health, Aurora, Colorado;
5. ^eDepartment of Epidemiology, School of Public Health, University of Washington, Seattle, Washington;
6. ^fKaiser Permanente Vaccine Study Center, Oakland, California;
7. ^gDepartment of Population Medicine, Harvard Pilgrim Health Care Institute and Harvard Medical School, Boston, Massachusetts;
8. ^hDivision of Infectious Diseases and Department of Laboratory Medicine, Boston Children's Hospital, Boston, Massachusetts;
9. ⁱGroup Health Research Institute, Seattle, Washington;
10. ^jDepartment of Research and Evaluation, Southern California Kaiser Permanente, Pasadena, California;
11. ^kKaiser Foundation Hospital Center for Health Research, Kaiser Northwest, Portland, Oregon;
12. ^lHealth Partners Research Foundation, Minneapolis, Minnesota; and
13. ^mImmunization Safety Office, Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia

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.

Key Words:

• vaccine safety
 
• immunization
 
• vaccine
 
• seizures
 
• vaccine delay

• Accepted March 17, 2014.

• Copyright © 2014 by the American Academy of Pediatrics