MEASLES-CONTAINING VACCINES AND FEBRILE SEIZURES IN CHILDREN AGE 4 TO 6 YEARS

Monday, 1st of September 2014

[source]Pediatrics[|source]

 In 2008, combination measles-mumps-rubella-varicella (MMRV) rapid cycle analysis of safety monitoring data detected a possible increased risk for seizures after receipt of MMRV. Subsequent studies confirmed that among toddlers 12 to 23 months old, ages when the risk for febrile seizure peaks, measles-containing vaccines were associated with elevated risk of fever and febrile seizure and MMRV was associated with an estimated 2-fold increased risk of fever and febrile seizures occurring 7 to 10 days after MMRV compared with separately administered MMR + V..

MMR administered as a second dose to 4- to 6-year-old children has not been reported to have an association with an increased risk for febrile seizures. Whether either MMRV or MMR + V is associated with an increased risk for febrile seizures among children aged 4 to 6 years has not been previously investigated. In this report, the authors assess the risk for febrile seizures after MMRV and MMR + V administration among children aged 4 to 6 years, ages when the risk for febrile seizure is much lower than that for toddlers. The report documents that there is no evidence that MMRV or MMR + V is associated with an elevated risk of febrile seizures among 4- to 6-year-olds during the 6 weeks after vaccination. More details on findings and recommendations are accessible at: http://pediatrics.aappublications.org/content/129/5/809.long

 

ABSTRACT

BACKGROUND: In the United States, children receive 2 doses of measles-mumps-rubella vaccine (MMR) and varicella vaccine (V), the first between ages 1 to 2 years and the second between ages 4 to 6 years. Among 1- to 2-year-olds, the risk of febrile seizures 7 to 10 days after MMRV is double that after separate MMR + V. Whether MMRV or MMR + V affects risk for febrile seizure risk among 4- to 6-year-olds has not been reported.

METHODS: Among 4- to 6-year-old Vaccine Safety Datalink members, we identified seizures in the emergency department and hospital from 2000 to 2008 and outpatient visits for fever from 2006 to 2008 during days 7 to 10 and 0 to 42 after MMRV and MMR + V. Incorporating medical record reviews, we assessed seizure risk after MMRV and MMR + V.

RESULTS: From 2006 through 2008, 86 750 children received MMRV; from 2000 through 2008, 67 438 received same-day MMR + V. Seizures were rare throughout days 0 to 42 without peaking during days 7 to 10. There was 1 febrile seizure 7 to 10 days after MMRV and 0 after MMR + V. Febrile seizure risk was 1 per 86 750 MMRV doses (95% confidence interval, 1 per 3 426 441, 1 per 15 570) and 0 per 67 438 MMR + V doses (1 per 18 282).

CONCLUSIONS: This study provides reassurance that MMRV and MMR + V were not associated with increased risk of febrile seizures among 4- to 6-year-olds. We can rule out with 95% confidence a risk greater than 1 febrile seizure per 15 500 MMRV doses and 1 per 18 000 MMR + V doses.