Vaccine Studies: Examine the Evidence - American Academy of ...

Evaluation of Immunization Rates andSafety Among Children With InbornErrors of MetabolismKlein N, et al., Pediatrics. 2011; 127(5),e1139-46http://pediatrics.aappublications.org/content/127/5/e1139Measles-Containing Vaccines andFebrile Seizures in Children Age 4 to 6YearsKlein N, et al., Pediatrics. 2011; 129(5):809-14http://pediatrics.aappublications.org/content/129/5/809Researchers studied children in NorthernCalifornia to determine whether 77 infantswith inborn errors of metabolism whoreceived vaccines were more likely toexperience adverse events followingvaccination, than 1540 matched controls(infants born without inborn errors ofmetabolism). Authors did not find anyassociation between vaccination of childrenwith inborn errors of metabolism and anincrease in hospitalizations or emergencydepartmentvisits within 30 days ofvaccination.Researchers chose to perform cohort studyand included 715,484 children aged 48-83months of age who received a dose ofMMRV, a dose of MMR on the same day asa dose of Varicella injected separately, orMMR alone or Varicella alone to determinethe risk of post-vaccination seizure in thesegroups. Results showed that more feversand seizures did occur in children who hadreceived the MMRV vaccine, comparedwith children who had received MMR +Varicella, or MMR or Varicella separately,though this finding was not statisticallysignificant. The study did not find any peakin seizure or fever activity in any of thestudy groups in the 7-10 post-vaccinationperiod. Of the 4 febrile seizures observed inthe 7-10 days in the post-vaccination periodfor children receiving MMRV, only oneOn-time receipt of vaccines is notassociated with increased risk for seriousadverse events in the 30 days aftervaccination, even in children who havemetabolism conditions. This shouldprovide reassurance that children withinborn errors of metabolism who arevaccinated routinely do not experienceadverse effects.Overall researchers found no increased riskof febrile seizures in any of the studygroups within 6 weeks of vaccination.