Timely Versus Delayed Early Childhood Vaccination and Seizures

Abstract

WHAT'S KNOWN ON THIS SUBJECT: Reasons for childhood immunization delay include parental intent and barriers such as transportation. To date there has been 1 study of the association of delayed vaccination and seizures, which found measlesmumps-rubella and measles-mumps-rubella-varicella vaccines are both associated with a higher rate of seizures if received after 15 months of age.WHAT THIS STUDY ADDS: Our study found no association between the timing of vaccination and occurrence of seizures in the first year of life. By using different methods, our results support the observation that delaying vaccination with measles-containing vaccines past 15 months of age increases the incidence of postvaccination seizures. abstract BACKGROUND: Little is known regarding the timing of childhood vaccination and postvaccination seizures.

Safety of Measles-Containing Vaccines in 1-Year-Old Children

“…This study further confirmed (by using previously unanalyzed data) that MMRV and MMR + V are both associated with fever and seizure 7 to 10 days after vaccination, and validated our previous findings and those of others that MMRV versus MMR + V is associated with an excess risk of seizures 7 to 10 days after vaccination. 19,20,[34][35][36] This study replicated previously reported safety findings, which provides additional reassurance that assessing the 7 main outcomes with this approach was reasonable.…”

Vaccination uptake by vaccine-hesitant parents attending a specialist immunization clinic in Australia

“…12,32 This is concerning as selective or delayed immunization schedules do not have an equivalent safety profile to complete immunization. 47,48 Additionally, parents who intentionally omit or delay immunizations are significantly less likely to have received all scheduled immunizations by 19 months of age leading them to be less protected. 49 The long-term impact of selective schedules on herd immunity is also unknown.…”

Three randomized trials of maternal influenza immunization in Mali, Nepal, and South Africa: Methods and expectations

“…Furthermore, in a randomized controlled trial in Bangladesh, administration of inactivated influenza vaccine in the third trimester of pregnancy was associated with reduction of confirmed influenza (using rapid ELISA test) by 63% among infants younger than 6 months of age [13]. Maternal influenza immunization has also been associated with protection against adverse birth outcomes such as prematurity and small for gestational age birth in observational studies and post-hoc analyses of trial data [3,14], although this finding has not been consistently observed by others [15] (particularly in studies that do not account for influenza infection/circulation). Consequently, whereas these advances are promising, many questions remain.…”