Vaccinate on schedule
Delaying MMR Vaccine in 2nd Year Linked to Higher Seizure Risk — Physician’s First Watch
Delaying MMR Vaccine in 2nd Year Linked to Higher Seizure Risk
By Kelly Young
Receiving the measles, mumps, and rubella (MMR) vaccine later than the recommended age of 12 to 15 months increases seizure risks, a self-controlled case series analysis in Pediatrics concludes.
Researchers searched a vaccine safety database to identify 5700 children who received vaccines and had a seizure in the days after vaccination. Using the unexposed pre-vaccination period and after the post-vaccination risk window, each child also served as its own control.
The incidence rate ratio (IRR) for seizures after receiving the MMR vaccine at 12 to 15 months was 2.65, but if vaccination was delayed to 16 to 23 months, the IRR increased to 6.53. Seizure risks were higher when the vaccine also included varicella (MMRV). There was no increased seizure risk associated with vaccines (such as rotavirus) in the first year of life.
Dr. Deborah Lehman, an associate editor at NEJM Journal Watch Pediatrics and Adolescent Medicine, comments: "Delays in vaccine administration are known to result in disease outbreaks. This cohort study ... provides further support for vaccinating children on time and per CDC recommended schedules. MMR and MMRV should be administered between 12-15 months."