PhotoIt doesn't make any difference when you have your children immunized against measles -- as long as you have it done, right? Not necessarily.

A new Kaiser Permanente study published in JAMA Pediatrics says kids receiving measles-containing vaccines at 12-15 months of age have a lower increased risk of fever and seizures than those who receive them at 16-23 months of age.

The Centers for Disease Control and Prevention (CDC) recommends a two-dose series of measles-containing vaccines, with the first dose administered at 12-15 months and the second dose at 4-6 years of age. Most children receive their first dose of a measles-containing vaccine between the ages of 12 and 23 months; approximately 85% receive it by 19 months of age. The study found that receiving the first dose by 15 months provides a benefit to children.

"We found that the magnitude of increased risk of fever and seizures following immunization with measles-containing vaccines during the second year of life depends on age," said Ali Rowhani-Rahbar, MD, MPH, PhD, lead author of the study. "While measles-containing vaccines administered at 12-15 months of age are associated with a small risk of fever and seizures following immunization, delayed administration at 16-23 months of age results in a greater risk of those adverse events."

In line with CDC

Previous studies have shown that these vaccines administered to children 12-23 months of age are associated with an increased risk of febrile seizures one to two weeks following immunization. This is the period of time during which the vaccine virus replication is at its peak, potentially causing fever. The resulting fever may cause some children to experience a seizure.

"Kaiser Permanente's guidelines for measles-containing vaccines are in line with the CDC's recommendations," said Matthew F. Daley, MD, a pediatrician and senior investigator at Kaiser Permanente Colorado's Institute for Health Research. "This study's findings reinforce for parents that these vaccines are safer when children receive them at 12 to 15 months of age."


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