A new study published in JAMA Pediatrics shows that children who are vaccinated against measles between 12 and 15 months are less likely to suffer fever or seizures than those vaccinated between 16 and 23 months.

The Centers for Disease Control and Prevention (CDC) recommends a first dose injection with a measles-containing vaccine at 12-15 months, with a follow-up “booster” between the ages of 4 and 6.

Approximately 85% of children will have received their first dose by the age of 19 months, but the study found that receiving the first dose by 15 months provides a benefit to children.

Researchers from the University of Washington carried out a retrospective cohort study at eight Vaccine Safety Datalink sites on a total of 840,348 children aged 12 to 23 months of age who had been vaccinated against measles from 2001 through 2011.

Read More: Early measles immunization reduces seizure risk