Amid worries about autism, delaying or forgoing childhood vaccines has become increasingly popular, but a new study suggests this practice does not lead to better long-term outcomes for kids.

Researchers looked at data from a battery of 42 neuropsychological tests conducted on more than 1,000 children between the ages 7 to 10. They report in the June issue of the journal Pediatrics that children who were vaccinated following the recommended immunization schedule exhibited better verbal skills, had higher IQs and were less likely to stutter than children who received vaccines on a delayed schedule.

Meanwhile children who did not receive vaccines on time performed no better than children who did on any of the tests which looked at speech, fine motor skills, executive-functioning and behavior, among other skills.

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“The lack of any statistically significant results that favored delayed receipt of vaccines in the first year of life sends a clear public health message that should be comforting to many parents with vaccine safety concerns: children can receive their immunizations on time and expect to have the same neurodevelopmental outcomes as children with any other pattern of vaccine receipt,” the study authors write in their findings appearing online ahead of publication in Pediatrics.

Of the 1,047 children studied, 47 percent were vaccinated on time. Some of the remaining children received all of the recommended vaccines but on a delayed schedule, and some did not finish the series of recommended shots.

Children who were not immunized on schedule typically came from lower income households and were more likely to have mothers who did not have college degrees, the study indicates, which could be one reason for the lower performance of kids in this group. But the authors note that the average household income for children in each group was “well above the poverty level.”

A recent study found that 39 percent of parents declined vaccines or delayed immunizations for their children in 2008, up from 22 percent in 2003. While there are a variety of reasons children are not vaccinated on time — including everything from limited medical care to parental choice — now debunked fears of a link between autism and the measles, mumps and rubella, or MMR, vaccine continue to be one reason parents don’t follow the recommended vaccination schedule.