Should my child still be using a booster seat?

Flickr/ Neeta Lind

Right around the time he turned 7, Jameson Mannix started dreading the ride to school. That was the age he realized he was the only boy in his class still using a booster seat. When he complained, his mother, Rebekah Mannix, MD, MPH, of Boston Children’s Division of Emergency Medicine, explained that without a booster seat the seat belt wouldn’t fit him correctly because his seat belt rested on his throat and stomach instead of lying across his hips and chest. In the event of a crash, she told him, the belt could damage his intestines and spine, which is very dangerous.

But Jameson, like most kids his age, was far more concerned with “fitting in” than a well-fitting seatbelt.

“No matter how much we discussed it, Jameson kept going back to the fact that he was the only one in his class that had to use a booster seat,” Mannix remembers. “I told him that in Massachusetts there was a law requiring kids under 8 years old or 4 feet, 9 inches to use a booster seat, which meant he technically HAD to use one. That resonated with him a little, but he still fought it almost every morning.”

To help drive home the point, Mannix began researching data on the effectiveness of booster seats and booster seat laws on deaths and injuries related to car accidents, in hopes of strengthening her case for Jameson that booster seat laws for children his age existed for a reason. As she scanned the available data she found plenty of studies linking booster seats to decreased fatalities and injuries, but noticed that laws stating how old or tall children needed to be before they could legally travel without a booster changed from state to state.

Rebekah Mannix, MD, MPH

The varying data didn’t paint a very clear picture of how effective booster seat laws were throughout the country, but Mannix saw the discrepancy as an opportunity. If she could conduct a formal study proving that booster seats save the lives of children from 6 to 7 years old—and link those saved lives to stricter booster seat laws—she believed the information could help convince lawmakers to require booster seat laws for older children in more states, eventually saving more lives.

Mannix and a team of researchers pored over data from Fatality Analytic Reporting System, which is a database of crashes in which at least one person is killed. Child deaths related to crashes were analyzed, looking specifically at whether the crashes and resulting deaths or injuries took place in a state with or without a booster seat law. If the state did have a booster law, the team noted its age and height requirements. The results varied on how strict the laws were, but the overall findings were clear: booster seat laws saved the lives of children, especially those children in the 6- to 7-year age group. Key findings include:

  • States with booster seat laws for children 4 to 6 had a roughly 20 percent lower rate of death and incapacitating injury from motor vehicle crashes than states without booster seat laws.
  • States with booster seat laws that extended to 6- and 7-year-olds had a 35 percent decrease in death or incapacitating injury.

“Based on our findings, booster seat use for children under the age of 8, or 4 feet, 9 inches, really should go beyond causal suggestion,” Mannix says. “It’s clear that these laws save lives and we recommended all states adopt them.”

“Booster seat use for children under the age of 8, or 4 feet, 9 inches can save lives.” –Dr. Mannix

“At the end of the day we all want children to be safe,” adds Lois Lee, MD, MPH, Mannix’s co-worker at Boston Children’s Emergency Medicine Division and co-author on the study. “This study shows that these laws help protect children, and we hope it can convince lawmakers to create or adapt laws that require kids to be in the proper child passenger restraint (car seat and booster seat) until the recommended age and height.”

Whether the findings will inspire lawmakers to increase age and height limits on the varying booster seat laws out there remains to be seen, but based on Jameson’s response, there’s a good chance Mannix and her team’s research could lead to change.

“After all we went through, Jameson is now very proud of the role he played in this research,” laughs Mannix. “He’s since outgrown the need for a booster, but delights in telling his younger sister that she needs to use one to be safe. ‘Booster seats save lives, Cordelia,’ is his new favorite saying every time we all get in the car.”