Children who receive their DTaP vaccination in the thigh rather than the arm are less likely to have a bad reaction at the site of the shot, a new report shows.
In a study that looked at data from 1.4 million children, researchers found that kids younger than 3 were almost twice as likely to have a reaction that landed them in the doctor’s office or the emergency room when they got their shots in the arm instead of the thigh, according to the report published in Pediatrics.
While reactions at the site of the shot aren’t dangerous, they can be troubling to parents, says the study’s lead author Dr. Lisa Jackson, a senior investigator at Group Health Research Institute. “We want to see if we can limit the more severe end of them,” she adds.
Some pediatricians steer away from injecting the thigh because an earlier version of the DTaP vaccine could cause such painful site reactions that kids didn’t want to walk after getting vaccinated in the leg, Jackson explains. The reactions to the newer vaccine are less painful, so that’s not a problem.
Jackson and her colleagues are hoping that the new research will prompt more pediatricians to choose the thigh rather than the arm for this vaccine.
The DTaP is designed to protect against diphtheria, tetanus and pertussis, and is one of the recommended childhood immunizations. It is often required before kids can attend school.
Children receive a course of five inoculations, which are usually given at ages 2 months, 4 months, 6 months, 15-18 months, and 4-6 years.
For the new study, Jackson and her colleagues pored through data gathered between 2002 and 2009 from several sites around the nation on childhood immunizations. They found that there was little risk of a shot site reaction when kids were vaccinated against the flu and hepatitis A.
But reactions were much more common for DTaP and the risk was higher if the shots were given in the arm rather than the thigh. Among children aged 12 to 35 months the risk of a reaction was 88 percent higher when the shot was given in the arm. Among those aged 3 to 6 years the risk was 41 percent higher.
Overall, about 1 percent of kids end up with a reaction at the site of the shot. Those reactions can range from a little redness to a completely swollen limb, says Dr. Marian Michaels, a professor of pediatrics at the Children’s Hospital of Pittsburgh at the University of Pittsburgh School of Medicine.
“That can be very scary for the family,” Michaels says. “This study may help with decreasing some of those adverse events.”
Still, says Jackson, it’s important for parents to realize that a small reaction at the site of the shot means that the vaccine is doing what it’s supposed to. The shot should stimulate an immune response, “and part of that is an inflammatory response,” she explains.