This new study suggests the theory of overloading an infant's immune system is highly unlikely.
Even though children are given far more vaccines than prior generations, the practice does not appear to weaken their immune systems or make them more prone to other infections, a US study said Tuesday.
The report in the Journal of the American Medical Association marks the first time researchers have probed a link between the current recommended immunization schedule -- which includes up to 16 vaccinations -- and the rate of infections and illnesses that are unrelated to vaccines among children in the United States.
"It's understandable that parents across the US have questions and concerns about vaccine safety," said co-author Matthew Daley, a Kaiser Permanente pediatrician.
"This latest study found that vaccination didn't appear to damage the immune system in a way that made kids more infection-prone. This finding will hopefully provide additional reassurance to parents about the safety of the recommended schedule."
A random sample of 193 children who had been diagnosed with respiratory and gastrointestinal illness, along with other viral and bacterial infections, were compared to a control group of 751 children who had not been diagnosed with these infections.
Scientists looked at levels of exposure to vaccine antigen -- a protein or other substance that induces an immune response in the body -- in children's first 2 years of life.
They total vaccine antigen exposure "was not associated with an increased risk of infections not targeted by vaccines over the next 24 months of life," said the study.
"Some parents are concerned that multiple vaccines in early childhood could damage their child's immune system, making them more susceptible to future infections," said lead author Jason Glanz, senior investigator at the Kaiser Permanente Colorado Institute for Health Research.
"This new study suggests the theory of overloading an infant's immune system is highly unlikely."
Experts urge parents to talk with their pediatrician if they have concerns about vaccine safety.