University of Louisville researchers have determined that there is no benefit to delaying immunizations during the first year of life. The study, which was published in the journal Pediatrics, looked at the health records of 1,047 children. Researchers determined that varying the immunization schedule may actually be dangerous for infants.
The study data comes with a recent uptick in the number of parents who try to spread out the shots, the L.A. Times notes, even after the discrediting of the thimerosal-autism link. Some advocates have argued that neurodevelopmental problems are caused by overloading children's immune systems with too many vaccines too early in life. But there is no evidence to suggest that spreading out the shots is helpful.
Using records collected for a previous VaccineSafety Datalink study of thimerosal exposure, researchers compared children's performance on 42 neuropsychological tests with the timeliness of vaccinations during their first year of life. The developmental tests, given when the children were between the ages of 7 and 10, included assessments of speech and language, fine motor coordination, behavior regulation, general intellectual functioning and other abilities.
Children with timely receipt of vaccination were compared with those who had delays in receipt of one or more doses. Those who received the maximum number of vaccines in the first seven months of life were compared with those who received the fewest vaccines in the study group. Researchers found no evidence to suggest that multiple vaccines in the first year of life affect a child's cognitive abilities later. In fact, children who received each dose of each vaccine on time performed better on two of the 42 tests, after adjustment for familial and socioeconomic factors. Those who missed or were late on one or more doses of vaccine did not perform better on any test.
"As the visible threats of vaccine-preventable diseases have decreased, parental concerns about vaccine safety have increased," explains lead author and pediatric infectious diseases specialist Michael Smith. "I hope this study will reassure parents that vaccinating their children is not just safe but the right thing to do to protect their children against potentially deadly diseases."
Vaccine expert Dr. Gary Freed, director of the Child Health Evaluation and Research Unit at the University of Michigan Health System, said he wasn't surprised by the findings, since "there's never been any evidence whatsoever that delaying vaccines does any good for any child." And the reason children receive so many vaccines at such young ages is because "the life-threatening diseases that they protect against are most likely to attack at these ages," he said, as quoted by HealthDay.
CDC researcher said the new findings send an important message: Parents who contemplate delaying vaccination "should realize that there aren't any specific benefits, and that they are putting their child at risk, and not only their child but also the community," says Dr. David Sugerman, of the CDC's Epidemic Intelligence Service in Atlanta, as quoted by Reuters.