Delayed childhood vaccines not beneficial, study says

Two University of Louisville School of Medicine doctors have concluded that delaying childhood vaccinations does not improve children’s health, according to a study in the medical journal Pediatrics.

The study was prompted after links between autism and thimerosal, a preservative used in many vaccines, were discredited. After the link was discredited, some autism advocates began to argue that neurodevelopmental problems were caused by overloading children’s immune systems with too many vaccines early in life.

As a result of these arguments, parents have begun to request alternate vaccine schedules that spread vaccines out even though there is no medical evidence to suggest this is helpful.

University of Louisville School of Medicine pediatric infectious disease specialists Dr. Michael J. Smith and Dr. Charles R. Woods began to analyze the data on 1,047 children who had initially been enrolled in an earlier study to determine whether thimersol posed an autism risk.

Smith and Woods took this approach because researchers cannot ethically perform clinical trials of delayed vaccinations due to the potential risk to children.

The children in the original study were all born between 1993 and 1997, vaccinated on a schedule of their parents choosing and were then subjected to series of neurophysical tests between the ages seven and ten.

Under half of the children - 491 children - were vaccinated on a timely basis. An additional 235 received all vaccinations, but not on schedule, and the remaining children received some but not all vaccines.

The study by Smith and Woods, which was published May 24 in the medical journal Pediatrics, concluded that delaying vaccines did not improve the outcomes to the tests. In fact, a Los Angeles Times report said the doctors found that children who were vaccinated on a regular schedule performed higher on 15 of the 42 tests than those who weren’t.

“This study provides the strongest clinical outcomes evidence to date that on-time receipt of vaccines during infancy has no adverse effect on neurodevelopmental outcomes 7 to 10 years later,” Smith and Woods concluded in their article, according to the Los Angeles Times. “These results offer reassuring information that physicians and public health officials may use to communicate with parents who are concerned that children receive too many vaccines too soon.”