For years, the Centers for Disease Control and Prevention has maintained that no direct link exists between early vaccinations and developmental disorders in children, but not everyone wants to give the last word on the subject to the government public health agency.
Lawmakers on Capitol Hill — responding to a growing clamor from parents and advocacy groups who argue the rise in the number of autistic children is linked to childhood vaccines — say they want the CDC out of the business of vaccine safety. Their argument is that the agency is tainted by conflicts of interest because it is also the chief promoter for vaccinations.
Congress was too busy wrestling with a host of issues, including the war on terror, high gas prices and appropriations bills to turn its attention toward the health issue before it recessed on Sept. 29. The 109th Congress will return after the Nov. 7 election to wrap up unfinished business, but it's unlikely to touch on any legislation relating to the matter.
Rep. Dave Weldon of Florida, one of a dwindling number of Republicans with safe seats this year, said he will reintroduce his bill — the Vaccine Safety and Public Confidence Assurance Act of 2006 — when the 110th Congress convenes next year.
"It's an important issue. As a physician, I've been surprised and frankly embarrassed about the overall lack of good research into vaccine safety," Weldon told FOXNews.com.
Weldon introduced the bill with Rep. Carolyn Maloney, D-N.Y., over the summer. It now sits in a subcommittee of the House Energy and Commerce Committee.
The legislation would create a separate agency outside of the CDC to oversee vaccine safety issues, including research. Other legislation introduced by other House and Senate sponsors addresses linkages between vaccines and autism-related disorders.
The CDC says recent studies indicate no link between autism and childhood vaccinations, even one that contained mercury, a position supported by many in the medical establishment.
With such conflict, the debate is raging over how limited current research really is and whether the government is doing enough to fund better studies.
"Parents deserve answers," Maloney said when the bill was introduced. "As the most scientifically advanced country in the world, we should be able to conduct a comprehensive study of the health effects of vaccines to restore absolute trust in the nation's vaccine program."
Allegations of a conflict of interest are flatly denied by the CDC.
"We do take our role here very seriously and we empathize with the parents of children with autism," said Curtis Allen, spokesman for the CDC, who said he could not comment directly on any specific legislation.
"(The) CDC is sensitive to concerns about potential conflicts of interest by employees, particularly given CDC research and recommendations can have substantial implications for vaccine manufacturers," Allen said. "The integrity of CDC’s vaccine safety research and its reputation for excellence are among the most valued assets of our agency."
As for the CDC's focus on vaccine safety, Allen said, "We carefully evaluate allegations of harmful vaccine effects and are prepared to adjust our policies if allegations prove scientifically valid."
In 2005, Dr. Frank DeStefano, acting chief of immunization safety for the CDC told FOXNews.com, "Autism is a serious developmental disability and has a great effect on the individual and their families, and there is great impetus of need among families and society and the government to find out what is causing autism and what can be done to prevent it."
However, he said, the current body of evidence on the safety of vaccinations is strong.
“Our judgment is that vaccines are safe and the evidence today indicates that vaccines are not linked to autism," said DeStefano.
Still, Weldon questions whether the CDC's conclusions are based on enough sound, objective research, particularly in the area of mercury. Up until 2000, mercury-based thimerosal was used in all childhood vaccines as a preservative. Many blamed it for an increase in emerging autism cases.
Pharmaceutical companies stopped using thimerosal six years ago upon the recommendation of the federal government, even though the government never gave official acknowledgement that mercury levels in vaccines could cause developmental problems in children.
Government officials said that infants had not been exposed to high enough levels of mercury through the thimerosal, but its removal was done as "a precaution."
An independent study conducted by Drs. Mark and David Geier in 2003 concluded that a link does exist between thimerosal and autism. But the Institutes of Medicine, contracted by the CDC to study the possible linkage, released findings in 2004 that found no connection. That study is still used by the agency today as the official position on the issue.
Nevertheless, Wendy Fournier, a spokeswoman for the National Autism Association, contends that the CDC's lack of independence from industry influence, has contributed to a conflict of interest on its key panel for safety oversight. Most of the conflicts cited are attributed to members of the CDC's Advisory Committee on Immunizations Practices with financial ties to pharmaceutical companies making vaccines.
"We're hoping Congress does the right thing and sees the conflict here," said Wendy Fournier, spokeswoman for the National Autism Association.
Supporters deny that oversight panelists are clouded by conflicts of interest.
"As a current member of the Committee on Infectious Diseases of AAP (the American Academy of Pediatrics), I have attended many sessions where possible vaccine-associated adverse effects, either immediate or delayed, were discussed," said Dr. Lorry Rubin, chief of the Pediatric Infectious Diseases Schneider Children's Hospital, Long Island.
"It has been my observation that all valid scientific information has been presented and discussed," Rubin said, adding, "My personal opinion of the studies of which I am aware, of possible vaccine adverse events performed by CDC, is that they were sound studies."
He said the AAP had no comment on the Weldon bill that would create a separate agency for vaccine safety.
Meanwhile, parents are struggling to understand how the number of autistic children ages 6 through 21 served by special education programs in the U.S. has increased 500 percent over the last decade, reaching more than 140,000 in 2004. Experts now estimate that one in every 166 children in the United States has been diagnosed with autism.
"I always thought these people raising concerns (about vaccines) were wackos," said Vicky Debold, a nurse and mother of an autistic child, and also director of the Coalition for SafeMinds.
Debold said she began intense research after her son was diagnosed, and started doubting the levels of mercury in the vaccines. But the body of evidence is woefully inadequate and needs to be increased.
"I think Rep. Weldon's bill is right on the mark," she said. "If the public understood that the government was trying to improve vaccines and addressing vaccine concerns, then the public would be more inclined to vaccinate with confidence."
Editor's note: This story has been corrected to reflect that most members of the medical establishment support the CDC's claims that no clear evidence has been found of a link between vaccines and autism. The story inadvertently stated that the opposite was true.