The Centers for Disease Control and Prevention, rarely the subject of public controversy, is facing an emerging credibility crisis on the emotional issue of whether old-style vaccines containing a mercury preservative caused autism in thousands of children.
The agency is being accused of cover-ups and scientific manipulations by a vocal group of autism advocates and is facing questions from some high-profile members of Congress.
As the debate and controversy increasingly finds its way into pediatricians' offices, average parents of healthy children are questioning whether vaccines are safe, sometimes even refusing inoculations.
The CDC and other public health officials insist such questions lack a basis in fact or science. Their greatest concern is that the broadening debate holds the potential to put a new generation of children at certain risk of deadly diseases if confidence in the safety of vaccines is lost and they don't receive recommended shots.
"I think it's huge," said Dr. Julia McMillan, a member of the American Academy of Pediatrics committee that makes vaccine recommendations. "There's no pediatrician in practice that doesn't confront this on a weekly basis: families who are questioning the need for – and in some cases refusing — vaccines for their children."
But the academy and the CDC are in agreement: They say there is no evidence to support a connection between autism and the mercury-based preservative thimerosal, which they stress is no longer used in most pediatric vaccines.
"We simply don't know what the cause of autism is," Dr. Bob Davis, the CDC's director of immunization safety, said Wednesday. Nonetheless, the CDC finds itself at the center of criticism.
A full-page ad scheduled to run in today's editions of USA Today, the nation's largest-circulation newspaper, accuses the CDC of "causing an epidemic of autism" by recommending that children receive a series of vaccines that until 2001 contained thimerosal.
The ad, placed by a group of autism advocacy groups, quotes environmental lawyer Robert F. Kennedy Jr. as saying: "It's time for the CDC to come clean with the American public."
But what stings public health advocates more is a letter sent Feb. 22 by Sen. Joseph Lieberman (D-Conn.) and seven other members of Congress. The bipartisan group asks that the CDC not take the lead on a new study examining the vaccine-autism issue. "If the federal government is going to have a study whose results will be broadly accepted, such a study cannot be led by the CDC," the group wrote Dr. David Schwartz, new director of the National Institute of Environmental Health Sciences. The institute, a part of the National Institutes of Health, will convene a panel in May to discuss how to analyze a key CDC database to determine whether autism rates have dropped since thimerosal was removed from vaccines.
The letter was also signed by Sen. Debbie Stabenow, (D-Mich.), Rep. Dave Weldon, (R-Fla.,) Rep. Chris Smith, (R-N.J.), Rep. Carolyn Maloney, (D-N.Y.), Rep. Dan Burton, (R-Ind.), Rep. Joseph Crowley, (D-N.Y,), and Rep. Maurice Hinchey, (D-N.Y.). Agency officials said Wednesday they are proud of the CDC's work on thimerosal safety issues and that they have looked hard to find a link as well as to find any other cause of autism.
"It was an unfortunate choice of language," Davis said of the Lieberman letter. "They and everyone else are certainly entitled to their opinion. We stand by all the research we have done."
Public health officials who work with CDC are more blunt.
"I think it's shocking," said Dr. Martin Myers, executive director of the National Network for Immunization Information and a professor of pediatrics at the University of Texas medical branch in Galveston.
"The loss of public trust in one of the most extraordinary institutions in the world. I'm not quite sure how that has occurred, but it has, and that's one of the unfortunate consequences," Myers said.
The controversy, which erupted as some autism advocates rallied on Capitol Hill today in conjunction with National Autism Month, is gaining political traction, moving well beyond an initial core of autism activists, CDC, public health and congressional officials all agree.
There are many parents of autistic children who believe, as do most pediatricians and scientists, that there is no scientific evidence that thimerosal caused autism and other neurological disorders. That issue was settled for most in a widely publicized 2004 report by an expert panel convened by the National Academy of Sciences Institute of Medicine.
But the report has been the subject of controversy and intense scrutiny since it was published.
Parents of many autistic children insist that thimerosal caused the disorder, because it appeared around the time their children received vaccinations. Their advocates also point to what they say is intriguing new research in animal models indicating that some individuals may be more sensitive to thimerosal than others. Martin Cowen, whose family lives in Jonesboro, is one such parent. Cowen is convinced thimerosal-containing vaccines caused his son Lindsey's autism. Lindsey, who turned 8 last week, does not speak, has not been toilet trained and cannot be allowed outdoors without being restrained for fear he'll run into traffic, his father said.
Cowen is highly skeptical of the CDC, a position shared by a cohort of parents and advocates across the country.
"An enormous effort is being made to deny the connection," he said of the CDC. "What do I think their motive is? They are very interested in having the herd vaccinated... They don't think of people as people suffering individually. It's the greatest good for the greatest number."
The National Immunization Program, run by the CDC, coordinates immunization activities across the country. Increasing the rate of immunization against disease is a cornerstone of public health.
At the same time, the CDC also is charged with monitoring vaccine safety. It's an inherent conflict of interest, said Weldon, a doctor before he was elected to Congress.
"They really do have a credibility problem," said Weldon, who serves on the committee that decides the CDC's budget. "Part of the credibility problem is it's asking them to investigate a problem that they may have created."
Weldon became involved in the thimerosal issue seven years ago. "Honestly, at first I was very dubious," he said. "As I looked at it more and more, I began to feel there is some validity to this."
Weldon said the recent interest by Lieberman and others on Capitol Hill is a sign the issue is gaining political traction. Lieberman was unavailable for comment. The controversy and public debate is likely to be further fueled by the full-page ad being paid for by a coalition of the autism activist groups led by Generation Rescue. The ad promotes a sophisticated Web site, www.PutChildren First.org, which includes links to CDC documents, e-mails and transcripts the groups say support their contention of an agency cover-up.
CDC spokesman Glen Nowak said many of the documents on the site have been in the public domain for years, and are presented out of context and in ways that may "look quite ominous" – when they're not.
"It's a very challenging issue," he said. The CDC is bracing for a spike in calls today from parents with questions and is increasing staffing at its public help line, 1-800-232-4636.