Posted on Tue, Feb. 06, 2007

Fact: No link of vaccine, autism

Arthur Caplan

is the Emanuel and Robert Hart Professor of Bioethics at the 
University of Pennsylvania, where he co-directs the Ethics and 
Vaccines Project

What must it be like to spend a huge amount of time every waking day 
trying to change public health practice - only to find out that you 
were wrong?

That is precisely what has happened to the proponents of the theory 
that mercury in vaccines - contained in the preservative thimerosal, 
which once was used (and is used no longer) in vaccines - is 
responsible for a nearly 20-year explosion in autism and other 
neurological disorders among American children.

This urban legend has had very real - and terrible - consequences. It 
has led, and continues to lead, many parents to avoid getting their 
kids and themselves vaccinated against life-threatening diseases. The 
failure to vaccinate has caused many preventable deaths and avoidable 
hospitalizations from measles, whooping cough, diphtheria, flu, 
hepatitis and meningitis. And fear of vaccines puts each one of us at 
risk that we, our children or grandchildren will become part of a 
deadly outbreak triggered by someone whose parents avoided getting 
their child vaccinated for fear of autism.

Recent research on many fronts in medicine and science has nailed the 
coffin shut on the mercury-in-vaccines-causes-autism hypothesis. The 
connection is just not there. Perhaps the key fact, which has 
garnered little attention, is that thimerosal has been removed from 
vaccines in this and other countries for many years, with no obvious 
impact on the incidence of autism. The most recent data point toward 
a correlation with nothing at all to do with vaccines: the increasing 
age at which people (particularly men) have children seems to be 
associated with an increase in autism and other neurological problems.

Still, some of the most fervent anti-vaccine critics cannot let go. 
They continue to tell devastated parents of children with autism that 
vaccines are to blame. Others are still out on the lecture circuit 
peddling books and articles that bash vaccines and invoke mercury as 
a problem. Still others pepper the Internet with the false message 
that vaccines and autism do go hand in hand - it is just that the 
government, or the pharmaceutical companies, or organized medicine, 
or all of them, are keeping the truth from us all.

Less than two years ago, Robert Kennedy Jr. published an article in alleging that the government knew of and covered up the 
autism-vaccines connection. Thimerosal was, Kennedy told large 
audiences and many media reporters, to blame.

Kennedy was hardly alone in fingering vaccines as the cause of the 
epidemic of autism affecting American children. David Kirby's 2005 
best-selling book, Evidence of Harm, and many other articles, 
newsletters and advocacy blogs fanned the flames. Some continue to do 

Proponents of the thimerosal/mercury-causes-autism theory have had a 
powerful impact on public opinion. When one of my students recently 
conducted a pilot study of attitudes about the new cervical-cancer 
vaccine, fears about autism were prominent among the reasons many 
respondents gave for being wary of the vaccine. Friends of mine 
continue to tell me of parents in Lafayette Hill, Voorhees, 
Greenville and Downingtown who won't have their children vaccinated 
because of the risk of autism. States continue to allow parents to 
opt out of vaccines on "philosophical" grounds - perhaps the only 
arena in American public life where "secular philosophy" is given 
legal standing in public policy. And even some young health-care 
workers report that they don't get important vaccines that would 
protect them, their families and their vulnerable patients against 
death because of worries about autism and vaccines.

Science and medicine have not bought the thimerosal/mercury-autism 
link. For years the Centers for Disease Control and Prevention, the 
American Academy of Pediatrics, the Children's Hospital of 
Philadelphia's Vaccine Education Center, the National Academy of 
Sciences, the Food and Drug Administration, and countless other 
prestigious organizations and scientists have said the data do not 
support mercury in vaccines as the cause of autism.

Now, with the mercury long out of vaccines, what is there left to 
say? Why won't the slandering of vaccines as the cause of autism stop?

There has always been a great deal of antipathy toward vaccines - in 
part because vaccines do have a tiny chance of causing death or other 
serious side-effects. Parents who have been through that hell have a 
hard time hearing or sending any other message other than "vaccines 
are bad." And those who made careers out of peddling the 
vaccine-autism link - in the face of a lack of evidence - have really 
been motivated by a distrust of medicine, science, government and 
experts, a distrust that has little to do with scientific studies or 
expert opinions. Even government officials have never really cared 
enough about public health to do much to counteract the incredible 
damage the autism-vaccine proponents have done. That is not 

Our nation is spending a fortune on plans to cope with the prospect 
of a bioterror attack. State, city and federal agencies are trying to 
figure a plan if avian flu mutates into a form in which it can start 
killing people. Hospital officials are worrying over how to cut back 
on preventable deaths in our hospitals and nursing homes. Those in 
charge of keeping disease transmission in hospitals, schools and 
public spaces to a minimum are fretting over what steps to take. The 
answer to every one of these challenges involves - vaccines.

This nation's future, its national security, the safety of its 
health-care institutions, and the safety of its citizens depends upon 
vaccination. It is way past time that message got heard by parents, 
teachers, nurses, doctors, hospital administrators, the media and 
politicians. If there has been a more harmful urban legend 
circulating in our society than the vaccine-autism link, it is hard 
to know what it might be. At a time when vaccines may be our last 
best hope in facing some of the greatest challenges we and our 
children face, this legend needs to be put to rest. Vaccination, not 
vaccine-bashing, is what this nation needs.

Contact Arthur Caplan at [log in to unmask]