Is the Vaccine-Autism Debate Finally Over?

A comprehensive study published in Pediatrics on September 13th has discredited, once again, the vaccine-autism link.  The Centers for Disease Control and Prevention called on 14 researchers to investigate the link between vaccines containing thimerosal, a mercury-containing preservative, and autism spectrum disorders. Their findings show that kids exposed to the preservative as babies or prenatally were not more likely to develop autism, a finding supported by numerous other studies. Will this finally put an end to the anti-science, anti-vaccination rhetoric? Don't hold your breath.

Because despite the overwhelming evidence to the contrary, one in four parents in the U.S. still believes that vaccination will raise their child's risk of developing autism. And it's not just concern; many parents are foregoing vaccines altogether. Lack of vaccination likely contributed to this past summer's whooping cough epidemic in California, which killed eight infants.  Intentionally unvaccinated school-age children also contributed to the 2008 measles resurgence.

How did the misinformation become so prevalent? The whole autism-vaccine link was put to speculation back in 1998, when Andrew Wakefield, a doctor in Britain, published an article showing that eight children developed autism-like symptoms after being vaccinated for measles, mumps and rubella (the MMR vaccine). The paper was published in the highly-repsected journal the Lancet, and it opened the floodgates for concerns over the causal link between vaccines and autism. Anectodal reports of children coming down autism symptoms shortly after vaccinations were widely publicized. Celebrities like Jenny McCarthy helped promote the idea that vaccines cause autism. Lawsuits were filed.

Yet the science refuting the shaky hypothesis started to emerge. Over a dozen epidemiological studies have failed to find a link between autism and vaccines. In May, Dr. Wakefield was found guilty of "serious professional misconduct," including taking blood samples for his study from children at his son's birthday party (generally a big no-no in the medical ethics community). His medical license was revoked. It also came to light that his original research was funded by lawyers for the parents suing the vaccine makers. Conflict of interest, anyone?

The final nail in the coffin came when the Lancet retracted Wakefield's original study after concluding that he conducted dishonest and unethical work.

The courts have also denied any claims of causality. On August 27th, a federal appeals court upheld a ruling that vaccines are not the cause of autism.

One study can't completely refute a hypothesis, but this new paper adds to the overwhelming, scientifically-credible research showing no link between autism and vaccination. Yet emotionally-charged misinformation is hard to rectify-- and so the debate isn't likely to end anytime soon.

Photo credit: Elton Lin