According to the Centers for Disease Control and Prevention (“CDC”), measles was eliminated in the US in 2000. But its been creeping back. Between 2000 and 2010, the US averaged roughly 60 cases of the measles per year. Last year, however, the CDC reported 644 cases. And as of January 29, 84 people in 14 states have been reported as having measles, said Anne Schuchat, the head of the National Center for Immunization and Respiratory Diseases. Most of these cases – over 70 people – are linked to the outbreak at Disneyland. This measles outbreak at the Happiest Place on Earth is the legacy of anti-vaccine fear mongering and misinformation.
We’ve seen this story play out before. In 1988, for example, measles cases were estimated to be fewer than 10,000 a year. There was talk within the medical community about eradicating the disease – a remarkable accomplishment given that, in the late 1950’s, there were nearly 4 million cases a year and over 90% of the population was believed to be exposed in their lifetimes. Then something happened. From 1989-1991 measles made a comeback.
More than 55,00 cases were reported in that time period. The 1989-1991 measles epidemic, which resulted in 123 deaths and roughly 11,000 hospitalizations, was largely the result of under-immunization in preschool children and unacceptably poor access to health care. It is an illustrative example of the seriousness of the disease, and the fact that failure to fully vaccinate our children is extremely dangerous. The most recent outbreak is illustrative of that too. But in many ways it is more insidious, as it is solely the product of arrogant and foolish parental decisions.
The Disneyland outbreak is not the result of poor access to health care, nor is it “a problem of the measles vaccine not working. This is a problem of the measles vaccine not being used,” said Schuchat, the head of the National Center for Immunization and Respiratory Diseases. In other words, this outbreak is about people choosing not to vaccinate their children against the measles.
Some parents have avoided vaccinating their children out of a concern that vaccines are linked to neurological injury, and specifically to the neurological disorder autism (now referred to as autism spectrum disorder (ASD)). The primary argument made by “anti-vaccinationists” for an association between vaccines in general, the MMR (measles, mumps, and rubella) vaccine, or thimerosal (a mercury-based preservative in vaccines) and ASD is that the rate of diagnosis of ASD has increased dramatically at the same time that the number of vaccines routinely given to children has increased. Today, for example, one in every 150 children has been diagnosed on the autism spectrum; 20 years ago that statistic was one in 10,000. This, anti-vaccinationists say, is evidence of harm.
The logical fallacy within this argument should be immediately clear. Correlation does not imply causation, and simply because the rate of diagnosis of ASD has been increasing alongside increased vaccination rates does not mean that there is a cause-and-effect relationship. If this argument was all the anti-vaccinationists were relying upon, it would be hard to explain why this controversy has gotten such an ideological foothold. What else is going on? A series of questionable research “studies.”
The vaccine-autism saga began in 1998, when British gastroenterologist Andrew Wakefield and his colleagues published an article in The Lancet purporting to uncover a shocking cause of autism. Wakefield did intestinal biopsies via colonoscopy on 12 children with intestinal symptoms and developmental disorders, 10 of whom were autistic, and found a pattern of intestinal inflammation, which he pinned on the MMR vaccine. The published paper stated clearly: “We did not prove an association between measles, mumps, and rubella vaccine and the syndrome described.” But despite this disclaimer, Wakefield immediately held a press conference and articulated a specific theory of how the MMR vaccine could trigger autism: the inflamed intestines, he argued, released toxins in the bloodstream (like a poison), which then travelled to the brain.
Wakefield’s study has been subsequently discredited on a number of levels. First, attempts to replicate it all failed. Second, it was later uncovered that Wakefield had undisclosed conflicts of interest: (1) he had a pending patent application for a replacement MMR vaccine; and (2) he was being paid by an attorney (nearly half a million pounds plus expenses) to perform research to find a justification for a class action suit against MMR manufacturers. The children of the attorney’s clients were referred to Wakefield for the study, and 11 of his 12 subjects were eventually litigants.
Soon Wakefield’s credibility started to dissolve. The Lancet retracted his paper and its editor, Richard Horton, described the paper as “fatally flawed” and apologized for publishing it. Wakefield was dragged in front of the General Medical Council for charges of scientific misconduct. And of Wakefield’s 12 co-authors, 10 later issued a joint-retraction:
We wish to make it clear that in this paper no causal link was established between (the) vaccine and autism, as the data were insufficient. However the possibility of such a link was raised, and consequent events have had major events for public health. In view of this, we consider now is the appropriate time that we should together formally retract the interpretation placed upon these findings in the paper, according to precedent.
Here’s the more important point, however: even if Wakefield’s data had been right, it wouldn’t have been good science. To demonstrate a link between intestinal inflammation and autism, you would need to compare the rate of inflammation in autistic children to the rate of inflammation in non-autistic children (the controls). But Wakefield used no controls. And to implicate the MMR vaccine, you would need to demonstrate that the rate of autism was greater in children who got the vaccine and verify that autism developed after the shot. Wakefield made no attempt to do that.
Contrary to Wakefield’s assertions, a mountain of scientific research has demonstrated that vaccines are safe and effective, and that they are not linked to neurodevelopmental disorders. A recent meta-analysis, for example, found the following:
Five cohort studies involving 1,256,407 children, and five case-controlled studies involving 99,200 children were included in this analysis. The cohort data revealed no relationship between vaccination or autism (OR: 0.99; 95% CI 0.92 to 1.06) or ASD (OR: 0.91; 95% CI 0.68 to 1.20), or MMR (OR: 0.84; 95% CI: 0.70 to 1.01), or thimerosal (OR: 1.00; 95% CI: 0.77 to 1.31), or mercury (Hg) (OR: 1.00; 95% CI: 0.93 to 1.07). Similarly, the case-controlled data found no evidence for increased risk of developing autism or ASD following MMR, Hg, or thimerosal exposure when grouped by condition (OR: 0.90, 95% CI: 0.83 to 0.98; p = 0.02) or grouped by exposure type (OR: 0.85, 95% CI: 0.76 to 0.95, p = 0.01).
(Note: “OR” stands for odds ratio. Here, OR measures the difference in risk for autism between two groups – e.g. those who received the MMR vaccine versus those who did not. An odds ratio of 1.00 means that there is no difference in risk; numbers below 1.00 indicate decreased risk; and those above 1.00 indicate increased risk. “CI” stands for confidence interval, and “95% CI” means that, with 95 percent confidence, the true difference falls within the range of values given.)
The authors couldn’t have been clearer in their over-arching conclusion: “Findings of this meta-analysis suggest that vaccinations are not associated with the development of autism or autism spectrum disorder.” Period.
The fact of the matter is that vaccines are safe and effective. In fact, you are more than 22 times more likely to get the measles if you are unvaccinated than if you are vaccinated. And throughout history, vaccines have saved millions of lives. That’s not mere conjecture.
Recently, researchers from various universities in the US examined case reports from before and after the point in time when specific vaccines became commercially available, and they did it all the way back to 1888 (you read that correctly). The researchers reviewed nearly 88 million reported individual cases, and were able to conclude that since 1924:
Assuming that the difference between incidence rates before and after vaccine licensure for these diseases was attributable solely to vaccination programs, we estimate that a total of 103.1 million cases of these contagious diseases have been prevented since 1924 on the basis of median weekly prevaccine incidence rates.
The CDC did a similar study in 2010. The CDC compared the annual morbidity rates in the 20th century for 15 of some of the most common infectious diseases; that is, the most common before the introduction of vaccines. The dramatic impact of vaccinations on Americans’ health is illustrated in an infographic compiled by designer Leon Farrant:
This is what vaccines prevent. This is what will come back as vaccination rates fall.
A risk free life is not possible. Every year in America, thousands of people are killed by the same seat belts and airbags that are meant to protect them. But we continue to use them in the knowledge that they save far more lives than they harm. This is the truth about vaccines. In rare cases some children may have a harmful response to an immunization, and in exceedingly rare cases the reaction and harm may be severe. The alternative – not immunizing children – is much, much worse to society. Being unvaccinated not only places the individual in jeopardy, it carries with it the risk that others may suffer. Difficult decisions need to be made. But we should be clear about one thing: there is no duty to respect a foolish position.