The presidential candidates running for the White House have uttered a range of outlandish remarks during this election cycle, and many pertaining to the subject of public health. Some made by Dr. Ben Carson and Donald Trump, in particular, ignited controversy on a long-settled issue but one that science deniers continue to raise: vaccine and autism in children.
At the time, a wealth of studies had already led scientists and researchers to disprove any claimed links between the two. But a new study published in the Journal of the American Medical Association again shows that there is no link between vaccines and the condition.
The study looked at roughly 96,000 children with older siblings. Of this group, nearly all of the children with both affected and unaffected older siblings had measles-mumps-rubella (MMR) vaccinations between the ages two and five. Yet only about 2 percent of the children had an older sibling with an autism spectrum disorder (ASD), while only about 1 percent had ASD themselves.
From these findings, the study's team concluded that there was no link between MMR vaccine and autism at any age, even among those children who had affected older siblings and thus a higher genetic predisposition for ASD.
During a GOP presidential debate in September 2015, Dr. Carson, a retired neurosurgeon, commented upon Mr. Trump's previous remarks that certain vaccines, such as the MMR vaccine, lead to diagnoses of autism.
Supporters of this foolish belief cited a few studies to defend the possibility of an autism-vaccine link. One study published in the Lancet in 1998 (and later retracted) hypothesized that the combined effects of the three viruses -- measles, mumps and rubella -- in the MMR vaccine could lead to autism.
"This was something that was spread widely 15 or 20 years ago," Dr. Carson said of the vaccine-autism link theory, "and it has not been adequately, you know, revealed to the public what's actually going on."
Carson's statement shocked many experts on the subject and oppose the findings of many well-known and respected health authorities. The U.S. Department of Health and Human Services, the American Academy of Pediatrics and the CDC have all dismissed the claim of a link between MMR vaccines and autism.
"Vaccines are very important," Dr. Carson said. "Certain ones. The ones that would prevent death or crippling. There are others, there are a multitude of vaccines which probably don't fit in that category, and there should be some discretion in those cases."
Dr. Carson defended his stance of a possible link by implying that many vaccines given to children simply aren't necessary. But many groups have made lists of diseases they recommend children receive vaccine shots for. The CDC lists 15 infectious diseases -- among them measles, mumps and rubella -- as reasons for children to receive vaccine shots.
Yet despite warnings, the growing belief that MMR vaccines lead to autism may help explain a recent 2015 measles outbreak in California, where dozens of children at Disney theme parks got sick from the measles. Anti-vaccine movements may also explain why almost 200 Americans caught the disease last year, as measles was declared eradicated in the year 2000.
Rotavirus, also listed on the CDC's vaccine list, took the lives of over 400,000 children around the world younger than 5 years old, in 2008. Other vaccinated diseases may lead to severe problems other than death. Mumps, for example, could lead to deafness and sterility in both genders if not treated correctly in childhood.
Speaking with Politifact.com about Dr. Carson's comments, Dr. Adam Lauring gives a possible reason why anti-vaccine beliefs such as his and Trump's persist: "Because we don't see many of these diseases anymore, they are almost perceived as inconveniences. But fact is, people do die of these diseases and we have forgotten that because we haven't seen them."