November 4, 2019
The bottom line: Vaccines do not cause autism. Despite claims to the contrary, more than 25 scientific studies conducted over decades show no connection between the measles-mumps-rubella (MMR) vaccine (or any other vaccine) and the neurological condition. However, physicians seeking to immunize patients to reduce the threat of a major measles outbreak fight an uphill battle against the debunked myth about vaccines and autism.
Physicians repeat it over and over: Vaccines like the measles-mumps-rubella (MMR) vaccine do not cause autism; they are safe and effective. Yet the decades-old false claim that vaccines do cause autism has convinced millions of parents not to give their children potentially lifesaving shots and could lead more to opt out, according to Texas physicians.
“There is no connection that we can find between vaccines and autism,” said Jennifer Shuford, MD, infectious disease medical officer for the Texas Department of State Health Services. “There’s been a lot of research that has looked at this question, because we want to make sure that something we are recommending for an entire population is not causing devastating health consequences.”
The Centers for Disease Control and Prevention recommends the MMR vaccine to protect children against measles, mumps, and rubella. Texas, however, is one of 16 states that permits exemptions based on philosophical beliefs, not only on medical reasons, from the vaccines required to enter school. Despite dozens of scientific studies showing no link between MMR and autism, antivaccine advocates have repeated the claim that a link exists, contributing to the spike in unvaccinated children since the exemption went into effect in 2003.
The MMR vaccine is a well-documented defense against infectious diseases including measles, reports the Texas Medical Association’s (TMA’s) Texas Medicine magazine. However, in 1998, British then-gastroenterologist Andrew Wakefield, MD, coauthored a study published in The Lancet claiming to have found a link between MMR and autism. The British Medical Journal later called Dr. Wakefield’s report an “elaborate fraud,” and The Lancet retracted the paper. It found Dr. Wakefield had skewed his research results, abused the children he was studying, and hid his financial reasons for the report. Since then more than 25 scientific studies have found no link between the vaccine and the disorder. (The United Kingdom has barred Andrew Wakefield from practicing medicine.)
Yet antivaccine advocates repeating the debunked claim have contributed to a drop in vaccination rates in the U.S. and Europe
Since 2003, Texas vaccination exemptions have soared more than 2,000% to 64,176 statewide. Yet the state’s overall exemption rate is 1.2%, meaning more than 98% of students statewide are vaccinated. Roughly 95% of people must be vaccinated in a region to preserve community immunity (sometimes called “herd immunity”), in which immunizing enough people in a group protects those who can’t get vaccinated.
Having more vaccine opt-outs in a local area, however, increases the likelihood of a disease outbreak, especially a highly contagious virus like measles.
A report by the Texas Department of State Health Services says 69 Texas accredited private K-12 schools have exemption rates in double digits. Those areas with higher exemption rates are more vulnerable to outbreak. “When about 95% of a population is covered by the vaccine, we won’t see ongoing transmission of measles in that community – it might spread to one other person, but then it’ll stop,” said Dr. Shuford. “That’s what we hope for when we look at vaccine campaigns for whole populations.”
Texas saw 21 measles cases in 2019 as of September, and doctors warn more cases are on the way. Three Texas counties – Harris, Tarrant, and Travis – were ranked among the top 25 counties nationwide considered most likely to see a measles outbreak, according to a May 2019 study by The University of Texas at Austin and Johns Hopkins University. Thus far in 2019, El Paso County was the only Texas county to have a measles outbreak – defined as three or more related cases.
“We see how devastating measles can be to people. It kills an enormous number of children around the world every year, so measles is dangerous; that is well documented,” said Dr. Shuford. “And that’s what we want to protect against.”
This release is part of a monthly TMA series raising awareness about vaccines and addressing common concerns about them.
TMA also highlighted contagious diseases that childhood and adult vaccinations can prevent, including measles, chickenpox and shingles, pertussis (whooping cough), and many others. Visit the TMA website to see efforts to raise immunization awareness and how doctors are fighting back against false claims that hamper immunizations.
TMA is the largest state medical society in the nation, representing nearly 53,000 physician and medical student members. It is located in Austin and has 110 component county medical societies around the state. TMA’s key objective since 1853 is to improve the health of all Texans.
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TMA Contacts: Brent Annear (512) 370-1381; cell: (512) 656-7320
Marcus Cooper (512) 370-1382; cell: (512) 650-5336
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