A major new study offers yet more evidence that the vaccine that protects against measles does not increase children’s risk of autism.
The study, conducted by researchers in Denmark and published this week in Annals of Internal Medicine, examined all children born in Denmark to Danish-born mothers from 1999 to 2010 ― 657,461 children.
“The study strongly supports that MMR vaccination does not increase the risk for autism, does not trigger autism in susceptible children, and is not associated with clustering of autism cases after vaccination,” the researchers wrote. “It adds to previous studies through significant additional statistical power.”
Among the research participants, 6,517 children were diagnosed with autism in the next decade during the study. But researchers found no increased risk for autism among those who received the MMR vaccine, which protects against measles, mumps and rubella, when compared with the children who did not receive immunization.
The researchers also found that children who might be considered high-risk, including those who had a sibling with autism, were not more likely to develop the disorder after receiving the vaccine.
The study was co-funded by the Danish Ministry of Health and Novo Nordisk Foundation, which is associated with a pharmaceutical company that does not manufacture the MMR vaccine.
The belief that the MMR vaccine increases the risk of autism stems from a debunked 1998 study based on just 12 patients and conducted by a doctor later found to have falsified data.
Though false, the belief has had real impact, fueling an international anti-vaxx movement that has contributed to numerous measles outbreaks in recent years.
An unvaccinated child vacationing with his parents in Costa Rica brought the first case of measles the country had witnessed since 2014. An outbreak of the disease last month prompted the governor of Washington to declare a state of emergency.
The World Health Organization identified vaccine hesitancy as one of 10 major threats to global health in 2019.
“The idea that vaccines cause autism is still around despite our original and other well-conducted studies,” Anders Hviid, an epidemiologist at the Staten Serum Institute and one of the study’s authors, told NPR. “Parents still encounter these claims on social media, by politicians, by celebrities, etc.”
Some conservative politicians in the United States have contributed to misinformation surrounding vaccines.
Texas state Rep. Bill Zedler (R), a major ally of Texans for Vaccine Choice, last week claimed the measles vaccine isn’t necessary because of the existence of antibiotics.
Antibiotics treat bacterial infections. Measles, however, is a highly contagious disease caused by a virus that can spread through the air.
There is no prescription medication that treats the disease, which can cause fever, runny nose and small red bumps over the entire body. In the worst cases, the disease can weaken the immune system, leading to complications such as pneumonia and encephalitis, and even to death.
The U.S. Centers for Disease Control and Prevention recommends children receive two doses of the MMR vaccine, first at 12 to 15 months of age and then at 4 to 6 years of age. Two doses of the vaccine are roughly 97 percent effective at preventing measles, according to the CDC.