The Centers for Disease Control and Prevention is planning to conduct a large-scale study to re-examine whether there is a connection between vaccines and autism, federal officials said Friday.
Dozens of scientific studies have failed to find evidence of a link. But the C.D.C. now falls under the purview of Health and Human Services Secretary Robert F. Kennedy Jr., who has long expressed skepticism about the safety of vaccines and has vowed to revisit the data.
“As President Trump said in his Joint Address to Congress, the rate of autism in American children has skyrocketed. C.D.C. will leave no stone unturned in its mission to figure out what exactly is happening,” Andrew Nixon, a spokesman for the Department of Health and Human Services, said in a statement Friday.
Mr. Nixon did not offer details about the scope or methods of the project. News of the study was first reported Friday morning by Reuters.
In pursuing the study, the C.D.C. is defying the wishes of the chairman of the Senate Health Committee, Senator Bill Cassidy, who said this week that further research into any supposed link between vaccines and autism would be a waste of money and a distraction from research that might shed light on the “true reason” for a rise in autism rates.
“It’s been exhaustively studied,” Mr. Cassidy, a doctor, said during the confirmation hearing for Dr. Jay Bhattacharya, President Trump’s nominee to lead the National Institutes of Health. “The more we pretend like this is an issue, the more we will have children dying from vaccine-preventable diseases.”
While Dr. Bhattacharya said he is “convinced” from the existing research that there is no link between vaccines and autism, he suggested more research might assuage the fears of nervous parents. Mr. Kennedy’s backers, and allies of his “Make America Healthy Again” movement, lauded the administration’s decision.
“Both Trump and Kennedy are keeping their word,” said Zen Honeycutt, founder of the nonprofit Moms Across America. “We wish that the previous administration had made health and the autism epidemic a priority.”
The news of the planned C.D.C. study comes in the midst of a rapidly spreading measles outbreak in West Texas, driven by low vaccination rates, that has infected nearly 200 people and killed two. Last year, about 82 percent of the kindergarten population in the county most affected had received the measles vaccine, far below the 95 percent needed to stave off outbreaks. According to Texas health officials, 80 of those infected were unvaccinated and 113 had “unknown vaccination status.”
Asked in an interview about the C.D.C.’s plans to re-examine whether autism is connected to vaccination, Xavier Becerra, health secretary to President Joseph R. Biden Jr., said, “All I’ll say is that C.D.C. can do many things. They can walk and chew gum, but I would hope C.D.C. is being used to help us get a grip on measles before another life needlessly dies, perishes.”
The rate of autism diagnoses in the United States is undeniably on the rise. About 1 in 36 children have one, according to data the C.D.C. collected recently from 11 states, compared with 1 in 150 children in 2000. Researchers attribute most of the surge to increased awareness of the disorder and changes in how it is classified by medical professionals. But scientists say there are other factors, genetic and environmental, that could be playing a role, too.
“There are so many promising leads for the cause or causes of autism,” Dr. Paul Offit, a pediatrician specializing in infectious diseases at the Children’s Hospital of Philadelphia, said in an email Friday. “Vaccines aren’t one of them. Given that there are limited resources from the C.D.C., this is a sad day for children with autism.”
Like Mr. Kennedy, Mr. Trump has long espoused the idea that vaccines are somehow linked to rising rates of autism; he first raised the idea in 2007 and came back to it as a presidential candidate in 2015. He has also said he would support Mr. Kennedy re-examining the issue, most recently citing the rate of autism diagnoses during his address to Congress on Tuesday.
“We’re going to find out what it is, and there’s nobody better than Bobby and all of the people that are working with you,” he said. “Bobby, good luck. It’s a very important job.”
Mr. Kennedy won Senate confirmation as health secretary by the narrowest of margins. In the end, he prevailed largely by winning over Mr. Cassidy, a Republican of Louisiana, who specialized in liver disease as a doctor and strong supporter of vaccines. During the second day of the confirmation hearings, Senator Cassidy expressed deep concern about Mr. Kennedy’s past questioning of vaccines, and he cited a study of 1.2 million children had found no connection between vaccines and autism.
Mr. Kennedy shot back, saying a new study “showed the opposite.” A New York Times review of that study found that it was financed, authored, and published by a network of vaccine skeptics close to Mr. Kennedy. When the study was rejected by various mainstream medical journals, Andrew Wakefield, the author of a now-retracted 1998 study linking vaccines to autism, helped it find a home in a journal published by several vaccine critics.
After his confirmation, Mr. Kennedy’s first speech to his staff included a pledge to study the rise in chronic diseases in the United States, including with a review of the vaccine schedule, or suite of immunizations given to young children.
Christina Jewett contributed reporting.