More than 880 measles cases have been reported in the U.S. since February, including at least 660 in Texas, amid rising vaccine hesitancy fueled by inflammatory claims from Health and Human Services Secretary Robert F. Kennedy Jr., who recently asserted the MMR vaccine contains "aborted fetus debris."
Kennedy's comments, made during a NewsNation town hall focused on Donald Trump's first 100 days back in office, referenced religious vaccine objections among Texas Mennonite communities. "There are populations like the Mennonites in Texas who are most afflicted, and they have religious objections to the vaccination because the MMR vaccine contains a lot of aborted fetus debris and DNA particles," Kennedy stated.
Public health experts immediately disputed the claim. "Vaccines do not contain aborted fetuses, fetal cells, fetal DNA, or fetal debris," the Children's Hospital of Philadelphia said in response.
Kennedy's remarks, and broader statements from HHS, have escalated concerns among vaccine researchers, who argue the administration is eroding public trust in well-established immunization programs amid a deadly resurgence of a once-contained virus.
"Instead of just an anti-vaccine activist ... saying this stuff, now the federal government, HHS and FDA is now saying this stuff. That matters," said David Gorski, professor at Wayne State University School of Medicine and managing editor of Science-Based Medicine.
Kennedy's claim refers to a long-standing misconception tied to the use of cell lines developed decades ago from elective abortions in the 1960s and 1970s. These cell lines-such as HEK293 and PER.C6-are used to grow weakened viruses during vaccine production. But according to experts, these lines do not constitute fetal tissue, and the final vaccines are purified, containing no original DNA, tissue, or cells.
The controversy follows additional actions by HHS that have rattled vaccine developers. The agency announced plans to mandate placebo-controlled trials for all new vaccines, including those similar to long-standing ones like MMR. "All new vaccines will undergo safety testing in placebo-controlled trials prior to licensure-a radical departure from past practices," an HHS spokesperson told The Washington Post.
Critics argue such trials would be both unethical and impractical for diseases like measles, for which effective vaccines already exist. "No institutional review board at any academic center would ever accept that-so he's asking what personal injury lawyer invariably asks for, which is the impossible to be done," said Dr. Paul Offit, director of the Vaccine Education Center at Children's Hospital of Philadelphia.
Offit further warned that Kennedy's approach could destabilize the already fragile vaccine market. "It's his goal to even further lessen trust in vaccines and make it onerous enough for manufacturers that they will abandon it," he said.
The administration's scrutiny also appears focused on Covid-19 vaccine development. According to the Guardian, HHS recently shut down vaccine safety studies targeting special populations such as pregnant women and required that all mRNA-related grant proposals be flagged to Kennedy's office. In a statement, the department said: "The Covid-19 pandemic is over, and HHS will no longer waste billions of taxpayer dollars responding to a non-existent pandemic that Americans moved on from years ago."
Meanwhile, the FDA has delayed the approval of Novavax's new Covid-19 booster. A political appointee known to be vaccine-skeptical is reportedly reviewing the application. Novavax stated that the FDA has demanded a clinical trial as part of its post-approval surveillance. FDA Commissioner Marty Makary added to the confusion by referring to the routine strain update as a "new" product-raising concerns that updated shots might face burdensome regulatory requirements.
Kennedy, who previously ran a nonprofit known for spreading vaccine misinformation, has denied being anti-vaccine. "Secretary Kennedy is not anti-vaccine-he is pro-safety, pro-transparency, and pro-accountability," HHS said in a statement.
Kennedy's past claims, including that vaccines cause "autoimmune injuries and allergic injuries and neurodevelopmental injuries" with "long diagnostic horizons," continue to circulate widely. His advice to "do your own research" has become shorthand for misinformation-fueled distrust, say experts.
