US Health secretary Kennedy revives misleading claims of 'fetal debris' in measles shots

Reuters

01-05-2025

WASHINGTON, May 1 (Reuters) - U.S. health secretary Robert F. Kennedy Jr. reprised various misleading claims about vaccines this week, including that the measles vaccine contains cells from aborted fetuses and the mumps vaccination does not work.
Kennedy's comments come as the U.S. battles one of its worst outbreaks of measles in 25 years. Scientists have warned that the U.S. is at a tipping point for the return of endemic measles, declared eradicated nationally in 2000, and say U.S. public health officials like Kennedy should provide urgent endorsement for highly effective vaccines.
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Two children have died and hundreds more have been infected in the outbreak in Texas, which is centered in a Mennonite community and has spread to neighboring states, including New Mexico, Oklahoma, and Kansas.
Kennedy, who became the nation's top health official in February, has for decades helped sow doubts regarding the safety and efficacy of vaccines, contributing to a decline in vaccination rates.
Kennedy says he is not opposed to vaccines, but has begun to revive some of the unproven or debunked theories he promoted as a lawyer and public figure, now from his perch at the U.S. Health and Human Services Department.
"There are populations in our country, like the Mennonites in Texas, (who) were most afflicted, and they have religious objections to the vaccination, because the MMR vaccine contains a lot of aborted fetus debris and DNA particles, so they don't want to take it," he said in a News Nation interview on Wednesday.
Kennedy was referring to the combined Measles, Mumps and Rubella vaccine. The vaccines do not contain "fetal debris" from abortions or intact fetal cells, vaccine experts said.
The rubella portion of the vaccine is produced from a fetal cell line originating from an abortion that took place in the 1960s. The MMR vaccine does not contain the cells in its final form.
The cells are derived from fetal cells that have been replicated over decades in test tubes in laboratory settings, thousands of times removed from the original ones.
"The virus is grown in these cells, then this virus is purified, meaning everything other than the virus is filtered out, and all that's left is this attenuated virus that can't make you sick," said Dr. Miriam Laufer, Interim Director of the Center for Vaccine Development and Global Health at the University of Maryland.
According to a fact sheet on how vaccines are made from the Children's Hospital of Philadelphia at the University of Pennsylvania, the amount of DNA involved in final vaccine preparation is minimal; billionths or trillionths of a gram.
"While the final vaccines do not contain intact fetal cells, they may contain trace amounts of cell-derived materials, such as fragments of DNA," said Dr. Paulo Verardi, Professor of Virology and Vaccinology and the University of Connecticut.
The Department of Health and Human Services did not respond to a request for comment.
Kennedy also said this week that the mumps portion of the vaccine does not work and that there were safety concerns over it.
"The problem is really with the mumps portion of the vaccine and the combination. That combination was never safety tested," he said on Monday at a live televised town hall event hosted by TV host Dr. Phil.
Two doses of the MMR vaccine provide around 86% protection against mumps, according to the U.S. Centers for Disease Control and Prevention.
While it is true that vaccine protection can wane over time, the rate varies depending on the disease and vaccine, Verardi and other vaccine experts said.
"For mumps in particular, immunity can decline, so adults vaccinated in childhood may become susceptible again. Still, vaccinated individuals generally experience a milder illness if infected, which is still a key benefit of vaccination," he said.
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Ahmed Aboulenein
Thomson Reuters
Washington-based correspondent covering U.S. healthcare and pharmaceutical policy with a focus on the Department of Health and Human Services and the agencies it oversees such as the Food and Drug Administration, previously based in Iraq and Egypt.
Nancy Lapid
Thomson Reuters
Nancy has been a health news reporter and editor at Reuters for more than a decade, covering important medical research advances. She is the author of our twice-a-week Reuters Health Rounds newsletter.