On April 30, 2025, the NewsNation news network conducted a televised town hall featuring presenter Chris Cuomo and U.S. Secretary of Health Robert F. Kennedy Jr., among other guests. During the broadcast, Kennedy claimed that the vaccine used against measles, mumps and rubella contained "a lot of aborted fetus debris."
When asked how he would respond to accusations that he was now encouraging people to get vaccinated against measles, to fight an ongoing outbreak of the disease, despite urging people not to get vaccinated during the COVID-19 pandemic, the health secretary said (starting at the 1:08 mark) that there should be options for those who refuse the jab (emphasis ours):
Now there are populations in our country, like the Mennonites in Texas, who were most afflicted, and they have religious objections to vaccination because the MMR vaccine contains a lot of aborted fetus debris and DNA particles. So they don't want to take it. So we ought to be able to take care of those populations when they get sick, and that's one of the things that CDC has not done. CDC has said that the only thing that we have is vaccination. There's all kind of treatments when people do get sick, and those people should be treated with compassion, I'll say, and we ought to have good treatments for them, and that's what we're developing at CDC right now.
The claim spread widely online following the town hall. For example, one X user echoed Kennedy, saying (archived): "Finally, the truth is coming out about the symbiotic relationship between the vaccine and abortion industries."
However, the health secretary's claim that the vaccine contains fetal material from abortions was incorrect. Therefore, we have rated the claim false.
The 2025 measles outbreak
It is true that, in 2025, the U.S. was seeing its worst outbreak of measles since 2019, according to the Centers for Disease Control and Prevention, with 1,001 cases as of May 8, 2025, 13% of which required hospitalization. The CDC also said that, as of this writing, three people had died of the disease in 2025.
(CDC)
Measles is a highly contagious disease that requires 95% of the population to be immunized to prevent its spread, according to Harvard Medical School. For years, the country was able to prevent new cases by keeping the vaccination rates at or above 95%. However, in more recent years, the vaccination rate began to fall. It was at 92% in 2023 and at 82% in the area where the 2025 outbreak started in West Texas, also according to Harvard Medical School. Experts have long identified disinformation and misinformation as key forces causing fears about the safety of the MMR vaccine and others, and, as Snopes reported in February 2024 and in May 2017, Kennedy has been a prominent voice in promulgating false claims about vaccines.
For full immunization, the schedule calls for two doses of the MMR vaccine, according to the CDC. Most people who were infected in the 2025 measles outbreak were either unvaccinated, had an unknown vaccination status or had received only one of the two doses, according to Harvard Medical School.
False claims about the MMR vaccine
The MMR vaccine has long been the target of false claims. For example, a now-debunked article, reported on by Snopes in January 2019, succeeded in convincing many concerned parents that a mercury-based preservative known as thimerosal, which some vaccines and other injections used to contain, was responsible for an increase in autism rates. While it is true that autism diagnoses have continued to increase in the U.S., it is not for this reason. In fact, childhood vaccines no longer contain thimerosal.
The combined MMR jab contains three live attenuated viruses. These versions of the viruses are too weak to cause an infection but are strong enough to provoke an immune reaction in which the body produces specific antibodies to fight the viruses if the person is exposed to them later.
The claim that the MMR vaccine contains fetal material stems from a misunderstanding of how the rubella attenuated virus is produced. According to an article that appeared in the Jan. 29, 2020, issue of the medical journal Vaccine, the most common rubella strain used in vaccines is attenuated in a cell culture that uses the specific cell line WI-38:
The most commonly used vaccine strain for the rubella virus is attenuated strain RA27/3, which was extracted using explant liver culture and attenuated by passaging in human diploid fibroblasts (WI-38), at temperatures of 30 °C and 35 °C.
The cell line WI-38 was isolated "from the lung tissue of a 3-month-old, female, embryo," according to the description of a website that commercializes the cells for use in vaccine development. eonard Hayflick, a U.S. scientist, isolated the cells from the embryo of a legal abortion in Sweden in the
The 'Hayflick cells', WI-38, have been the basis for producing vaccines for poliomyelitis, measles, mumps, rubella, varicella, adenovirus, rabies, and hepatitis A. Over the last 50 years, the number of people benefiting from these vaccines has been estimated to be several billion worldwide.
However, vaccine development has not needed to take new cells from more recent abortions. Further, while vaccine developers do attenuate the virus in the cells, they later extract it and purify it, removing all trace of WI-38 cells. In sum, no trace of the cells appears in the vaccine.