# The MMR vaccine contains tissue from aborted fetuses, listed openly in its own ingredients

**Verdict: Contradicted.** This is one of the most precisely constructed false claims in the corpus, and taking it apart requires conceding most of it. In an X post on 25 August 2026 the US health secretary wrote that the rubella virus in MMR-II is grown on a cultured cell line composed of lung tissue from an aborted three-month-old female embryo, that this line is listed as WI-38 human diploid lung fibroblasts in the ingredients, and that portions of those cells end up in each vial. The first two points are accurate and the ingredient listing is real. The last is not: the attenuated virus is extracted from the culture and purified, and no trace of the WI-38 cells remains in the finished vaccine. Snopes rated the claim false. The verdict here applies to that single clause about what is in the vial, not to the history of the cell line, which is real and is a fair subject for moral argument. What this file rates is the substitution of a false empirical claim for an ethical question that can actually be answered.

Category: Science, Space & Technology · Era: 2020s · First circulated: The underlying objection dates to the 1960s development of the WI-38 line; this particular formulation was made publicly on 30 April 2025 and again, in a much more precise version, on 25 August 2026 · Believed by: People with a sincere moral objection to abortion who want to know what they are consenting to, which is a reasonable thing to want to know. The claim travels because it appears to answer that question with a document, and because the part of it that is checkable checks out
URL: https://theconspiratory.com/theory/mmr-fetal-tissue-claim

## Summary
Almost everything in the claim is true, which is why it works. The rubella component of MMR-II really is grown using WI-38, a cell line really derived from lung tissue of a foetus aborted in Sweden in the early 1960s, and WI-38 really is named in the product's ingredient listing. The single false element is the conclusion: that portions of those cells therefore end up in each vial. They do not. The virus is grown in the culture, then extracted and purified, and no trace of the cells remains. Snopes rated the claim false on that basis. Meanwhile the wider context is not in dispute: the CDC recorded the worst US measles outbreak since 1991, with 2,777 cases from the start of 2026 to 20 August and 7% requiring hospitalisation. This file rates the claim about the vial's contents. It does not rate the moral question about the cell line's origin, which is genuine, is separable, and is the thing the false claim displaces.

## The claim
That the MMR vaccine contains material from aborted fetuses, such that anyone receiving it is injected with fetal tissue, and that this is documented in the vaccine's own ingredient list.

## Origin and timeline
- 1961: Leonard Hayflick and Paul Moorhead publish their work on the serial cultivation of human diploid cell strains, establishing that ordinary human cells divide a limited number of times before dying, a boundary that becomes known as the Hayflick limit. The finding makes a stable, finite human cell line valuable for growing viruses.
- 1962: A woman three months pregnant has a legal abortion in Sweden. As the author Meredith Wadman documents in The Vaccine Race, the foetus was not incinerated or buried; it was wrapped in sterile green cloth and sent to Hayflick, who isolated from its lung tissue the cell line designated WI-38. This is the event at the centre of the moral argument, and nothing in this file disputes that it happened.
- 1960s onward: WI-38 becomes the basis for producing vaccines against poliomyelitis, measles, mumps, rubella, varicella, adenovirus, rabies and hepatitis A. A 2024 obituary for Hayflick in the journal NPJ Aging estimates the number of people who have benefited over fifty years at several billion. No further abortions were required: the same 1960s line continued to be cultured.
- 2020-01-29: An article in the medical journal Vaccine sets out the production method plainly. The most common rubella vaccine strain, RA27/3, was extracted using explant liver culture and attenuated by passaging in human diploid fibroblasts, WI-38, at 30 and 35 degrees Celsius. Growing a virus in a cell culture is the step the later claim describes correctly.
- 2020-11: A BBC Future article on the cell line records that institutions otherwise opposed to abortion, including the Catholic Church, have publicly supported the use of vaccines manufactured this way where no alternative exists, while also expressing a need for alternative sources. The ethical question had already been asked, in public, and answered by the bodies whose members most needed an answer.
- 2025-04-30: At a NewsNation town hall with Chris Cuomo, the US health secretary says the MMR vaccine contains a lot of aborted fetus debris. This is the loose version of the claim: emotive, imprecise, and easy to dismiss.
- 2026: The CDC records the worst US measles outbreak since 1991: 2,777 cases from the beginning of 2026 to 20 August, 7% of them requiring hospitalisation, with three deaths reported in 2025 and none in 2026. Harvard Medical School notes that suppressing measles requires about 95% immunisation, that the national rate had fallen to 92% by 2023, and that it stood at 82% in the West Texas area where the 2025 outbreak began.
- 2026-08-25: Responding on X to Pennsylvania Governor Josh Shapiro, who had accused him of peddling vaccine conspiracy theories, the health secretary restates the claim in a far more precise form: that the rubella virus in MMR-II is grown on a cell line composed of lung tissue from an aborted three-month-old female embryo, that it is listed as WI-38 human diploid lung fibroblasts in the ingredients, and that portions of these cells end up in each vial.
- 2026-09-01: Snopes rates the claim false, on the specific ground that the vaccine does not contain fetal material. The virus is attenuated in the cells, then extracted and purified, removing all trace of WI-38.

## The evidence, claim by claim
- Claim: WI-38 is listed in the MMR-II ingredients, so the cells are in the product.
  Evidence: An ingredient listing of this kind records what was used in manufacture, not only what remains at the end. The rubella virus is grown in the WI-38 culture and then extracted and purified, a step that removes the cells; no trace of them appears in the finished vaccine. The listing is honest disclosure of the production method, and reading it as a contents label is the single move on which the entire claim depends.
- Claim: The cell line came from an aborted foetus, which the fact-checkers gloss over.
  Evidence: They do not, and neither does this file. WI-38 was isolated from the lung tissue of a foetus aborted legally in Sweden in 1962 and sent to Leonard Hayflick's laboratory. That is documented, uncontested, and recorded here in the timeline above. Establishing it does not establish anything about what the vial contains, which is a separate question with a separate answer.
- Claim: Vaccine production therefore creates an ongoing demand for aborted fetal tissue.
  Evidence: It has not. The same 1960s line has been cultured continuously, and vaccine development has not needed to take new cells from more recent abortions. WI-38 underlies vaccines for at least eight diseases, with a 2024 estimate in NPJ Aging putting the beneficiaries at several billion people over fifty years. Whatever one concludes morally, the object of that judgement is a single historical event, not a continuing practice.
- Claim: This is a religious objection that scientists refuse to engage with.
  Evidence: The engagement happened, publicly and some time ago. As the BBC reported in 2020, institutions otherwise opposed to abortion, the Catholic Church among them, have stated that using vaccines produced this way is acceptable where no alternative exists, while pressing for alternative sources to be developed. That is a considered answer to the real question, and it is available to anyone weighing it.
- Claim: Fact-checkers call the whole statement false, which is obviously unfair when so much of it is right.
  Evidence: That objection has force, and it is worth stating precisely rather than waving away. Of the claim's components, the growth medium, the origin of the line and the ingredient listing are all accurate. What was rated false is the conclusion drawn from them: that portions of the cells end up in each vial. A rating attaches to the claim being tested, and here that claim was about the contents of the vaccine.

## Why people believe it
- The checkable parts check out. Someone who looks up WI-38, finds it named in the ingredients and finds its 1962 origin has verified three separate assertions and been right every time, which is a powerful reason to trust the fourth.
- The moral concern underneath is real and is not a misunderstanding. A person who objects to abortion and wants to know whether a medical product is connected to one is asking a coherent question that deserves a straight answer.
- Ingredient lists are read as contents lists everywhere else in daily life, on food packaging above all, so applying that habit to a vaccine insert is an ordinary inference rather than a paranoid one.
- The 2026 formulation is markedly more precise than the 2025 one, and precision reads as expertise. A statement carrying a cell line designation, a tissue type and a temperature-controlled process sounds like someone who has done the reading.
- Institutional reassurance about vaccines has a mixed record on other questions, so an audience that has been told not to worry before may reasonably want to check this one themselves.

## Open questions
- Whether ingredient listings should distinguish more clearly between substances present in the finished product and materials used during manufacture, since the conflation of the two is doing all the work here.
- Whether alternative cell lines could replace WI-38 in rubella vaccine production, which is what the religious bodies that examined the question actually asked for, and what it would cost to do so.
- How much of the fall in US measles immunisation, from about 95% to 92% nationally by 2023 and to 82% in the area where the 2025 outbreak began, is attributable to claims of this kind rather than to access, cost or complacency.
- Whether a claim assembled this way, mostly accurate with one false conclusion, is best answered by a true-or-false rating at all, or whether the format itself hands the speaker the objection that the fact-check was unfair.

## Sources
- No, the MMR vaccine does not contain fetal tissue, despite RFK Jr.'s claim, Snopes (2026): https://www.snopes.com/fact-check/rfk-mmr-vaccine-fetal-tissue/
- The controversial cells that saved 10 million lives, BBC Future (2020): https://www.bbc.com/future/article/20201103-the-controversial-cells-that-saved-10-million-lives
- After 100s of millions of safe MMR shots, Trump baselessly said the vaccine is possibly 'quite lethal', PolitiFact (2026): https://politifact.com/factchecks/2026/aug/11/donald-trump/mmr-measles-vaccine-safety-cdc/
- Doctors don't inject kids with soda bottle's worth of vaccines. Trump's claim is Pants on Fire, PolitiFact (2026): https://politifact.com/factchecks/2026/aug/11/donald-trump/vaccine-soda-bottle-injection-children/
- RFK Jr. and the claim that vaccines are never tested against a control group, Snopes (2024): https://www.snopes.com/news/2024/02/27/rfk-vaccines-control-group/

Rated by The Conspiratory, a neutral, sourced encyclopedia of conspiracy theories. Full page: https://theconspiratory.com/theory/mmr-fetal-tissue-claim