Shapiro vs RFK Jr: What’s In MMR?

Public records show the MMR’s rubella virus is grown in a human fetal-derived cell line, even as officials insist no “fetal tissue” is in the shot.

Story Highlights

FDA and medical sources confirm rubella for MMR is grown in WI-38 human fetal-derived cells.
Governor Josh Shapiro said “There is no fetal tissue in the MMR,” citing pediatric guidance.
Robert F. Kennedy Jr. highlighted the WI-38 origin and posted details on social media.
Experts say the final vaccine contains virus plus residual byproducts, not intact fetal tissue.

What sparked the clash between Shapiro and RFK Jr.

Pennsylvania Governor Josh Shapiro said “There is no fetal tissue in the MMR,” and linked to guidance from the American Academy of Pediatrics that says vaccines do not contain fetal cells. The guidance explains some vaccines use human cell cultures from the 1960s, but purification removes fetal tissue from the final product. Robert F. Kennedy Jr. answered online that the rubella strain used in MMR is grown on the WI-38 human cell line, which began with fetal lung tissue decades ago.

Kennedy’s framing centers on the production chain rather than the bottle on the clinic shelf. He points to the well-documented fact that rubella virus used for MMR is cultivated in WI-38 human diploid lung fibroblasts, a cell line that originated from fetal tissue in the 1960s. Shapiro’s message focuses on the end product that patients receive. He cites medical groups that say the finished vaccine does not contain intact fetal tissue or cells.

What the official documents and medical sources actually say

Food and Drug Administration labeling for Measles, Mumps, and Rubella Virus Vaccine Live (M-M-R II) states the rubella component is propagated in WI-38 human diploid lung fibroblasts. The Children’s Hospital of Philadelphia ingredient listing explains the vaccine can contain residual byproducts from cells used to grow the virus, including proteins from WI-38 human cells, along with other ingredients like neomycin. Independent explainers echo this: the rubella virus is grown in a fetal-derived cell line; the vial does not contain intact fetal tissue.

These statements can both be true at once. The manufacturing process relies on a line that began with fetal lung cells many decades ago. The final dose includes the weakened viruses and trace residuals from the growth process, not whole fetal tissue. That is why wording matters. Saying “grown using fetal-derived cells” fits the record. Saying “contains fetal tissue” blurs the line between the process and the product, which medical groups dispute.

Why this matters for ethics, faith, and informed consent

Religious and pro-life Americans care how products are made, not just what is in the bottle today. Medical sources acknowledge the WI-38 origin in fetal tissue from the 1960s, and they stress that no new abortions are needed for ongoing production. Many families weigh that history when making choices. Clear, plain language helps parents and faith leaders decide, and it avoids the sense that officials are hiding the ball with narrow, technical answers.

AI Fact Check; TRUE
– Emily Kopp's post highlights a discrepancy where Pennsylvania Gov. Josh Shapiro attributed one of two "measles-associated" deaths to lack of vaccination, but Lancaster County Coroner Steve Diamantoni determined the newborn died from a spleen laceration…

— Bill Heller (@noturbine) August 28, 2026

Precision also helps public health. When leaders deny any link to fetal cell lines, they lose trust with people who have read the label or seen credible summaries. When advocates claim “fetal tissue in the shot,” they overstate what the final dose contains. The strongest, most accurate summary is this: the MMR’s rubella component is produced using a human fetal-derived cell line from the 1960s; the finished vaccine does not contain intact fetal tissue, though residual byproducts can remain.

Bottom line for conservative readers

Parents deserve straight talk without word games. The record shows the rubella virus for MMR is grown in a human fetal-derived cell line, WI-38. That history raises real moral questions for pro-life families. At the same time, medical sources say the final shot does not include intact fetal tissue. Officials should respect conscience rights, present the facts plainly, and stop smearing good-faith concerns as “misinformation.” Trust grows when the government tells the whole truth, not just the part it prefers.