Vaccine manufacturers use cells from aborted human fetuses in vaccine production.
This claim conflates historical cell line derivation with vaccine contents. Two cell lines, HEK 293 (human embryonic kidney cells) and MRC-5 (Medical Research Council cells), were derived from fetal tissue in the 1960s and 1970s, decades before modern vaccines existed. These cells are used in laboratory research to test or manufacture certain vaccines (like some adenovirus vaccines and chickenpox vaccines), but no actual fetal tissue appears in the final vaccine product. The cells are cultured, then the culture is processed and purified to extract viral particles or proteins; the human cells are removed. Analogously, many medications used lab cells (Chinese hamster ovary cells, insect cells) in their development, but you don't ingest hamster cells in your medication. The source of the original cell lines is morally complex and worth discussing in bioethics contexts, but it does not mean that vaccines contain fetal tissue. Catholic bishops have reviewed the evidence and determined that using such vaccines is morally permissible when alternatives don't exist, precisely because no fetal tissue is in the final product. For transparency, manufacturers do list the cell lines used in development on package inserts, allowing informed decision-making without requiring scientific falsehood.