The only vaccines that are made in human fetal cells (known as fetal cell lines) during their production process are chickenpox (varicella), rubella, hepatitis A, and the Johnson & Johnson COVID-19 vaccine (viral vector vaccine), in addition to one of the available rabies vaccines.

The viruses for these vaccines were grown in cells taken from elective terminations of pregnancies, which took place in the early 1960s. Since then, the cell lines for these vaccines have been maintained in the lab and no further sources of fetal cells are necessary to make these vaccines.

The reasons that fetal cells were originally used included: