So fetal tissue was involved in the development phase but is not used in the production phase?
Not exactly. The original line of cells in 1975 or so may have come from aborted fetal cells. Nothing since then, or that is what I understand. And it is unclear if the the fetal cells came from abortions or still born children. There were no babies aborted just to produce the vaccine which is often the what these stories seem to imply.