I looked up the new Pfizer vaccine and they don't use fetal cells:  https://www.nationalreview.com/corner/pfizer-covid-vaccine-not-created-with-fetal-cells/

Sean, a vaccine is made partially from a virus, so Confederate’s question is important.  
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Honestly, we need a good, orthodox, Catholic virologist to answer these scientific concerns.    

Call me simple, but it's clear to this simple Catholic that the use of a product predicated on the use of a deliberate killing of an innocent human life is morally wrong.
Much else is wrong with these vaccines and/or hydrogel patches imbedded with DNA or RNA. It may be that Holy God is protecting His children and warning us against putting these satanic, NWO, Bill Gates Trojan Horses into our bodies by the knowledge that babies were electively aborted in order to create them.

Refuted by this priest here:

https://cogforlife.org/wp-content/uploads/VaccineFrCopenhagen.pdf

This article also decimates the circuмstantial permissibility of remote indirect cooperation in evil argument as well:

“In determining the moral liceity of using vaccines derived from abortion, an assessment of cooperation with evil in terms of distance from the original abortion is a necessary but ultimately insufficient criterion because there is another distinct and more immediate category of sin involved. To conclude, as some have, that there is only mediate remote material cooperation in abortion by the vaccine recipient is a red herring. It shifts emphasis away from the specific moral character of possessing and using the cell line itself toward “historical association” with the original abortion, obscuring the central problem while even causing it to go unnamed. The recipient is an immediate participant in the commission of continuous theft of human remains obtained through deliberate killing, their desecration through exploitation and trafficking, as well as ultimate omission to respectfully bury them. While the original killing establishes the illicit character of using the remains, their possession and use becomes a distinct evil in itself, the circuмstances of which do not cease as a form of theft, desecration, exploitation, and refusal to bury, regardless of the consumer’s  in time from the abortion, or the number of cell divisions, or the merely sub-cellular fragmentary inclusion of the child’s DNA and protein in the final dose.

Two sanitizing mischaracterizations contribute to this unwarranted shift in emphasis away from immediate continuing theft toward “historic” completed abortion. Firstly, the broadness of labelling human remains obtained through violence as “illicit biological material” is not only insufficient but dehumanizing and offensive. Although the vast majority if not all of the cells currently used did not physically constitute part of the child’s original body, these cells still belong to the child. They are a living remnant of the child’s life in this world. If they are not the child’s cells then whose cell’s are they? Is it possible to stretch jargon so far as to say that these are no one’s cells? No person donating their tissue for cell culture and knowingly encountering the resultant cells in a lab would identify them as anything other than “my DNA, my cells.” The child has been silenced, the parents have forfeited by abortion any right of consent to respectful scientific use of the body, the scientists and patent holders have no right to possess or use the cells: these human remains belong to God, must be respectfully reposed, and it is not for Caesar to say otherwise.

Secondly, “historical distance” from the abortion does not distance us from the possession of something stolen. If I am the beneficiary of a violent bank robbery where the clerk was murdered to secure funds, my personal distance from the robbery does not make it licit to possess or spend those funds or even other monies made playing the stock market with them. If this is the case with lifeless currency, how much more with the body of an innocent human being. If a copyrighted film is captured, reproduced, and sold through the internet, it does not somehow become licit to possess and use it simply because it has been copied many times over from the original, even if I have provided the means of copying, storage, and playback. The copyright protected item is the original artistic creation. Our artist is the Divine Author of human nature who produces a unique biological and spiritual work in His own image and likeness. It is absurd to say to public consumers that everyone must indefinitely use stolen work to help lessen the likelihood of a potential future problem even though a perfectly fine substitute can be easily and ethically provided. How much more with cannibalizing human remains obtained through violence. No one is bound to participate in one sin in order to avoid another. It is never permissible to do evil for a good purpose.”

I don't buy the priest's logic that the cellular/DNA level is the same substance as the aborted child.  In my mind, it's arguable that the child's fetal tissue has undergone a substantial change and no longer exists.  
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The Church teaches that 15 minutes after we receive Holy Communion, that Our Lord's body no longer exists, as it has been dissolved, and we can eat food.  But doesn't Our Lord's DNA still exist in our bodies, according to the priest's logic?  Thus, we can never eat food again?  Of course, that's ridiculous.  Once something undergoes a substantial change, then the original thing no longer exists.  As I see it, it's arguable that a baby's body undergoes 1 substantial change, and possibly 3!
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1) fetal cells removed from the body.  Once a cell is removed from the body, it's no longer part of the human being.
2) those fetal cells mixed with a virus to create a new strain.  It could be argued that the virus absorbs these cells, so the fetal cells no longer exist.
3) the new virus is replicated many times.  This new substance is certainly not the original baby, even if the DNA is similar.  A copy is not the same thing as the original.

Keep reaching.

It’s basic philosophy

I’m not saying I disagree with the conclusion that using fetal cells is wrong.  I’m simply trying to understand the logic.  So far, none of the articles has satisfactorily explained the issue in the details required. 

The Church teaches that 15 minutes after we receive Holy Communion, that Our Lord's body no longer exists, as it has been dissolved, and we can eat food.  But doesn't Our Lord's DNA still exist in our bodies, according to the priest's logic? 

Hardly.  Christ's DNA was never actually in us, since that pertains to the accidents and not the substance of Our Lord's body.

I looked up the new Pfizer vaccine and they don't use fetal cells:  https://www.nationalreview.com/corner/pfizer-covid-vaccine-not-created-with-fetal-cells/

Yes, it does (and so does the Moderna one):

https://cruxnow.com/church-in-the-usa/2020/11/use-of-pfizer-moderna-covid-19-vaccines-is-morally-acceptable-say-bishops/

“They are not completely free from any connection to abortion, however, as both Pfizer and Moderna made use of a tainted cell line for one of the confirmatory lab tests of their products."