How the question arose
The question of whether there was an ethical problem with any of the vaccines, arose from a short video about the Oxford-AstraZeneca vaccine a few months ago where claims were made about some of the individual terms used on the packaging of the vaccine and in an experiment.
There were a number of misunderstandings, one of which was that the Oxford-AstraZeneca vaccine ‘definitely’ had the lung tissue of an aborted male foetus in it and that you would be injected with fragments of it if you had that vaccine. You will be relieved to know that it does not, and you wouldn’t be. However, it was shared widely on social media, and as a result, many believed it to be true.
Some are also under the misapprehension that babies are currently being aborted and used in the manufacture of vaccines because, they believe, they would have to be currently aborted to get live cells. However, that is not the case, as cell lines are already ‘live’ cells.
So, fortunately, neither of the above scenarios is true.
It may be helpful at this point to explain what cell lines are, and how they are generated:
Cell lines originate from a cell or a group of cells isolated from tissue and grown in conditions that support their continued multiplication. They multiply very rapidly, producing vast numbers of more ‘live’ cells. They can continue to do so for many decades, even indefinitely.
They are well characterised and standardised for medical and scientific use.
The misunderstanding about the Oxford-AstraZeneca vaccine arose partly as the cell line noticed in an experiment (MRC-5) was not in fact used in the vaccine, and was only used indirectly in a preliminary experiment.
That cell line would not have originated from an elective abortion, since abortion was illegal at that time (1966), unless it was to save the life of the woman.
No original foetal cells would have been present in the experiment, since that cell line was generated about 55 years ago.
However, a different cell line was used in generating that vaccine; and even although the video gave wrong information, it highlighted the issue that some vaccines use cell lines, which may cause an ethical issue.
But even then, all is not as it seems…
mRNA vaccines and cell lines
First, two of the three COVID-19 vaccines currently approved by the UK Government are the two mRNA vaccines, Pfizer-BioNTech and Moderna. These do not use any cells or cell lines at all in vaccine production; but rather are made directly from a DNA template which arranges nucleotides in the right order. They have a wonderful simplicity, as discussed further in the question: Can the vaccine alter or affect your DNA? [link to above question]
No cells, human or otherwise, are in these mRNA vaccines.
Cells from the HEK293 cell line were sometimes used in tests following production of the vaccine. Some are therefore concerned that the vaccine would not have been released for public use without the ‘post-production’ use of HEK293 cells.
However, this is not the case with mRNA vaccines. The crucial tests – for example, whether serum from people who had been vaccinated will ‘neutralise’ (1) the real SARS-CoV-2 virus  or (2) ‘variants of concern,’  use the real virus itself, or a modified variant of the real virus. These experiments do not use HEK293 cells.
On the other hand, serum from people who had been vaccinated was also tested against what are called ‘pseudoviruses.’ These use a completely different virus (e.g. VSV), which has segments from minor variants of the real virus attached to it. These tests were carried out to provide an indication of how broad the effectiveness of the vaccine might be.  HEK293 cells were used in this. However, these experiments were not required for the vaccine to be released for public use.
DNA viral vector vaccines and cell lines
With the Oxford-AstraZeneca vaccine, there is more direct involvement with the HEK293 cell line, as the vaccine is cultured in HEK293 cells (rather like flu vaccines may be incubated in chicken eggs).
The vaccine is then very highly purified, removing all trace of HEK293 cells, before the vaccine is finalised. HEK293 cells are also used in the post-production stage for testing.
So, what is the HEK293 cell line?
The HEK293 cell line was established about five decades ago. It was originally derived from foetal kidney cells obtained from a single foetus in 1972 in the Netherlands by Professor Alex Van der Eb at the University of Leiden.
The cell line was created a year later, in January 1973, by Professor (then Dr.) Frank Graham,  who was investigating cancer and hoped to use the cell line for that purpose.
But what was the source of the cell line?
We tend to understand terminology through the lens of the way it is used in the times we live in, unless otherwise indicated. For many years, it has therefore automatically been assumed that the HEK293 cell line came not just from a single ‘abortion,’ but from a voluntary, elective abortion.
But the term ‘abortion’ was also used to describe ‘therapeutic abortions’ which would save a woman’s life, or to save them from serious harm. It was also used to cover ‘spontaneous abortions’ - the professional terminology for miscarriage used at the time in the medical and scientific community.
Professor Frank Graham, a researcher in Professor Van der Eb’s laboratory at the University of Leiden in the Netherlands at the time, explains very clearly that:
“Abortion was illegal in the Netherlands until 1984 except to save the life of the mother. Consequently, I have always assumed that the HEK cells used by the Leiden lab must have derived from a therapeutic abortion.” 
And since the University Hospital of Leiden was connected with the University and would have been the source of the cells, the original cells could also have come from a spontaneous abortion, i.e. a miscarriage.
Very confusingly, the term ‘abortion’ could even be used on its own whether it referred to a spontaneous, therapeutic or induced abortion. So if a scientist or doctor simply referred to ‘abortion,’ it was not clear what type of abortion it referred to. 
The use of professional terminology in this way is completely unexpected to our modern ears, especially that miscarriage or therapeutic abortion to save a woman’s life could be referred to by the term ‘abortion’ on its own.
So, please bear in mind when reading about cell lines and vaccines, that in general it is usually mistakenly assumed that the HEK293 cell line must have been derived from an elective abortion.
Even some widely-used, good fact-checker websites have unintentionally used the wrong information on the source of the foetal cells for the HEK293 cell line. As one such website states: “we know the abortion was performed at a hospital in Leiden, that the mother was healthy and elected to have the abortion, and that the father was unknown.”
However, the above information comes from the Minutes of an interview with the U.S. FDA Vaccines and Related Biological Products Advisory Committee on 16 May, 2001 (page 99), and in fact relates to the source of the PER.C6 cell line, and could not refer to the HEK293 cell line, which the Minutes also make clear. Unfortunately, as the original fact checker website is particularly trusted, the information has been picked up by other fact checker websites and so has spread further.
The PER.C6 cell line was also created in the Netherlands, but was obtained from an abortion in 1985, a year after the Termination of Pregnancy Act 1984 liberalised abortion. The cell line itself was created ten years later.
This cell line is definitely derived from an elective abortion, and is used in at least two other vaccines being developed. However, at the time of writing (24/2/2021),* no COVID-19 vaccines approved by the UK Government use this cell line.
* Update (27.2.2021) on the Johnson & Johnson vaccine (using the PER.C6 cell line):
The section on “Are any of the vaccines unethical,” has been written to provide you with information; not to tell you what decision to make. (Too many are already telling everyone what to do – usually not to be vaccinated!) But rather, to help you take ethical questions in vaccine development, particularly those using cell lines, to the Lord in prayer, and to make an informed decision.
Remember that there is no such thing as ‘the vaccine.’ There are many different types of vaccine, and this includes different ethical issues attached to different vaccines.
With the vaccines currently approved (Pfizer-BioNTech, Moderna and Oxford-AstraZeneca): some may feel reassured knowing that there is no foetal tissue in the currently-approved vaccines; others may feel that any historical link, however indirect and remote, is too much, even although elective abortion would not have been involved. Yet others may feel somewhere in-between, reassured about some vaccines, and not so sure about others; or still in the process of praying it through.
However, there is an important update on one of the vaccines not yet approved by the UK authorities:
The UK has pre-ordered one of the vaccines that uses PER.C6 cells (from Janssen Pharmaceuticals, a subsidiary of Johnson & Johnson).
Things move fast, and shortly after the original email on ‘Faith and vaccinations’ was sent out on 24 February, the 10pm news reported that the U.S. FDA staff had recommended that the Johnson & Johnson vaccine be approved by the FDA Vaccine and Related Biological Products Advisory Committee. That Committee met on 26 February and approved the vaccine for use in the U.S.A.
The Regulatory Authority in the UK, the MHRA, had commented earlier in February that they would need the final data from Janssen Pharmaceuticals before they could approve the vaccine. However, since the U.S. has now approved it, it may not be long before the UK does also.
It is a DNA viral vector vaccine, and the way it works is therefore very similar to the Oxford-AstraZeneca vaccine.
However, instead of a cell line which originated from either a single therapeutic abortion to save the woman’s life, or from a single spontaneous abortion (a miscarriage), it uses the PER.C6 cell line, which as described above, originated from an elective abortion.  This clearly raises additional ethical issues.
The Janssen vaccine is cultured in the PER.C6 cells, and then highly purified to remove the cells. Although the vaccine will not contain any of the original foetal cells from 1985, there is nevertheless, a historical link back to the original elective abortion, which will be a serious ethical concern for many. And some would definitely choose not to have this vaccine.
The Janssen vaccine has not yet been approved in the UK, so is currently not one that you would be offered. However, if you have not already been vaccinated, it would be best to settle in your heart how you would respond if that is the vaccine you are eventually offered.
When praying about being vaccinated yourself, it is helpful to remember what St Paul said in his letter to the Colossians: “Let the peace of Christ rule in your heart.” (Colossians 3:15)
In the Greek, it is even more specific: “Let the peace of Christ act as an umpire in your heart.” An umpire gives the decision: Is it in? or is it out?
For a Christian, with any decision it is important to be in a place of peace in our hearts with God. Often we may have to pray through something before we come to that place, and that can take some time. However, if you have come this far, you are probably more than willing to do that.
Although we have been told in the UK that we cannot ‘pick and choose’ which vaccine to have, that was really on the basis of how effective we perceived the different vaccines to be.
However, if you have a conscientious objection to any of them, then pray. And if offered one you are concerned about ethically, consider asking (preferably in advance, as only one type of vaccine may be available on the day) if you could have one that you would be happy with ethically. You may be surprised at the favour you receive.
There is also a need for new ethically-derived cell lines to be created. Please pray for those working towards this.
Whatever your decision about the vaccines, it is between you and the Lord. It is important not to judge others for their decision, and to remain in an attitude of love and unity with your fellow brothers and sisters in the Lord.
 Sahin, U. et al (2020) “BNT162b2 induces SARS-CoV-2-neutralising antibodies and T cells in humans.” medRxiv [Preprint]
Jackson, L.A. (2020) NEJM 383:1920-1931. “An mRNA Vaccine against SARS-CoV-2— Preliminary Report.”
 Xie, X et al (2021) Nat. Med. Feb 8th (Online ahead of print) “Neutralization of SARS-CoV-2 spike 69/70 deletion, E484K, and N501Y variants by BNT162b2 vaccine-elicited sera”
 Sahin, U. et al (2020) “BNT162b2 induces SARS-CoV-2-neutralising antibodies and T cells in humans.” medRxiv [Preprint]
 1967: Treffers, P.E. Population Studies 20(3):295-309. “Abortion in Amsterdam.” (Dept. Obstetrics and Gynaecology, University of Amsterdam, the Netherlands: uses the terminology ‘spontaneous abortion’ for miscarriage in the article.)
1984: Christiaens, G.C.M.L. and Stoutenbeek, Ph. Lancet 324:571-572. “Spontaneous Abortion in Proven Intact Pregnancies” (Dept. Obstetrics and Gynaecology at the University Hospital Utrecht, the Netherlands. Comment that: “In the Netherlands, spontaneous abortion is defined as the spontaneous expulsion of a fetus before 16 weeks of gestation.”) They use both the term ‘abortion’ and ‘spontaneous abortion’ for miscarriage in the article.
1985: Beard, R.W. et al, 1985, Lancet 326:1122-1123. “Miscarriage or Abortion?” Professor of Obstetrics and Gynaecology, St. Mary’s Hospital Medical School, London. Appealed to colleagues in a letter to the Lancet, to change their terminology concerning miscarriage; not to refer to it as ‘abortion.’ “Doctors use the word ‘abortion’ regardless of whether it was a spontaneous or induced event, yet our patients always speak of ‘miscarriages’ unless they have had a termination of pregnancy. It seems likely that the words have been interchangeable for many centuries…We would ask doctors, indeed all health professionals, to start using the word miscarriage rather than abortion for a spontaneous pregnancy loss before 28 weeks of pregnancy…
We hope that your readers will agree that a change from ‘abortion’ to ‘miscarriage’ is not just a semantic quibble but is well justified on humanitarian grounds.”
2013: Moscrop, A. J. Medical Humanities 39:98-104. “’Miscarriage or abortion?’ Understanding the medical language of pregnancy loss in Britain; a historical perspective.” Points out the ambiguity of abortion terminology in scientific articles: “However, it remained ambiguously designated: ‘abortion’ was often used in the medical literature without a clarifying prefix (‘spontaneous’ or ‘induced’) to describe spontaneous pregnancy loss, induced termination of pregnancy or (deliberately exploiting the dual meaning of the term) both.”
2021: Midwifery website, the Netherlands, February 2021: https://www.vkutrechtoost.nl/en/pregnant/miscarriage
Although using the term ‘miscarriage’ on the website, which was for patients, they explained that: “The medical term for a miscarriage is ‘spontaneous abortion.’
 The decision to use the cell line will have been for scientific reasons, not because of the origin of the cells.