The ethical derivation of vaccines for COVID-19

A woman models a small bottle labelled "Vaccine COVID-19" in this illustration photo April 10, 2020. (CNS photo/Dado Ruvic, Reuters) See BISHOPS-ETHICAL-COVID-VACCINE April 20, 2020.


It is generally accepted that a Covid-19 vaccine provides the best possibility of an “exit strategy” from the pandemic that is currently sweeping the world. Many companies around the world are currently working to produce such a vaccine – reports detail that there are more than 100 different vaccine projects underway, with eight already being studied in humans.

Human vaccines are typically developed using human cell lines – cell cultures developed from a single human cell. One of the sources of the cells used for human cell lines is tissue from aborted fetuses, something which presents a significant moral dilemma for Catholics and others. Catholic teaching upholds the principle of the inviolability of human life which precludes the use of human embryos or aborted fetuses for medical research. Put another way, we should never use another human life as a means to an end, no matter how good the intention.

There are some companies using only ethical cell lines for the development of a coronavirus vaccine. Recently, in the United States, a group of mostly Catholic advocates, including some bishops, have appealed to federal health authorities to ensure that research on coronavirus vaccines occurs using cell lines free from any connection to abortion. If such a vaccine is successfully produced, there are no moral issues, related to abortion, associated with its use.

However, there are other companies using cell lines that have been derived from aborted fetuses. This means that there is a real possibility that a successful vaccine, and there may only be one, could be directly linked to human abortion, whether recent or in the distant past.

This is not a new dilemma. The rubella vaccine, for example, derives from the WI-38 cell line that uses lung tissue from a 3 month-gestation female fetus aborted in the 1960s. The specific dilemma for those who oppose abortions of any kind is the extent to which, in using such a vaccine, we are condoning abortion and potentially encouraging further abortions. Put another way, the question is whether there is a contradiction between opposing abortion and consenting to a vaccination programme.

The Pontifical Academy for Life has previously spoken out on this, stating in a 2005 document that, when the cell lines being used are “very distant” from the original abortions, then there is no “morally relevant” cooperation between those who use the vaccine and the original abortion. Assuming there are no other effective ethical alternatives (which should always be preferred), the academy concludes that it is not just morally acceptable to use such a vaccine but, where the vaccination coverage is necessary for the safety of others, there is a “moral obligation” to use it.

Critical to the Pontifical Academy’s conclusion is the fact that the ongoing production of the vaccine does not rely on or require new abortions. This rationale would apply equally to a coronavirus vaccine that was produced from a historical cell line linked to an abortion. In the event there was no other alternative for immunising people against the coronavirus, it would be not just morally acceptable, but arguably obligatory.

These days, there are ethical cell lines and processes available to produce the cell lines necessary to produce vaccines that do not rely on abortions. However, there are still some companies using cell lines derived from recently aborted cells (as opposed to historic cell lines). In the event there were no other ethical effective alternatives, we could realistically find ourselves having to choose between using a morally unacceptable vaccine produced from such a cell line or not being immunised.

This would pose a genuine dilemma for many. How would this be resolved? The use of such a vaccine would ultimately be a matter of individual conscience.

On the one hand, by deciding not to take such a vaccine, an individual would be making a strong and prophetic stand in favour of the value of human life. At the same time, they would be rightly rejecting any sort of utilitarian calculus by which it might be reckoned that the death of a “few” innocent human lives is outweighed by the potentially millions of lives that would be saved. The Catholic moral tradition rejects any approach to decision-making that is based entirely on a numerical calculation – the morality of any action cannot be decided on consequences alone. This is another way of saying that the morality of our intentions is not always sufficient to make an action moral – in the Catholic moral tradition we have to weigh up the morality of the “means” as well as the morality of the outcome or intention.

On the other hand, in the messiness of life we do sometimes have to choose between two “bad” outcomes. In weighing up whether we might refuse a coronavirus vaccination, it becomes evident that the impact of such a decision creates a risk not just for ourselves, but also for many others. That is because the impact of not being vaccinated means we risk passing on a potentially fatal virus to the people we live, work and socialise with, in particular vulnerable people with underlying conditions. We may not want that to happen, but it remains a foreseeable and highly likely consequence of not being vaccinated. It would be different if the burden of taking such a decision only fell on the decision-maker; however, in rejecting the only viable vaccine, we would also be taking that risk on behalf of (potentially many) others without their consent. That is equally something we are not ethically entitled to do.

That is why some Catholic ethicists have concluded that there is “no absolute duty” to boycott any Covid-19 vaccine produced with the help of cells recently derived from aborted fetuses, when no other alternatives exist. I personally agree with that conclusion, while hoping that such a scenario never presents itself.

That means I also support advocating for researchers to carry out any new research only on cell lines that are morally acceptable.

  • Dr John Kleinsman is director of the NZ Catholic Bioethics Centre.
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Reader Interactions



    Dear Dr. Kleinsman,
    I am the developer of the WI-38 normal human fetal cell strain cited in your article.
    I would like to send to you an article that might interest you. Please send me you email address.
    Mine is

    Thank you.

    Leonard Hayflick
    Professor of Anatomy
    University of California, San Francisco

  2. Eileen Mosquea says

    Dear Dr. Kliensman,

    I am a catholic mother of seven , i don’t agree with abortion. I am a registered nurse and my late husband a surgeon and practising catholic. I realise that you are not a MD . My opinion is that the intent behind finding a vaccine to this horrific pandemic is good. God gives the intelligence to the scientists and of course moral thought he is the one to judge. We can only do our best with the situation in hand.

    Thank you

  3. Mari says

    Thank you for your article. The answer I have not heard yet is if the vaccines for New Zealand are ethically sourced. Second, has there been any work done to petition the government to provide NZ with an ethically sourced vaccine?


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