As quarantines are lifted across the US and the world, many continue to ask whether there are more permanent measures that can be taken against COVID-19. The most important of these will be a vaccine. Dozens of COVID-19 vaccines are being developed worldwide. These efforts involve different molecular strategies and manufacturing processes. For example, a British research group at the University of Oxford has engineered a chimpanzee cold virus that contains important fragments of the SARS-CoV-2 virus that causes COVID-19. This chimpanzee cold virus is being grown in human fetal cells. When injected into macaques, this engineered virus acted as a vaccine, triggering an immune response that protects these primates so that they did not develop serious disease.

In contrast, a Chinese research group at Sinovac, Inc., has grown SARS-CoV-2 in African green monkey cells, then killed the virus. When injected into macaques, this inactivated virus acted as a vaccine, too, triggering an immune response that protected the primates from future SARS-CoV-2 exposure. Both of these promising COVID-19 vaccine candidates have entered into human clinical trials.

Though it is not clear whether both or either or neither of these vaccines will eventually be approved for widespread human use, their distinct manufacturing processes raise an important ethical question. Why? Because the British COVID-19 vaccine was developed using human fetal cells commonly believed to have been obtained from an elective abortion. Many Americans are rightly concerned about the morality of using vaccines developed from aborted fetuses. If it is eventually approved, should a citizen of conscience who is opposed to abortion avail herself of the British vaccine to protect herself and her loved ones during this time of pandemic?

The Science of Human Fetal Cell Lines

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Why do some claim that we need aborted fetal tissue for vaccines in the first place? The answer is complex. Growing human cells in a laboratory environment is not easy, and the earliest attempts to do so in the middle of the previous century often ended in failure. To make their task easier, cell biologists sought to obtain the freshest and youngest human cells they could find, which in many cases were cells obtained from human fetal remains. Three of the most successful human cell lines developed then—WI-38, MRC5, and HEK293—are human fetal cell lines. WI-38 cells were derived from cells obtained from a 12-week old fetal lung taken from an aborted fetus in the early 1960s; MRC5 cells were derived from cells taken from the 14-week old fetal lung of an aborted fetus in 1966; and HEK293 cells were isolated from cells taken from a fetal kidney of unknown gestational age in 1973.

Though HEK293 is commonly believed to have been obtained from an aborted human fetus, I received an e-mail a few months ago from Professor Frank Graham, who established this cell line. He tells me that to the best of his knowledge, the exact origin of the HEK293 fetal cells is unclear. They could have come from either a spontaneous miscarriage or an elective abortion. Regardless, the abortions that gave rise to the three cell lines—or in the possible case of HEK293, the miscarriage—happened decades ago. The aborted fetuses are long gone, as are the original fetal cells. There are no fetal body parts or fetal tissue left. Only distinct, new cells derived from the original fetal cells remain.

Today these fetal-derived cells are used extensively in biomedical research—at this time, 58,094 scientific papers have already been published that are associated with HEK293 alone—and they were instrumental in the development of numerous drugs and medical treatments. For example, HEK293 cells were used to study the human dopamine receptor, and many of the antipsychotic drugs used to treat mental illnesses like schizophrenia and bipolar disorder would not have been discovered without them. More recently, cutting-edge CAR-T immunotherapies that are being used to save the lives of advanced-stage cancer patients also rely on HEK293.

The British vaccine group at the University of Oxford used HEK293 to grow their chimpanzee cold viruses that contain a fragment of SARS-CoV-2. Why did they use these and not other cells? Probably because HEK293 cells are very efficient viral factories that give rise to large numbers of viruses at any one time. I have spoken to scientists who have tried to identify other human cell lines for the production of specific viral tools, and no robust alternative has been found. For culturing many of the viruses that are commonly used in biotechnology, HEK293 are simply the best cells we have today to do this, by far.

Moreover, HEK293 is an established cell line. What this means is that these cells have been used and studied by biologists for nearly half a century. They are well characterized, and they have been validated for their safety. I point this out because it helps explain why it is unheard of for a vaccine manufacturer to seek out new human fetal cells from a recent abortion. Such novel fetal cells would be uncharacterized, unvalidated, and unapproved by regulatory agencies like the U.S. Food and Drug Administration (FDA) for human vaccine production. Why waste time, effort, and money to obtain, characterize, and validate new human fetal cells when the classic fetal cell lines obtained decades ago like HEK293 are readily and cheaply available? Regrettably, Chinese scientists have recently established a novel human fetal cell line from an elective abortion for biomedical research. This was unnecessary, especially in light of the proven success of HEK293.

The Ethics of Appropriation of Evil

We live in a world where persons of virtue live with and are surrounded by persons of vice. Often, we benefit from present and past actions of individuals and institutions that are entangled with evil. How are we to live in such a morally complicated world? The ethical strategy to evaluate scenarios where one finds oneself entangled with possibly benefiting from a past evil act involves considering whether or not this appropriation of evil is morally justifiable. An appropriator is someone who benefits in any way from a past action of an agent, in this case, from a past evil act.

If the appropriator approves of the evil act, then he is culpable of evil: He is formally appropriating the evil of the past action. The man who purchases a stolen item, grateful that the theft happened and that he is benefiting from it, did not himself commit burglary. However, he is still culpable of evil because he consented to an unjust act. He therefore is an unjust man. If the appropriator does not approve of the evil act, then he may or may not be culpable of evil, but he is still materially appropriating the evil of the past action. If his appropriation of the past action contributes to future evil acts, then he is culpable of evil as well.

This could happen in two ways. First, the appropriator could make the person who committed the past evil action think that his evil act was in fact, not evil. This is the moral offense we call scandal. The man who purchases the stolen item may, because of his actions, convince the burglar that theft is not evil. The burglar steals again. Second, the appropriator could make the person who committed the past action think that he should commit it again because he would benefit again from the appropriator’s future actions. This is the moral offense we call cooperation. Here, the man who purchases the stolen item may, because of his actions, cause the burglar to believe that if he stole again, the appropriator would reward him with another purchase. In this case as well, the burglar steals again.

If either of these scenarios is realized, then the appropriation of the past evil action would not be ethically justified. In contrast, if the appropriation of the past evil action does not contribute to future evil acts, it could be justified for a grave proportionate reason. Why for only a grave proportionate reason? Because a virtuous person would do whatever is reasonable to avoid any avoidable association with evil whatsoever.

What Does All of This Mean for COVID-19 Vaccines?

Now let’s turn to the ethical question of using COVID-19 vaccines—or anti-psychotic drugs or cancer immunotherapies—developed with human fetal cell lines obtained from an elective abortion. In light of the ethical framework described above, I propose that using these medical therapies would be morally justifiable only if their use did not contribute to future evil acts and if their use was occasioned by a grave proportionate reason.

Recall that the appropriation of an evil act would not be justifiable if it contributed to future evil acts because of scandal or cooperation. Therefore, a citizen of conscience who is opposed to abortion could avail herself of the British vaccine or any vaccine developed using fetal cells from an elective abortion only if she avoided scandal by making her opposition to abortion absolutely clear. For example, she should make it known that if several COVID-19 vaccines are developed with different production strategies, then she would explicitly reject the vaccines manufactured with fetal-derived cells and opt for the non-fetal alternatives, even if this is an inconvenience. Actions like these make her moral convictions unambiguous in the public square.

Next, since it is unreasonable to think that vaccine manufacturers would solicit future abortions to develop future vaccines, she could also rest assured that she is not cooperating with evil. She is not encouraging them to engage in future evil acts. However, I recommend that a citizen of conscience who is opposed to abortion should consider supporting efforts to urge vaccine manufacturers to discover non-controversial cell lines that are as good as HEK293 for viral production. This way, she would be nudging vaccine companies not to future evil acts but to future good ones.

Lastly, her act of appropriation is justified by the grave proportionate reason that she is protecting herself, her loved ones, and the community from the scourge of contagion and possible illness or death.

Finally, there may be some in society who would still object to using vaccines developed with human fetal cell lines even if it is ethically justifiable. May they refuse to be vaccinated? I think so. We acknowledge the right of the individual to refuse to engage in certain acts as a conscientious objector. However, society also has a right, and indeed, a moral obligation, to protect its citizens from illness and death. Therefore, justice demands that we balance these competing interests in our communities.

Our established social practices with yellow fever, a viral disease found in many tropical areas in the world, suggest one possible way to do this. To prevent the spread of the yellow fever virus, yellow fever vaccinations are required for travelers to enter numerous countries around the world. Those who are traveling from nations where yellow fever is common and yet who choose not to vaccinate themselves against yellow fever are free to do so, but they are also not permitted to enter those countries that require a yellow fever vaccine from travelers to protect their own citizens.

I could imagine a similar scenario with COVID-19. Persons of conscience should be free to refuse vaccination against COVID-19 even if they live in a society with community spread of that disease. However, their communities should also be free to protect the common good by not permitting them to enter schools, restaurants, malls, airports, and other public spaces where they may unwittingly catch or spread the disease.

In sum, we live in a morally complex world where we stand to benefit from the present and past actions of both virtuous and vicious agents. However, there are ethical principles that can help us to maneuver around and through these moral complexities without losing our moral integrity. In the current pandemic, the ethical principles that govern the appropriation of evil acts reveal that citizens of virtue can avail themselves of COVID-19 vaccines made with human fetal cell lines if they avoid scandal in the public square by first making their opposition to abortion absolutely clear.