Vaccines have played an important role in reducing the impact of devastating diseases on the health of people worldwide.  However, some vaccines are produced using cell lines derived from aborted fetuses.  In this review, we will consider:

  • why the use of these vaccines is morally problematic
  • the bioethical principles of cooperation with evil, scandal, and informed consent
  • the moral responsibilities one has in using one of these vaccines
  • practical considerations when evaluating the benefits and risks of such vaccines.

 The problem with some vaccines

Certain vaccines are produced in the laboratory using technology that relies on “mammalian cell lines” rather than the traditional chicken egg process used to replicate the virus intended for the vaccine.  This cell culture technology has the advantage that cell lines used to produce a vaccine can be “banked” in advance of the need, so that in a pandemic outbreak for example, the process of manufacturing a large supply of vaccine might be accelerated. Improved effectiveness of vaccines produced with this methodology is also reported. 1 

These cell lines may be derived from non-human sources (e.g. canine tissue), but some cell lines have been produced using “biological material” originally derived from human tissue sources obtained through the act of a procured (elective) abortion in the past.  It is important to make this distinction regarding the source of the cell line, because the use of cell lines derived from aborted human fetal sources is morally problematic.  This is true even though, over time, these cell lines have grown independently such that the current cells are very far removed from the original fetus from whom the first cells were taken.  They still carry the same genetic code present in the DNA when this unique human being was first conceived.  Since morally derived cell lines exist and have been used successfully, there is no legitimate reason to use cell lines originating from aborted human fetuses. 2 

It is also important to know that with cell culture technology the vaccine viruses  are produced in the “descendant cells” of the cell line not from them, that is, employing the cells as a “growth factory” of sorts. 3  Furthermore, the descendant cells are not a fetus, are not part of the original aborted fetus (the cells are separated by many generations), and are removed from the final vaccine product through a purification process.  However, some residual DNA, unique to the aborted fetus from which the cell-line was created, can be present in the vaccines produced by this process according to manufacturers’ package inserts. 4  Finally, it is not the cell lines themselves that pose the moral issue, so much as it is the process by which they were produced originally, that is, how they came to be available through the gravely immoral act of abortion.

It is also noteworthy that some pharmaceuticals, that is, medications people take for the management of some diseases, are also produced through methods employing biological materials derived from aborted human life and so, the same principles apply.

 The bioethical issues of these vaccines

Direct abortion is a gravely evil act because it is the deliberate killing of an innocent human being who is unique and unrepeatable, with immeasurable value. 5  In addition, the corpses of all human embryos and fetuses, directly aborted or not, must be treated with the same dignity and respect as all other human remains.6  And finally, the sacrifice of human life for therapeutic purposes is wholly immoral and incompatible with human dignity because it is the exploitation of one human being in the involuntary service of another.7 Therefore, abortion is a morally evil act which cannot be voided or reduced in gravity by the misguided intention to help cure the sick with the resulting human remains.  Neither abortion nor any of its by-products, however well intentioned, can be justified, approved or promoted. 8 

Any procured abortion, as well as the direct use of the resultant corpses to produce cell lines for medical research or therapy, constitute gravely evil acts, but these acts are not performed and are not necessarily condoned by those who might benefit from them remotely (both spatially and temporally). This is the case with vaccine production which relies on cell lines that were derived from human fetuses aborted many years ago, but that are used by researchers today to produce vaccines administered to patients now.  Distance from the sentinel sin, though, does not eliminate fully any connection to that sin.

Some secular ethics committees conclude that the use of illicitly obtained biological materials is permissible when there is a separation between those who prepare and distribute the materials and those who use them for experimentation and therapeutics.  While this separation is necessary, it is not sufficient to assure moral justification to use these materials.  Indeed, it is contradictory for someone to condemn the injustice of abortion, but to pursue for his professional work or personal gain, the resulting “biological material” (or products made from this, such as cell lines) obtained from that injustice.  Such use constitutes material cooperation with evil, and may also result in scandal. 9

Formal cooperation with evil occurs when one directly helps and shares the intention of the individual perpetrating the evil act.  It is always morally wrong. 10  Material cooperation with evil occurs when one does not directly perform or intend the evil act committed by another, but his actions to some degree fulfill or allow the conditions necessary for the immoral act to occur. 11 Because of differing degrees regarding one’s responsibility and how essential one’s role is to the evil act, material cooperation may or may not be morally permissible.  Immediate material cooperation is assistance that is essential to commission of the evil act and is not morally licit.  Mediate material cooperation includes actions that are not essential to commission of the evil act; they may be morally licit when they are sufficiently removed from the evil.  Every situation must be considered in its own context, but in general, any steps in the production and promotion of vaccines using immoral biological material is indispensable, i.e. “too essential,” to be morally permissible because those activities continue demand for these cell lines and may encourage contemporary abortions for new cell lines.  However, consenting to immunization with one of these vaccines, in general, is considered “very remote mediate material cooperation” and can be morally licit when there is sufficient reason and no other choice than to accept the objectionable vaccine or refuse any vaccination at all. 12 

Scandal is an attitude or behavior that leads another to commit sin. 13   It is always a concern when there is the possibility that others may perceive a connection with sin even when one does not exist.  The more prominent, influential or authoritative one’s role is, the more significant is his responsibility to avoid scandal.  Therefore scientists, politicians, and doctors have a greater degree in controlling the vaccines available to the public than individuals seeking merely to take proper care to protect and maintain good health.

An important tenet of healthcare both morally and legally is informed consent.  This is the process by which a patient is provided with the necessary information regarding risks, benefits, alternatives, possible ramifications of declining the treatment, etc. for a treatment so that he can determine whether a treatment is directed towards his desired ends.  It is intended to respect a patient’s autonomy, i.e. his ability to make decisions for himself as a reflection of his own values.  This process is recorded in a document of the same name. 14  Information regarding a vaccine’s development is a fact of vital importance because of the associated moral implications; therefore, it should be part of the informed consent process.  There are no federal requirements for informed consent related to vaccinations, but policies are regulated on the state level. 15 A patient should feel free to request this information if it is not automatically disclosed.

Ultimately, the assessment of a situation and one’s response is not so burdensome if we keep in mind that, “Behind every “no” in the difficult task of discerning between good and evil, there shines a great “yes” to the recognition of the dignity and inalienable value of every single and unique human being called into existence.”16 

 Your moral responsibility

Along with the fundamental right to life, one has a moral duty to preserve his life and maintain health using reasonable means. 17  At the same time, he also has the moral duty to avoid sin, that is, to save his soul which is the supreme purpose of his existence and accomplished through the good works he performs in this earthly life. 18 

In general, vaccines are considered a safe and effective means to safeguard one’s health by reasonable measures, but they raise a moral dilemma when their production in some way involves the use of cells from aborted human life.

For example, in all circumstances, a research professional must refuse to use illicitly obtained biological material because he has a duty to remove himself “from a gravely unjust legal situation and to affirm with clarity the value of human life” through the active witness of his work. There is no moral justification for the use of these objectionable cell lines in producing vaccines. 19 Likewise, it is not morally permissible for a sales representative to promote the use of vaccines or other pharmaceuticals derived from these morally compromised methods.  These professionals can (and must) choose morally produced alternatives to accomplish their work goals.  Continuing to use these cell lines or promoting the products made with them implicitly condones the unacceptable origin of the cell lines, leads to a cultural desensitization in the practice of using aborted fetal cell lines, and perpetuates demand for them.

On the other hand, it can be morally licit for someone, especially parents, to consent to immunization with a vaccine produced using cell lines derived from aborted human life.  Their roles are much more distant from and less influential on the primary evil act of abortion than those more directly involved in the production, distribution and marketing of the cell lines and vaccine products.  Other than refusing the vaccine which can provide protection against a serious disease, parents and patients may have no choice in the matter if there are no morally produced alternatives.  Therefore, immunization with a vaccine, even if it was produced using cell lines derived from aborted human fetuses, can be morally licit because any cooperation in evil by the parent or patient is very remote and essentially outside of his direct control.  However, after properly educating themselves on these vaccines and assessing the health dangers of avoiding vaccination, several conditions must be met:

    1. the vaccine protects against a serious illness
    2. there are no moral alternatives of equal safety and efficacy that are reasonably available and
    3. they fulfill their duty to protest the use of morally objectionable cell lines in the vaccine’s production and demand that morally produced vaccines be made available; this can be registered with the manufacturer, local healthcare systems and legislative representatives.

The decision to immunize with one of these vaccines is generally considered to be a matter of prudential judgment meaning that two people of good faith and properly formed consciences can arrive at opposite conclusions and yet both can hold morally acceptable positions for their unique situations. If one elects to decline vaccination based on a thorough evaluation of scientifically sound information, this can be morally legitimate; indeed it can be a noble and courageous exercise in conscientious objection.  But, especially for highly contagious diseases with serious symptoms, one must weigh the potential compromise to his and others’ health. The Pontifical Academy for Life has stated that it can be morally permissible to accept a vaccine developed using aborted fetal cell lines if there is sufficient reason; indeed, one may refuse the vaccine only “if it can be done without causing children, and indirectly the population as a whole, to undergo significant risks to their health.” 20  Also, it must be emphasized that the Catholic Faith  views vaccines in general as a valuable good to protecting life; it does not categorically forbid the use of vaccines, even when derived from these objectionable cell lines.  And so, a faithful Catholic cannot claim a religious exemption when refusing a particular vaccination; this would more properly constitute a conscience exemption. 21 

Lastly, since the widespread, unopposed use of immorally derived biological materials cultivates a general acceptance of these products, attention must be paid to the duty of all faithful citizens to  respectfully but heartily pressure manufacturers, health care systems and politicians to make available vaccines and pharmaceuticals without these moral difficulties. By failing to exercise conscientious objection or voice criticism against these moral evils, when one has the duty to do so, itself represents a passive material cooperation in evil. 22 

 Regarding the COVID-19 vaccines in development

Several vaccines to protect against the SARS-CoV-2 virus that causes COVID-19 (the disease) are in the process of development.  Some of these are using the morally objectionable cell lines derived from aborted fetal tissue, although a good number of vaccines in development are not. 23 All faithful citizens should express the concerns outlined above to their political representatives, regional health care systems, the vaccine manufacturers and their own medical providers. To begin, you can take action here:

Given the gravity of the disease burden caused by this novel coronavirus, once vaccines are publicly available, immunization in the interest of preserving personal and public health could be deemed a reasonable justification to use a vaccine that was produced with immorally derived cell lines—as long as there are no reasonably available, morally-derived alternatives at that time.

When safe and effective vaccines are available, it is imperative that informed consent for administration of the vaccine includes this vital information regarding the manufacturing process so that one can make a valid and moral choice in consenting to vaccination.  At the very least, one should be provided with manufacturer’s information, so he can research the vaccine’s development with some readily available resources (see below).  One has a duty to convey these concerns to his or her medical provider and insist that morally produced vaccine alternatives be made accessible in the office.  It is also a good time to bring attention to the fact that many other vaccines against viruses and an increasing number of pharmaceutical agents use these immorally derived cell lines.  In this way, we can “respect, protect, love and serve life, every human life!” 24

 Vaccine Considerations

These are reasonable and legitimate questions to ask about the disease, your situation, and the vaccine itself when making a prudential judgment about any particular vaccine. For every disease, personal situation, and vaccine there will be different answers for different people and those answers could change with circumstances over time. The list is not exhaustive, but meant to help you think about the complexities of any vaccine decision and some of the considerations necessary for the proper formation of conscience in this matter.

• How serious is the disease prevented (e.g. minor symptoms, hospitalization, death, etc.)?
• How contagious is the disease prevented (e.g. not easy to spread, very contagious, etc.)?
• How is the disease transmitted (e.g. casual contact, airborne, blood borne, intimate contact, etc.)?
• What is your exposure risk (this is dependent on living arrangements, work, what types of activities you do that relate to the mode of transmission, i.e. do you perform the type of activity or find yourself in an environment in which the pathogen is commonly spread)?
• If the disease is contracted, are there treatment options available?
• If there are treatments, how difficult is it to access them (e.g. is it home-based, does it involve over-the-counter vs. prescription medications, does the treatment involve significant side effects, is hospitalization necessary often, etc.)?
• What is your typical access to health care (e.g. could you get the appropriate level of care if you contracted the disease and needed treatment)?
• If you do not get immunized, do you pose a significant threat to others (e.g. do you live with someone who has impaired immunity)?
• Do you have natural immunity (e.g. have you had the disease and recovered)?
• How effective is the vaccine (i.e. does it reduce disease severity or prevent all disease, are there populations in which it is not effective?)
• Does the vaccine itself have significant risks to health or side effects?
• Was the vaccine tested thoroughly for safety or fast-tracked for urgency?
• Was the vaccine produced using moral methods and materials (e.g. were cell lines from aborted human fetuses used, were humanized animal models (hybrids or chimeric species) employed in testing—neither of which are morally licit)?

 Other Resources

Bioethics on Air: NCBC Podcast: Episode 33: COVID-19 and Ethical Challenges to Vaccine Development

Children of God for Life (vaccine chart and COVID-19 vaccine development)

USCCB letter to the FDA opposing development of vaccines using fetal cell line


Sankarasubramanian Rajaram, et al., “Influenza vaccines: the potential benefits of cell-culture isolation and manufacturing,” Therapeutic Advances in Vaccines and Immunotherapy 8 (2020): 8. doi:10.1177/2515135520908121.

Rajaram, “Influenza vaccines,” 5.

Children’s Hospital of Philadelphia. “News & Views: Why Were Fetal Cells Used to Make Certain Vaccines?” (accessed May 7, 2020);

Rajaram, “Influenza vaccines,” 5;

Centers for Disease Control and Prevention. 2020. Vaccine Excipient Summary.;

Children’s Hospital of Philadelphia.  “Are Fetal Cells Used to Make Vaccines?” (accessed May 7, 2020).

 John Paul II, Encyclical on The Gospel of Life Evangelium vitae (March 25, 1995) §62.

Congregation for the Doctrine of the Faith, Instruction on Respect for Human Life Donum vitae (February 22, 1987) Part I, §4.

Alexander Pruss.  “Cooperation with Past Evil and Use of Cell-Lines Derived from Aborted Fetuses,”  Linacre Quarterly.71(3) (2004): 338.

Congregation for the Doctrine of the Faith, Instruction on Certain Bioethical Questions Dignitas personae (September 8, 2008) §30.;

John Paul II, Evangelium vitae, §63.

Spontaneous abortions (miscarriages) with informed consent by the parents may be morally legitimate sources for these cell lines but are not ideal because 1) miscarriages are unpredictable, so collection is difficult and may be emotionally difficult and 2) the cells themselves may exhibit biological disadvantages that led to the miscarriage.

Direct abortions can never be acceptable sources for cell lines because legitimate consent by parents cannot be obtained.  Society removes parental rights from parents who harm their children, so in consenting to the intended death of their child through abortion, parents naturally abrogate the authority to make further decisions regarding the child’s good, even their remains.

John Paul II, Evangelium vitae, §63.

Congregation for the Doctrine of Faith, Dignitas personae, §35;

Pontifical Academy for Life, “Moral Reflections on Vaccines Prepared from Cells Derived from Aborted Human Fetuses,” The National Catholic Bioethics Quarterly 6, no. 3 (2006): 545-547, doi:10.5840/ncbq20066334.

10 Austin Fagothey, Right and Reason: Ethics Based on the Teachings of Aristotle & St. Thomas Aquinas (Rockford, Illinois: TAN Books, 1959), 338.

11  Fagothey, Right and Reason, 338-339;

Pontifical Academy for Life, Moral Reflections, 545.

12  Pontifical Academy for Life, Moral Reflections, 547-548.

13Catechism of the Catholic Church with modifications from the Editio Typica, 2nd edition Washington, D.C.: USCCB Publishing, 1997, 2284.

14  Daniel E. Hall, Allan V. Prochazka and Aaron S. Fink, “Informed consent for clinical treatment,” Canadian Medical Association Journal 184, no. 5 (2012): 533-534, doi:10.1503/cmaj.112120.

15  Centers for Disease Control and Prevention. “Vaccination Requirements and Laws,” (accessed May 7, 2020);

New York State Department of Health. “Immunization Laws and Regulations,” (accessed May 7, 2020).

16  Congregation for the Doctrine of Faith, Dignitas personae, §37.

17  Fagothey, Right and Reason, 300.

18  Fagothey, Right and Reason, 275.

19 Congregation for the Doctrine of Faith, Dignitas personae, §35.

20  Pontifical Academy for Life, Moral Reflections, 548.

21 United States Conference of Catholic Bishops. 2015. Conscience Exemption for Vaccines based on Fetal Tissue from Abortions.

22 Pontifical Academy for Life, Moral Reflections, 547-548.

23  Children of God for Life, “Leading Coronavirus Vaccine Development Using Cells of Aborted Babies.” (accessed April 28, 2020).

24  John Paul II, Evangelium vitae, §5.