Should Catholics Receive a COVID-19 Vaccine?


On January 30th, 2020, the World Health Organization declared a public health emergency of international concern in the wake of the rise of the novel coronavirus, COVID-19.1  Since then the virus has raged across the world, leading to the spread of over 60 million cases2 and over 1.5 million deaths across the world.3 The exponential growth and rapidly rising death toll attributed to this virus has sowed intense fear among many in the human family and has drastically changed daily life.

In response to this coronavirus, people are avoiding large crowds, social distancing, and wearing masks. Many daily activities that were previously taken for granted, like going to school or work, dining in a restaurant, or attending a sporting event, have been either suspended or seriously altered, resulting in catastrophic socio-economic damage.4 While most people yearn to return to life as it was before the outbreak of this virus, many experts believe this will only be possible once a vaccine becomes widely available.5

In response to the need for an effective vaccine, on May 15, 2020, the U.S. government announced Operation Warp Speed with the expressed goal of using the resources of the federal government and the private sector to “accelerate the testing, supply, development, and distribution of safe and effective vaccines, therapeutics, and diagnostics to counter COVID-19 by January 2021.”6 This public-private partnership has led to the development of numerous vaccines in phase 3 trials preparing to seek emergency use authorization from the FDA.

In the race to create a safe and effective COVID-19 vaccine, three well-known pharmaceutical companies, Moderna, Pfizer, and AustraZeneca, have taken the lead and are preparing to seek emergency use authorization from the FDA for their vaccines. After enrolling 30,000 participants in a phase 3 trial, the mRNA-1273 vaccine, codeveloped by Moderna and the National Institutes of Health, was shown to be 94.5% effective in preventing the COVID-19 virus.7  Similarly, the Pfizer mRNA vaccine, BNT162 showed itself to be 95% effective after its phase 3 trial with over 40,000 participants.8 AstraZeneca, using research from Oxford University, took a different approach to their COVID-19 vaccine, producing a weakened adenovirus vaccine which showed itself to be 90% effective after a phase 3 trial with over 23,000 participants.9

Are these vaccines ethically created?

In the wake of very hopeful scientific news regarding the efficacy of these three vaccines, some Catholics have sounded a moral alarm over how these vaccines were researched, tested, and produced. Specifically, there is concern that these vaccines may have been produced from cell lines derived from illicit origins, including cells derived from aborted fetuses.10

Both Pfizer and Moderna created an mRNA vaccine.11 Instead of injecting a weakened or inactivated germ into the human body, as many vaccines do, mRNA vaccines coach the body to create a protein which triggers an immune response inside the body to which the immune system produces antibodies which protects a person from becoming infected if the real virus enters the body.12  As mRNA vaccines, both the Pfizer and Moderna vaccines are designed and developed without the use of abortion derived cell lines. While the design of these vaccines gives assurance that no illicit material was used in the design or production of the vaccines, there is evidence to suggest that both of these vaccines were tested using the abortion-derived pseudovirus HEK-293 cell line.13

The AstraZeneca vaccine took a more proven approach and created an adenovirus vector vaccine.14 This vaccine uses a non-replicating chimpanzee adenovirus which delivers a SARS-CoV-2 (the virus that causes COVID-19) spike protein intended to induce an immune response. This protein, in turn, trains the human’s immune system to build antibodies to the COVID-19 virus. The production of the SARS-CoV-2 adenovirus does make use of HEK-293 cells.15

Tragically, all three vaccines have ties to the cell line HEK-293. This cell line was generated in 1973 in the Netherlands and originates from the embryonic kidney of an aborted fetus.16 Since an embryo “must be treated from conception as a person, the embryo must be defended in its integrity, cared for, and healed, as far as possible, like any other human being”17 it is never permissible to perform the evil of abortion, for research purposes. Since all three of these vaccines have ties to HEK-293, they bear some cooperation with the abortion that led to the creation of the cell line. Understanding cooperation with evil to be “any free and knowing assistance of an individual or institution in an immoral act performed by another individual or institution,”18 a person’s choice to receive one of these vaccines is de facto a choice to participate in a very remote way in the evil of that abortion.

Sadly, it is nearly impossible to avoid some form of remote cooperation with evil in the modern world. Yet there are different ways of cooperating with evil which are important to evaluate when considering the morality of such cooperation. For example, it is clearly worse to cooperate in an evil if someone wants the evil to occur than if someone is forced to cooperate in an evil that they do not want to occur and would avoid if they had another alternative.

While such cooperation is never ideal, Catholics can cooperate with evil so long as they do not will the evil to occur, their cooperation does not make a contribution that leads to the commission of the evil action, there is significant distance from the immoral action, and the person has a proportionate reason for the cooperation. In other words, so long as the person’s choice to make use of a vaccine derived from illicit origins does not lead to another abortion occurring, one can morally make a proportionate choice to receive that vaccine after considering the remoteness of the cooperation with the evil action, and the lack of other moral alternatives. When considering the facts, one must make a prudential judgement as to whether the good achieved by participating is greater than the gravity of the undesired, yet foreseen evil.

In 2008, the Congregation for the Doctrine of the Faith clearly taught that there could be proportionate reasons which may justify the use of vaccines derived from illicit matter. “For example, danger to the health of children could permit parents to use a vaccine which was developed using cell lines of illicit origin, while keeping in mind that everyone has the duty to make known their disagreement and to ask that their healthcare system make other types of vaccines available.”19 Thus, Catholics and people of goodwill could make a prudential judgement that in certain cases — for example, if they are immunocompromised or they work in a COVID-19 unit — there is a proportionate reason for them to very remotely cooperate in the evil of abortion in receiving a COVID- 19 vaccine.

Since one cannot desire to participate in evil, if one makes a proportionate judgement to receive a COVID-19 vaccine, all things being equal, they should seek to receive the vaccine which contains the lesser of the two evils. Assuming all other factors are equal between the vaccines, including their safety, effectiveness, and availability, one should choose a vaccine that used illicit fetal matter only during testing over a vaccine that uses illicit fetal matter in the production of the vaccine. Since the Moderna and Pfizer vaccine both only made use of illicit material during the testing phase, the evil action of participating in a very remote way with the abortion that led to the creation of the HEK-293 line is complete and over with. However, since the AstraZeneca vaccine makes use of HEK-293 in the production of the vaccine, each time a new batch of the vaccine is produced, a new act of cooperation with the evil of abortion occurs.

Assuming all three vaccines are safe, effective, and available, Catholics, having made a prudential decision that they should receive the vaccine, should attempt to use the least evil means possible and thus should seek to receive either the Moderna or Pfizer vaccine. This requires that Catholics request that their medical provider do their best to acquire the Moderna or Pfizer vaccine instead of the AstraZeneca vaccine. Likewise, Catholic healthcare institutions, whose ministry should be “rooted in a commitment to promote and defend human dignity . . . to respect the sacredness of every human life from the moment of conception until death,”20 should do their best to procure the Moderna and Pfizer vaccines in sufficient quantity that they do not need to offer the AstraZeneca vaccine.

Further ethical concerns

The news that these vaccines appear to be highly effective in preventing the COVID-19 virus is welcome news for many, but the excitement must be tempered by the reality that these vaccines are still in the experimental phase. Due to the speed at which these vaccines have been produced and the lack of time for extended trials, these vaccines will only be approved for Emergency Use Authorization (EUA). “An EUA is a mechanism to facilitate the availability and use of medical counter measures, including vaccines, during public health emergencies, such as the current COVID-19 pandemic.”21 Rather than requiring the usual substantial evidence of the safety and effectiveness of the vaccine, the FDA, in granting EUA, allows vaccines to be used in emergency situations as long as their benefits are likely to outweigh their risks.

Since all three of these vaccines are still experimental, any information about the safety and effectiveness of the vaccines are simply projections based on a small sample size. The choice to receive a COVID-19 vaccine is thus a choice to become a part of an experiment and “no one should be the subject of medical or genetic experimentation, even if it is therapeutic, unless the person or surrogate first has given free and informed consent.”22 This informed consent requires that the patient be made aware not only of any known risks, but also the understanding that the vaccine may involve risks to the subject that are currently unforeseeable.23 When deciding if someone should receive a COVID-19 vaccine they must make a further prudential decision as to if the risks and burdens of the COVID-19 virus outweigh the potential risks and burdens of the vaccine.

Even though the U.S. Supreme Court has upheld the right of states to mandate vaccines,24).] it would be highly inappropriate for the government or any institution to mandate the reception of a COVID-19 vaccine because no one should be forced to participate in experimental trials. The thought of forcing people to participate in an experimental vaccine should bring to mind the same concerns of some of the horrific mandated vaccines that Nazis forced upon concentration camp prisoners.

Certainly, there will be calls for the vaccine to be mandated on the grounds of the common good. Undoubtably, some will argue that unless the majority of people are vaccinated, this coronavirus will still wreak havoc on the world and thus it is in the Common Good for people to be vaccinated so the world can get back to normal.

When considering the Common Good, it cannot be forgotten that the Common Good extends beyond public health. The Common Good is “the sum total of social conditions that allow people, either as groups or as individuals to reach their fulfillment more fully and more easily.”25 Since the Common Good “is realized when economic, political, and social conditions ensure protection for the fundamental rights of all individuals and enable all to fulfill their common purpose and reach their common goals,”26 one must further consider other factors, including the spiritual, physical, and psychological goods of individuals and society.

While the Common Good must be considered, the common good of public health cannot outweigh a person’s right to have a religious or moral objection to receiving an experimental vaccine that is derived from illicit origins. Anyone whose concerns about these vaccines’ ties to aborted fetal material leads them to discern that they believe they cannot even be remotely associated with that evil, should recall the advice of the Pontifical Academy for Life and “take recourse, if necessary, to the use of conscientious objection with regard to the use of vaccines produced by means of cell lines of aborted human fetal origin.”27


After a tumultuous time in which the COVID-19 virus has caused extreme harm to many people across the world, the news of potential vaccines to prevent this coronavirus is welcome news. An ethical and moral analysis of three of these leading vaccines, produced by Pfizer, Moderna, and AustraZeneca demonstrates a need for Catholics to step back to evaluate the origins and nature of the vaccine before making a prudential judgement as to whether they should receive the vaccine or not.

Certainly many, including, perhaps the immunocompromised, elderly, and frontline COVID-19 workers, will make a prudential decision that the benefits of the vaccine outweigh the potential burdens of cooperation with evil and the experimental nature of the vaccine. Assuming these decisions have been made after proper prayer and discernment they should be respected. Others, perhaps younger and relatively healthy members of society, will make a prudential decision that the burdens of the cooperation with evil and the experimental nature of the vaccine outweigh the potential benefits of preventing them from becoming infected with the virus that has a mortality rate of .01% for those who are 25 years old,28 and likewise that discernment should be respected.

A close moral and ethical analysis of the three leading COVID-19 vaccines demonstrates that while they were produced with some use of illicitly obtained stem cell lines and they are still experimental, a Catholic can in good conscience make a prudential decision to receive the vaccine. At the same time, a Catholic can find moral and ethical objections to these vaccines which may lead them to make a prudential decision to forgo a COVID-19 vaccine. When making this determination, one must do so in light of the greatest commandment of loving God with all one’s heart, mind and soul while also loving one’s neighbor as oneself.29

With charity as the animating principle, Catholics and people of goodwill must consider the issues and discern for themselves whether it is prudential for them to receive the vaccine and then, also guided by that same animating principle, respect the decision of others, recognizing that each person’s situation is unique.

  1. “IHR Emergency Committee on Novel Coronavirus (2019-NCoV).” Accessed December 1, 2020. 
  2. Hannah Ritchie, Research and data: “Coronavirus (COVID-19) Cases – Statistics and Research.” Our World in Data. Accessed December 1, 2020. 
  3. Hannah Ritchie, Research and data: “Coronavirus (COVID-19) Deaths – Statistics and Research.” Our World in Data. Accessed December 1, 2020. 
  4. “Impact of COVID-19 on People’s Livelihoods, Their Health and Our Food Systems.” World Health Organization. World Health Organization. Accessed December 1, 2020.’s-livelihoods-their-health-and-our-food-systems. 
  5. Frequently Asked Questions about COVID-19 Vaccination. (n.d.). Retrieved December 01, 2020, from 
  6. “Coronavirus: Operation Warp Speed.” U.S. Department of Defense. Accessed December 1, 2020. 
  7. “Moderna’s COVID-19 Vaccine Candidate Meets Its Primary Efficacy Endpoint in the First Interim Analysis of the Phase 3 COVE Study.” Moderna, Inc. Accessed December 1, 2020. 
  8. “Pfizer and BioNTech Conclude Phase 3 Study of COVID-19 Vaccine Candidate, Meeting All Primary Efficacy Endpoints.” Pfizer. Accessed December 1, 2020. 
  9. “AZD1222 Vaccine Met Primary Efficacy Endpoint in Preventing COVID-19.” AstraZeneca, November 23, 2020. 
  10. Catholic Bishops Raise Concern Over COVID-19 Vaccine. (n.d.). Retrieved December 02, 2020, from 
  11. Annette B. Vogel, Isis Kanevsky, Ye Che, et al, “A prefusion SARS-CoV-2 spike RNA vaccine is highly immunogenic and prevents lung infection in non-human primates,” bioRxiv 2020.09.08.280818; doi: K.S. Corbett, D.K. Edwards, S.R. Leist, et al. SARS-CoV-2 mRNA vaccine design enabled by prototype pathogen preparedness. Nature 586, 567–571 (2020). 
  12. “Understanding MRNA COVID-19 Vaccines.” Centers for Disease Control and Prevention. Accessed December 1, 2020. 
  13. Vogel, Kanevsky, Ye Che, et al, “A prefusion SARS-CoV-2 spike RNA vaccine is highly immunogenic and prevents lung infection in non-human primates.” 
  14. van Doremalen, T. Lambe, A. Spencer, et al. “ChAdOx1 nCoV-19 vaccine prevents SARS-CoV-2 pneumonia in rhesus macaques,” Nature 586, 578–582 (2020). 
  15. N. van Doremalen, T. Lambe, A. Spencer, et. al. (2020). “ChAdOx1 nCoV-19 vaccination prevents SARS-CoV-2 pneumonia in rhesus macaques,” bioRxiv: The Preprint Server for Biology, 2020.05.13.093195. 
  16. Alex van der Eb. “USA FDA CTR For Biologics Evaluation and Research Vaccines and Related Biological Products Advisory Committee Meeting” (PDF). Lines 14–22: USFDA. p. 81. 
  17. Catechism of the Catholic Church, 2nd ed. (Vatican: Libreria Editrice Vaticana, 2012), §2274. 
  18. NCBC Ethicists, “Cooperating with Non-Catholic Partners,” in Catholic Health Care Ethics: A Manual for Practitioners, 2nd ed. (Philadelphia: NCBC, 2009), 265. 
  19. Instruction on Respect for Human Life in its Origin and on the Dignity of Procreation (Donum Vitae), (Rome: Congregation for the Doctrine of the Faith, 1987), 35. 
  20. United States Conference of Catholic Bishops, Ethical and religious directives for Catholic health care services, 6th Edition (Washington, D.C.: United States Conference of Catholic Bishops, 2018), 8. 
  21. Center for Biologics Evaluation and Research, “Emergency Use Authorization for Vaccines Explained,” U.S. Food and Drug Administration. FDA. Accessed December 2, 2020. 
  22. United States Conference of Catholic Bishops. 2018. Ethical and religious directives for Catholic health care services 6th Edition. Washington, D.C.: United States Conference of Catholic Bishops. Directive 31. 
  23. 16 CFR 1028.116 – General requirements for informed consent. 
  24. Jacobson v. Massachusetts (197 US 11 [Massachusetts 1905 
  25. Catechism of the Catholic Church, 2nd ed. (Vatican: Libreria Editrice Vaticana, 2012), §1906. 
  26. United States Conference of Catholic Bishops, Ethical and religious directives for Catholic health care services, 6th Edition (Washington, D.C.: United States Conference of Catholic Bishops, 2018), 8. 
  27. Pontifical Academy for Life, “Moral Reflections on Vaccines Prepared from Cells Derived from Aborted Human Fetuses,” National Catholic Bioethics Quarterly 6: 2006, 548. 
  28. Andrew Levin, William Hanage, Nana Owusu-Boaitey, et al. “Assessing the Age Specificity of Infection Fatality Rates for COVID-19: Systematic Review, Meta-Analysis and Public Policy Implications,” medRxiv 2020.07.23.20160895; doi: 
  29. Matthew 22:36-39. 


Fr. Peter Fonseca, a priest of the Archdiocese of St. Louis, holds a MA in theology, MS in Bioethics, and MDiv. He serves as the director of continuing formation for priests, administrator of St. Theodore in Flint Hill, and bioethics consultant to agencies in the Archdiocese of St. Louis and the greater St. Louis area. He has presented at various conferences / seminars across the country and has contributed to local television and radio programs.30

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I am an Informed and fully practicing Roman Catholic

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