Must Catholics choose Moderna or Pfizer over Johnson & Johnson vaccine?

The USCCB issued this statement on vaccines:

“Pfizer and Moderna’s vaccines raised concerns because an abortion-derived cell line was used for testing them, but not in their production. The Johnson & Johnson vaccine, however, was developed, tested and is produced with abortion-derived cell lines raising additional moral concerns. The Congregation for the Doctrine of the Faith has judged that ‘when ethically irreproachable Covid-19 vaccines are not available … it is morally acceptable to receive Covid-19 vaccines that have used cell lines from aborted fetuses in their research and production process.'[1] However, if one can choose among equally safe and effective COVID-19 vaccines, the vaccine with the least connection to abortion-derived cell lines should be chosen. Therefore, if one has the ability to choose a vaccine, Pfizer or Moderna’s vaccines should be chosen over Johnson & Johnson’s.” USCCB

First of all, do NOT choose Pfizer over Moderna, and do not choose either Pfizer or Moderna over the Johnson and Johnson vaccine. The Pfizer vaccine is the least safe, then Moderna, and the most safe vaccine is the Johnson one. They are absolutely NOT equally safe.

The doctrine of cooperation with evil is a definitive teaching of the Roman Catholic Magisterium. As such, it has greater authority than a judgment of the prudential order of local Bishops or even of the Holy See. So the faithful may apply the moral principles taught by the Church, and may reach a decision of the prudential order, in that application, which is different from that prudential judgment made by the Holy See or the USCCB. This article applies Catholic teaching on morality and arrives at a different prudential judgment.

In Catholic ethics, we are not obligated morally to choose the action that does the most good or the least harm. We are morally able to choose among any and all morally permissible acts. If I have free time on Saturday, I could join a local prolife protest, or I could spend time with family or friends. The former is perhaps more virtuous and does more good. But I am free to choose among any moral acts. This implies that I am not morally obligated to choose the vaccine that has the most remote connection to a past abortion. As long as the reception of that vaccine is moral, I may choose it.

When determining the morality of an act under the principle of double effect or the principles of cooperation with evil or otherwise, an act is moral if it has three good fonts. Given two different acts, both of which are moral, we are not obligated to choose the act that has the least connection to abortion or to a sinful act by other persons. If that were true, then in our decisions in life, we would be constantly unable to take most courses of action, as cooperation with evil is very common in this life. There is no moral principle taught by the Church that if two different acts both have some type of remote material cooperation with a sin, one must choose the more remote act. That is false. No such teaching exists.

For example, in a just war, the nation defending itself can use any moral act. It is not obligated to constantly choose only those moral military actions which do the least harm and the most good. If so, then the enemy could anticipate which acts the defending nation would perform. Also, the defense of the nation would be gravely harmed, as many moral actions would be prohibited as being moral acts of remote material cooperation which are not the most remote possible. (To the contrary, sometimes even proximate material cooperation is moral.)

If there are two military targets that could be bombed in a just war, the military command is not morally obligated to bomb only the target that has fewer anticipated civilian deaths. As long as the good consequences outweigh or equal the bad, either or both targets may be attacked in the war.

What determines the morality of a cooperative act is the three fonts of morality. If you have only good in your intentions, and your act is inherently good, then the act is morally permissible if the reasonably anticipated bad consequences do not morally outweigh the reasonably anticipated good consequences. There is not a fourth font of morality, which compares all available good acts, and prohibits every good act that is not the most good.

The Pfizer and Moderna vaccines (mRNA vaccines) have been tested using aborted fetal cell lines (AFCLs), while the Johnson & Johnson and the AstraZeneca vaccines are each produced using AFCLs. So the latter has a less remote connection to the single abortion that originated a cell line, as compared to the former. However, AFCLs do not contain any cells from a fetus. They are thousands of cell divisions (cell-generations) subsequent to any fetal cells. This makes the acts of testing, producing, distributing, and receiving either vaccine so remote as to have very little bad consequences. Therefore, the good consequences of protecting life in the present day and reducing suffering (for those who might get sick and live) far outweigh the harm of this remote connection to a past abortion and a past act of taking fetal cells for research. I can’t think of an act using AFCLs that would be immoral, given the great remoteness of the past abortion (which was not committed for the sake of the research), and the good of medical research in general.

What makes a cooperative act immoral is not the gravity of the original act. Some persons have opined that abortion is so evil that no cooperation can be moral. That assertion rejects the definitive teachings of the ordinary universal Magisterium on morality. Three good fonts make any act moral. The cooperative act in no way promotes abortion, nor is it in any way associated with a present-day abortion. The only reasonably anticipated bad consequences of using these types of cells is the possibility that researchers might initiate a new cell line. But no new cell line of this type has been created recently. And new lines can be created, at this point in time, using adult cells and the moral technique called induced pluripotent stem cells. So the use of AFCLs in a vaccine is not likely to cause that bad consequences either.

Honestly, I cannot see any reasonably anticipated bad consequences of using AFCLs. The original act by which they were obtained was immoral, specifically taking fetal cells for research. The original abortion would have occurred in any case. But the cell lines today are so distantly related at to have no bad consequences of any significant moral weight. So I don’t see any reason not to use AFLCs in medicine.

And to add to the difficulties of fighting the pandemic, opposition to moral and safe vaccines (Johnson & Johnson; AstraZeneca), is itself of questionable morality. The real decision between different available vaccines is which has the greater safety record and which is most effective. And they are not equal in this regard. In trials, the Johnson vaccine was 100% effective in protecting the vaccinated from death. By comparison, there have been some deaths of elderly persons (and even a few middle aged persons) linked to the Pfizer or Moderna vaccines.

We must also consider that the abortion related to the cell line would have occurred in any case. So the immoral act which is related to the cooperative act (of making or receiving vaccine) is the use of aborted fetal cells for research, more so than the abortion. Taking the cells from the aborted fetus is proximate material cooperation with the abortion (as the abortion would have occurred in any case). And using a cell line, which originated in this manner, is remote material cooperation with the proximate act. The present-day acts are even more remote from the abortion than from the act of taking fetal cells for use in research. Both original acts are gravely immoral, but the taking of the cells is the less sinful of the two acts (i.e. the abortion and the original taking of fetal cells for research).

In addition, different vaccines also use different cell lines, with different lines originating in the 1960s, 1970s, or 1980s. Are we morally obligated to choose the vaccine which has a more remote connection to abortion in time, i.e. the cell line which originated longer ago? This is a serious question, as it would be possible for a new cell line to be created in order to test or make a vaccine. And such a plan would be substantially less remote. The answer is that, if the reasonably anticipated bad consequences do not morally outweigh the good consequences, and the other two fonts are good, then the act is permissible. We are not obligated to use the vaccine based on the less recent AFCL.

It is moral to receive the Johnson & Johnson vaccine or the AstraZeneca vaccine, even though each is produced using AFCLs. None of those cells were ever in a fetus. They are a cell line thousands of cell divisions subsequent to the original fetal tissue. The connection to the original sinful acts of an abortion and the taking of fetal cells for research is very remote in any case. And the moral weight of the use of a vaccine to protect life is far greater. Therefore, these vaccines are moral. We are never morally obligated to perform the most moral act, nor to avoid acts that are less moral. As long as the chosen act is morally permissible, we may choose the act.

USCCB: “if one can choose among equally safe and effective COVID-19 vaccines”

I do not judge that the vaccines in question are equally safe. The Pfizer vaccine has about twice as many adverse events reported in the HHS Vaccine Adverse Events Reporting System, as compared to Moderna, and both have had Adverse Events reported of miscarriages subsequent to vaccination. These vaccines may possibly be the cause of these miscarriages, making them indirectly abortive. By comparison, the Johnson and the AstraZeneca vaccines are not known to have this association with miscarriages. By telling Catholics to get the Moderna or Pfizer vaccines, the USCCB is endangering the lives of the unborn, and all because the Johnson vaccine was produced using a cell line remotely related to a past abortion, while the other two vaccines were “only tested” using such a cell line. The difference between using AFCLs for testing versus for production is trivial. Both cooperative acts are very remote from the original sinful act. Therefore, other factors weigh more heavily in the circumstances of the act.

Women who are pregnant or who may become pregnant should not be vaccinated with either the Moderna or the Pfizer vaccine. They should instead take vitamin D supplements and practice safety measures such as wearing masks, social distancing, etc.

In addition, the Moderna and Pfizer vaccine have had Adverse Events reported of Bell’s Palsy, severe allergic reactions, and some deaths of adults that may be related to the vaccination. Telling Catholics to get these vaccines instead of the Johnson vaccine, which at this point seems to have fewer adverse events, is an incorrect moral judgment. There is a greater risk of harm or death from the supposedly more moral vaccines, especially for the elderly, and there is a risk of miscarriage for pregnant women.

The USCCB should have investigated the safety of the Moderna and Pfizer vaccines before making such a statement, that those vaccines are the moral choice because they are more remotely related to a past abortion. That is NOT how morality is determined. Instead, ALL the consequences of the act must be considered, including the risk to health and life of the mRNA type vaccines (Moderna; Pfizer) which are newer and less tested, versus the lower risk of the viral vector type of vaccines (Johnson; AstraZeneca) which have a longer history of use and safety.


If an act is moral, then the faithful may choose that act. The faithful are not morally obligated to investigate the testing and production of every medication and choose the version that has the least remote connection to any sin. And abortion is not the only act that weighs in the font of circumstances. The safety of the different vaccines is much less remote and so has much greater moral weight. And it is arguable that the Johnson and AstraZeneca vaccines may be substantially safer.

It is shameful that the USCCB made the above discussed recommendation without considering the harm done by the Moderna and Pfizer vaccine by miscarriages and by the increase in risk of death to the elderly. If the vaccines are the cause, which is a real possibility, then recommending those vaccines might kill some prenatals and adults in the present day — all because of a very remote connection to a past abortion that is not affected by acts in the present day (and would have occurred in any case).

Abortion is not an idol to be worshiped. The teachings of the Church on morality do not change when considering abortion, as opposed to other intrinsically evil and gravely immoral acts. The teachings on cooperation with evil also do not change when abortion is involved.

I will be waiting for the Johnson and Johnson vaccine. I’m also not recommending the Moderna or Pfizer vaccine to friends or family.

Note: Here is an article on a statement from a group of Catholic ethicists who state that the currently available vaccines (including AstraZeneca) are morally equivalent because each has a very remote connection to a past abortion.

Ronald L. Conte Jr.

1. Congregation for the Doctrine of the Faith, “Note on the morality of using some anti-Covid-19 vaccines” (17 Dec 2020), no. 2.

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1 Response to Must Catholics choose Moderna or Pfizer over Johnson & Johnson vaccine?

  1. Michael says:

    I registered with the county Department of Heath where I live to secure a place on the waiting list to receive a Covid vaccination as that’s the way it’s done here. After months of waiting, I was finally contacted via automated text message to verify that all the information I initially submitted was still correct or give me an opportunity to update it. A couple weeks later, I was contacted again via automated text to choose a time and location to be vaccinated from several openings that were offered. After making my selections, I received a confirming email, and in it was then informed I would be receiving the Pfizer First Dose vaccine on the date and at the location I specified. At no point was I given the option to choose a vaccine manufacturer, or was it even made known to me which one I would receive until I received the confirming email for my appointment. I shared my experience for the benefit of readers who don’t have the luxury of picking and choosing which they think is safest, or best for whatever reason. Many of us are just thankful for the chance to begin building immunity to this deadly disease for our own protection, and just as importantly protecting those we come into contact with.

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