In recent weeks, I have encountered scores of people who are confused about Church teaching with regard to the morality of taking COVID-19 vaccines.

This confusion comes not really because they have not heard that Pope Francis, two Vatican organs, and the US Conference of Catholic Bishops have all said that it is morally permissible to receive them. It is mainly because several prominent figures -- a few well-known bishops, various priests, and several lay Catholic media personalities -- have undermined that teaching by publicly asserting that getting vaccinated is immoral.

In so doing, they have essentially said that the Church's well-established principles on cooperation in evil are not valid in the case of vaccines tainted in any way by the use of cell lines derived from abortions and that St. John Paul II, Pope Benedict XVI, and Pope Francis have all been in error with regard to their moral analysis of such vaccines.

Such a claim, especially from figures with a reputation for doctrinal orthodoxy, is scandalous. Beyond obfuscating the Church's position with regard to COVID vaccines, it renders papal judgments and formal Vatican declarations nothing more than erroneous opinions, something that cannot but undermine the teaching authority of the Church.

What are the principles of the Church with regard to receiving vaccines that in their development (J&J), production (J&J), or testing (J&J, Pfizer and Moderna) have involved cell lines derived from aborted fetuses? Since the Church emphatically condemns abortion, is it possible to benefit in any way from products derived from such an abortion, in these cases, one committed about 50 years ago?

This is the classic situation of cooperation in evil. The Church teaches that is always sinful to approve of a sin committed by another, which is called formal cooperation. More complicated is "material cooperation," when one occurs only in the bad action of the other without approving of the evil. Such cooperation can be morally permissible when the action is good or indifferent in itself and when there is a reason for doing it that is both morally good and proportioned to the seriousness of the other's sin and to the closeness of the assistance provided to carrying out the sin.

Applied to the situation of taking vaccines that involve aborted cell lines, the action of taking a vaccine is in general good or at least neutral. There is a just reason: to protect one's own or others' health from a disease that has taken 3.3 million lives across the world. The assistance given to the original abortion by someone vaccinated today is nonexistent, since there is no evidence that doing so will promote other illicit cell lines. And the only thing that seems to be proportionate to the evil of abortion would be seeking to save innocent lives.

That is why the Church has concluded and taught that it is permissible to take the vaccines. At the same time, the Church stresses that it is of course wrong to create abortion-derived cell lines and for pharmaceutical companies to use them; that using vaccines benefitting from abortion-derived cell lines should be avoided when comparable alternatives with no connection to abortion, or less connection to abortion, are available; and Catholics and all those concerned for the sanctity of life should protest the use of tainted cell lines and advocate for the development of vaccines with no connection to abortion.

So the Vatican and the US Bishops have been clear that, under present circumstances, because of the seriousness of COVID-19, it is morally permissible to receive Pfizer, Moderna, and the J&J vaccines, with preference given to the first two where possible, and that this doesn't constitute formal or material proximate cooperation in the abortions from which the cell lines involved in their development, production, or testing were derived. The Church also insists, however, on the duty to push for ethically untainted vaccines, and some are presently being developed.

What are the challenges?

Some think that the protest against tainted vaccines must be absolute. One well-respected bishop said that he could not in good conscience receive a vaccine even minimally derived from an aborted child and urged others to reject such vaccines. Our culture, he says rightly, has become habituated to the exploitation of aborted children. For that reason, he urged others with him to wait for ethically untainted vaccines in order to testify to the truth that abortion must be rejected in all its forms.

Others think that abortion is so evil that the theological principle of material cooperation no longer applies, because to permit any abortion-derived vaccine would contradict the Church's recognition of abortion as a grave moral evil. Abortion is so evil, one well-regarded bishop wrote, that any connection to an abortion, however remote, is an immoral cooperation with one of today's greatest crimes and cannot be accepted by a Catholic with a well-formed conscience.

One cannot but give God thanks for these bishops' profound pro-life convictions. At the same time, however, it is necessary to state, emphatically, that theirs is not Church teaching. A pro-life intention does not render every moral judgment that person makes infallible. It doesn't allow one to overturn the Church's principles with regard to cooperation in evil, which were formulated precisely to apply to situations of moral atrocities like abortion. And it does not allow one to presume a position of pro-life superiority to St. John Paul II, or Benedict XVI, or Francis.

That said, while receiving a COVID vaccine is permissible, it is not a strict moral obligation. One can in conscience voluntarily refuse. Some may also need to decline vaccines because they are allergic to one of the ingredients or have a severely compromised immune system.

At the same time, there is a duty to protect one's health and to protect others, especially those who are weakest and most vulnerable. That's why the Church says that if one chooses not to be vaccinated, then out of love of neighbor and pursuit of the common good, that person must do his or her utmost to avoid becoming means for the transmission of COVID to others.

Charity is the context with which to understand Pope Francis' words in a recent interview, "I believe that morally everyone must take the vaccine. It is the moral choice because it is about your life but also the lives of others." Christians are called to love one another as Christ has loved us. If the Good Shepherd laid down his life to save the lives of his sheep, Pope Francis is implying, we should be willing to take a vaccine if doing so might save the lives of one or more for whom COVID might prove lethal.

So, while the decision to be vaccinated should be voluntary, the proper use of freedom should always be tied to love. Therefore, under ordinary circumstances, the case to be vaccinated against COVID-19 seems stronger than the case against.

That does not mean that governments should compel citizens to be vaccinated, since it is possible, like the bishops cited above, to have conscientious objections. But conscientious objection, which must be protected, does not make one immune from consequences of such decisions, like in the case of "local mandates" at schools, or hospitals, or certain business settings: one cannot be forced to receive the vaccine, but neither can such settings be forced to accept someone who is not vaccinated, if they determine that doing so is contrary to the common good.

In the midst of many questions surrounding COVID-19 and vaccines, the Church has worked hard to provide clear -- even if sophisticated and highly nuanced -- answers. It is important for Catholics who think with the Church to put in the time to listen to the authentic voices and to study Church teaching so that we may radiate true light to others at a time of confusion.

- Father Roger J. Landry is a priest of the Diocese of Fall River, Massachusetts, who works for the Holy See's Permanent Observer Mission to the United Nations.