NEW YORK – The U.S. bishops’ conference is encouraging Catholics to get a coronavirus vaccination because it’s a “moral responsibility for the common good,” even if some vaccines are connected to abortion-derived cell lines.

“Given the urgency of this crisis, the lack of available alternative vaccines, and the fact that the connection between an abortion that occurred decades ago and receiving a vaccine produced today is remote, inoculation with the new COVID-19 vaccines in these circumstances can be morally justified,” said Bishop Kevin Rhoades of Fort Wayne-South Bend and Archbishop Joseph Naumann of Kansas City in Kansas in a joint statement.

However, the bishops noted the Moderna and Pfizer vaccines are more morally acceptable than the AstraZeneca vaccine if the option to choose presents itself. They focused on these three vaccines as the most likely to be available in coming months.

They cite the fact that AstraZeneca used an abortion-derived cell line in the design, development, production and confirmatory testing of its vaccine as reasons its morally compromised. The vaccine is reported to be 90 percent effective but is still pending approval from the Food and Drug Administration before distribution can begin.

“The AstraZeneca vaccine should be avoided if there are alternatives available,” the statement said. “It may turn out, however, that one does not really have a choice of vaccine, at least, not without a lengthy delay in immunization that may have serious consequences for one’s health and the health of others. In such a case, it would be permissible to accept the AstraZeneca vaccine.”

Bishops Rhoades and Naumann expressed less of a moral concern with the Pfizer and Moderna vaccines. Distribution of the Pfizer vaccine began Dec.13 nationwide. The Moderna vaccine is awaiting Food and Drug Administration approval. Both are said to be about 94 percent effective.

Neither Pfizer nor Moderna used abortion-derived cell lines in the design, development or production of its vaccine, but it was said to be used in a confirmatory test. That said, the bishops consider that connection “very remote from the initial evil of the abortion.”

“In view of the gravity of the current pandemic and the lack of availability of alternative vaccines, the reasons to accept the new COVID-19 vaccines from Pfizer and Moderna are sufficiently serious to justify their use, despite their remote connection to morally compromised cell lines,” Bishops Rhoades and Naumann said. “Receiving one of the COVID-19 vaccines ought to be understood as an act of charity toward the other members of our community.”

The National Catholic Bioethics Center also said it’s morally acceptable to take what it considers morally compromised vaccines, but said taking one must be done under protest.

“A person who discerns in conscience that he or she can take such a vaccine has an obligation to make known his or her opposition to abortion and the use of abortion derived cell lines,” the organization said in a statement.

The organization didn’t identify any specific vaccines. Instead, it created three categories based on companies use of abortion-derived cell lines in a vaccine’s development process. It noted that Catholics ultimately can choose for themselves.

“The Catholic Church neither requires nor forbids the use of ethically problematic vaccines, but instead urges people to discern what decision to make after having carefully formed their consciences about the moral and prudential issues surrounding the vaccines that become available,” the statement said.

Under the three categories, the most acceptable didn’t use abortion-derived cell lines at any point in the development process. The least acceptable used them in more than one phase of development. And the middle category used abortion-derived cell lines at one point of development – such as Pfizer and Moderna.

While Bishops Rhoades and Naumann encourage COVID-19 vaccinations, they want to make sure the use of a morally compromised vaccine doesn’t take away from the abortion issue.

“With this in mind, we should be on guard so that the new COVID-19 vaccines do not desensitize us or weaken our determination to oppose the evil of abortion itself and the subsequent use of fetal cells in research,” they said.

[Related: Vatican Will Offer Pfizer Vaccine Against COVID-19 to Employees]