Development of an effective, safe and widely available vaccine for the novel coronavirus is deeply important, but its development should avoid unethical links to abortion, said pro-life leaders in a letter to the Trump administration.

“It is critically important that Americans have access to a vaccine that is produced ethically: no American should be forced to choose between being vaccinated against this potentially deadly virus and violating his or her conscience,” said the April 17 letter to Dr. Stephen M. Hahn, commissioner of the U.S. Food and Drug Administration.

“Fortunately, there is no need to use ethically problematic cell lines to produce a COVID vaccine, or any vaccine, as other cell lines or processes that do not involve cells from abortions are available and are regularly being used to produce other vaccines,” it continued.

The letter’s signers include Archbishop Joseph Naumann of Kansas City in Kansas, chair of the U.S. Conference of Catholic Bishops’ Committee on Pro-Life Activities; the heads of three other bishops’ conference committees; and leaders of many other Catholic and non-Catholic groups.

The letter comes after the release of the Trump administration’s gradual three-phase plan to remove restrictions on economic and social life while seeking to contain the coronavirus spread, especially spread to vulnerable populations. A coronavirus vaccine, if effective, could help prevent infection and speed economic recovery.

The letter’s signers “strongly support” vaccine development “as quickly as possible.” At the same time, they urged the federal government to “ensure that fundamental moral principles are followed in the development of such vaccines, most importantly, the principle that human life is sacred and should never be exploited.”

“We are aware that, among the dozens of vaccines currently in development, some are being produced using old cell lines that were created from the cells of aborted babies,” signatories said.

They cited the case of Janssen Pharmaceuticals, Inc, which has a “substantial contract” from the U.S. Department of Health and Human Services and is working on a vaccine produced using “ethically problematic cell lines.”

The letter encouraged other vaccine development that uses cell lines not linked to these “unethical procedures and methods.” These are in development by companies like Sanofi, Pasteur, and Inovio, they added, while also noting the work of the Iowa-based John Paul II Medical Research Institute.

The letter was copied to President Donald Trump, Vice President Mike Pence, and Secretary of Health and Human Services Alex M. Azar, II.

Besides Archbishop Naumann, other bishops signing the letter are Archbishop Paul Coakley of Oklahoma City, chair of the Committee on Domestic Justice and Human Development; Bishop Kevin Rhoades of Fort Wayne-South Bend, chair of the Committee on Doctrine; and Bishop John Doerfler of Marquette, chair of the Subcommittee on Healthcare Issues.

Signers include Russell Moore, president of the Southern Baptist Ethics and Religious Liberty Commission; Michael Parker, president of the Catholic Medical Association; Joseph Meaney, president of the National Catholic Bioethics Center; Ellen Gianoli, president of the National Association of Catholic Nurses, U.S.A.; Marianne Linane, director of the National Association of Pro-Life Nurses; Donna J. Harrison, executive director of the American Association of Pro-Life Obstetricians and Gynecologists; Michael P. Farris, president, CEO and general counsel at Alliance Defending Freedom; Travis S. Weber, vice president for policy and government affairs at the Family Research Council; Kristan Hawkins, president of Students for Life America; and Lila Rose, president and founder of LiveAction.

Catholic teaching acknowledges the right to well-formed conscientious objection to many legal mandates and medical procedures, while also emphasizing vaccination as a matter of public responsibility.

2005 document from the Pontifical Academy for Life considered the moral issues surrounding vaccines prepared in cell lines descended from aborted fetuses. The Vatican group concluded that it is both morally permissible and morally responsible for Catholics to use these vaccines.

The pontifical academy also noted that Catholics have an obligation to use ethically-sourced vaccines when available, and have an obligation to speak up and request the development of new cell lines that are not derived from aborted fetuses.

The 2008 Vatican document Dignitatis Personae strongly criticized aborted fetal tissue research. However, as regards common vaccines, such as those for chicken pox and measles, mumps, and rubella (MMR), that may be derived from cell lines of aborted babies, the Vatican said they could be used by parents for “grave reasons” such as danger to their children’s health.

In a 2017 document on vaccines, the Pontifical Academy for Life noted a “moral obligation to guarantee the vaccination coverage necessary for the safety of others… especially the safety of more vulnerable subjects such as pregnant women and those affected by immunodeficiency who cannot be vaccinated against these diseases.”