Ethical considerations should have a priority place in science and medicine. Promoting sound bioethics promotes confidence in doctors and scientists and their work, among peers, the public and policymakers. This is certainly seen in the recent ethically-guided decisions around federal funding of research with fetal tissue from elective abortions. Ethical guardrails help focus precious research funds on projects with best chance of success and benefit for all. Even in a crisis such as the current COVID-19 pandemic, illumination of the ethical vs. unethical proposals can educate and serve to focus attention and resources on the paths that will benefit all.

A recent count showed over 160 different treatments and vaccines under development to fight off the SARS-CoV-2 (CoV-19) coronavirus, with an estimated 115 vaccines under development, though the vast majority are only at the laboratory stage. None of the treatments or vaccines under development use trafficked fetal tissue from ongoing abortion in their production.

There is an ethical concern, however, with some of the vaccines under study, as their production uses human cell lines that were established from cells taken from electively aborted human fetuses. In particular, five of 16 vaccine candidates now in registered clinical trials or in early pre-clinical stages of development use cell lines developed from elective abortions.

Why do some vaccine schemes use these cell lines for viral vaccine production, while others do not? Remember that a vaccine is designed to expose the body’s immune system to a potential infectious agent before an actual infection occurs, flagging the offender for future recognition, somewhat like a “Wanted” poster. Part of that recognition is priming the immune system to be ready to repel a future invader, arming itself by producing antibodies that recognize the invader. The recognition signal (antigen) given in a vaccine can be the whole invader, e.g., a whole bacterium or whole virus, weakened or killed so as not to cause the actual infection. Alternatively, a part of the invader, such as an essential protein on the external surface of the virus or bacterium, can be used as the recognition factor (e.g., like a Wanted poster with a picture of a face but not the whole body of a person.)

So where do cell lines come in? For pathogens like bacteria (e.g., diphtheria, pertussis, tetanus), which are cells that can grow independently, no cell line assistance is needed as these can be grown in large numbers and then weakened, killed or taken apart to derive the vaccine recognition component. Viruses (e.g., influenza, polio, SARS-CoV-2), however, cannot replicate on their own; they absolutely require the help of a cell. The viruses infect a cell and hijack cellular production machinery to multiply within the cell.

Cell lines are used to grow whole viruses to be used in vaccines. The viruses grown in cell lines can be the actual infectious virus itself, or it can be a different virus such as adenovirus, genetically engineered not to cause an infection but also to carry a recognition factor, e.g., the gene for a protein of SARS-CoV-2. The origin of such cell lines then becomes the locus of ethical concern. Some cell lines (WI-38, MRC-5) derived from abortion have been used, and are still used, to grow whole infectious virus for some vaccines. Other cell lines (HEK293, PER.C6) are being used to grow genetically-engineered adenoviruses or to make large quantities of viral protein for study in the lab. Some may see no ethical problem in use of abortion-derived cell lines for vaccine production, but for many a straight line can be drawn from the ending of a human life in an abortion to a vaccine created using cells derived from an abortion. Even though the cells have been propagated for years in the laboratory, far removed from the abortion, that connection line remains.

Several questions of conscience then arise. For those aware of a vaccine’s lineage, one question is whether they can receive such a vaccine if offered. That possibility for conscientious objection by potential vaccine recipients also creates ethical demands on the policymakers, healthcare officials, scientists, vaccine creators and funders, whether or not they themselves have an ethical concern, because of the question of access to a vaccine by the entire citizenry in good conscience. This is especially true if alternative production methods and vaccines are possible for which there is no ethical question.

Among the vast number of COVID-19 vaccines under development, most raise no ethical questions regarding their production. There are numerous cell lines available for virus production as well as production of viral proteins, including insect cells, monkey cells and human cell lines which do not have an abortion-derived lineage. One example of a modern vaccine created in this way is the Shingrix (shingles) vaccine, created using a hamster cell line. Newer vaccine production methods are also being advanced for COVID-19 vaccine development, including creation of RNA and DNA vaccines which use no cells at all in their production. So there are, in fact, a tremendous number of potential COVID-19 vaccine possibilities which raise no questions of conscience regarding their production.

How soon any of these potential vaccines become available and which methods are eventually successful for effective vaccine production is unknown. But we can immunize our conscience now and encourage others to consider the ethics. Adherence to the highest ethical standards in science and medicine serves all humanity, because it values the dignity of every human life and respects the consciences of all.