“Just the Facts” on Vaccine Development

The U.S. Food and Drug Administration granted Johnson and Johnson (J & J) emergency use authorization for their COVID-19 vaccine on Feb. 27.

Unlike the Moderna and Pfizer vaccines, which are messenger RNA (mRNA) vaccines, the J & J vaccine uses a traditional approach to development.

While the effectiveness of the J & J vaccine is 66% versus the 94% and 95% of the Moderna and Pfizer, respectively, it appears just as effective at reducing hospitalizations and lowering the mortality rate.

Therefore, the ability to reduce mortality, along with a lower cost and the ease of storage, may cause the J & J vaccine to be the primary vaccine used in the future.

Shortly after approval, the Archbishop of New Orleans warned that “the latest vaccine from Janssen/Johnson & Johnson is morally compromised as it uses the abortion-derived cell line in development and production of the vaccine as well as testing.”

The Archdiocese of St. Louis made similar statements, followed by the United States Conference of Catholic Bishops reiterating the moral concerns detailed in its December statement.

Similar statements have been made by the Ethics and Religious Liberty Commission of the Southern Baptist Convention.

This caused some media outlets to generate headlines linking vaccines to abortion, so what are the concerns?

My ethics professor told me that good ethics starts with good facts, so let’s start there.

Immunologists must capture viruses for study and regrow them for vaccine development. While this process is complicated and time consuming, it can be summarized as follows.

The virus must be isolated and then replicated. Since viruses lack the cellular machinery to reproduce, they are dependent upon a cellular host.

Once a virus infects a host cell, it hijacks the host’s existing structures to replicate itself until it ultimately destroys the host cell. So, for scientists to grow a virus in order to study it, they need a lot of host cells.

After cells are infected with a virus, they are allowed to multiply and then they are weakened in order to limit or completely prevent their ability to replicate.

There are typically three stages of vaccine development.

1. Design and development during which host cells are used to replicate the virus in order to have enough to study and to develop an active or inactive vaccine.
2. Production when the vaccine is mass produced for lab testing and later public distribution.
3. Testing in which the effectiveness and safety of the vaccine is the focus, with researchers using host cells to generate sufficient data before moving to human trials.

So, where do we get all these host cells?

Immunologists initially used animal cells to develop vaccines because it was not possible at the time to culture mass amounts of human cells for manufacturing nor to confirm that available human cells were not tainted with an unknown virus.

The assumption was that using animal cells was safer.

This thinking changed in the early 1960’s when an estimated 10-30% of polio vaccines administered in the US were tainted with a simian virus that originated in the monkey host cells used in vaccine production.

This opened the door for a change in thinking about the use of human cells, but it was still difficult to acquire these in large quantities.

In 1961, Leonard Hayflick demonstrated that typical human cells grown in a culture will divide only 40-60 times – a discovery now known as the Hayflick Limit. In order to exceed this limit, cells have to be altered.

The only natural occurrence of this is due to cancer, which is the process that created the HeLa cells recovered in 1951 from Henrietta Lacks, a 31-year-old African American woman who died of cervical cancer.

These cells are still cultured in labs for research, but these cancer cells are not used for vaccines.

Therefore, scientists developed artificial means to deregulate the cell replication cycle and exceed the Hayflick limit. However, this process rarely works, and these cells, known as immortal cell lines, are extremely rare.

The original immortal fetal cell lines were not developed for the purpose of vaccine development.

When it was discovered that fetal cells do not experience as many replication cycles and were less prone to cancer and less likely to be subjected to unknown viruses, researchers adopted them for vaccine development.

Since the 1950’s and 60’s, countless vaccines have been developed based on these cell lines, including the polio, rabies, rubella, shingles, chicken pox and Ebola vaccines.

It is likely that during your lifetime that you have used multiple products that were tested or developed with one of these cell lines.

Often media headlines related to fetal cell lines are misleading, looking for sensationalism by equating a vaccine with the act of abortion.

While the cell lines were developed from leftover tissue following an abortion, the researchers’ intention was not to create a vaccine but an immortal cell line. It was only later that these cell lines were employed in vaccine manufacturing.

It needs to be clearly understood in this sensitive debate that none of the original cells still exist.

What is used in research functionally are clones of the original cells which have been grown, divided, frozen and grown again for the last 35-50 years. None of the original fetal tissue still exists.

In these immortal fetal cell lines, researchers discovered an efficient vehicle for growing and developing vaccines from human cells. What better way to research the impact a virus has on people or how a vaccine will work than to do so with real human host cells?

Often, like in the process that produced the J & J vaccine, the virus destroys the host cell and then the cellular remnants can be filtered out. In other words, the human cells used in developing the vaccine are not part of the vaccine itself.

So, what is the concern here? What makes the J & J vaccine different?

Unlike the Pfizer and Moderna vaccines, which only used fetal cell lines for the testing phase, J & J uses them at all three stages.

The concern of many religious leaders is the extensive use of these cell lines and that the use of them leads to support for the abortions that were linked to the cell lines decades ago.

This raises a number of moral questions.

Many of these fetal cell lines were not only developed from post-abortion fetal tissue but also from tissue that was acquired and studied without the mother’s consent. This is the case, for example, with the HeLa cells.

This leads to a whole other set of moral questions that demands a more reasoned approach given the ethical distinctions at play.

In light of the seriousness of this pandemic, we need to have less knee-jerk reaction to headlines.

We must start with “just the facts” before we determine what we believe and why.