Vaccines and fetal cells

Johnson and Johnson’s (J&J) emergency authorization has caused quite the hoopla in some circles. For some, the origin of cells is a significant moral issue.

In order to dive into this, we need a baseline understanding of this type of vaccine.

Vaccine Make-up

Adenovirus vaccines (like AstraZeneca, J&J or vaccines for Ebola and Hep A) have three components. I’ve talked about this before in detail. But, in short, the vaccine needs:

1. Instructions: The vaccine needs to tell what the body to do. This vaccine tells cells to make the COVID19 spike protein.

2. A carrier: Scientists insert the instructions into a carrier. The carrier is another weakened virus called an “adenovirus”. Adenoviruses are common viruses that typically cause colds or flu-like symptoms.

   

   Figure from NYT

3. A pathway: Finally, scientists need to choose one of two paths for that vaccine to replicate in the body.

Figure from Nature

However, we need to do a few things before throwing these three components into a vaccine vial…

Creating the Vaccine

We need to modify the adenovirus (i.e. common cold virus) to hold the instructions. We do this in three steps:

1. Remove a gene or two from the adenovirus so it can’t replicate in our body. We don’t want to get colds after we get the vaccine.

2. Replace that deleted spot with a SARS-CoV-2 gene for the “spike protein” (or the instructions on how to fight COVID19).

3. However, we still need those deleted pieces (from #1) in the vaccine. So, we create cells that contain those deleted pieces. For the AstraZeneca vaccine, cells came from a family (or cell line) called “HEK 293” (293 for short). For J&J, we used cells from the “PER.C6” cell line. These cells are the culprits for the hoopla.

What does this have to do with fetuses?

The cells that carry the deleted pieces were first isolated back in the 1970s and 1980s from aborted fetal tissues. Fetal cells were originally collected because of their ability to be maintained in the lab. (I really like THIS webpage that explains why use fetal cells in the first place). As time went on, we developed techniques to transform these cells into immortal cell lines that can grow indefinitely. The AZ and J&J vaccines do not have fetal tissue in them.

Other vaccines use this science too

• Moderna and Pfizer COVID19: Cell lines allowed researchers to test the mRNA-based vaccines and prove that they worked. Cell lines were not used to produce the vaccines.

• Cell lines were also used to produce the hepatitis A, chickenpox and shingles vaccines.

Bottom Line: In adenovirus vaccines, cells that carry the deleted piece have ancestors from fetal issue. They do not use actual fetal tissue today. The science was developed more than 50 years and, since, has saved millions of lives.

Love, YLE

Special thank you: I wanted to be sure I got this correct, so I consulted a brilliant microbiologist/immunologist who happens to also follow YLE. He volunteered to proofread my “translation” and he provided critical suggestions (all on a Saturday night).