Could the COVID-19 vaccine adversely impact healthy protein reception?

Question

I'm not a health expert, just trying to understand possible long-term side effects of the vaccine, so if my terminology and thinking is off, feel free to correct.

The prominent vaccines right now are the mRNA vaccines that cause our cells to recreate the spike protein that the COVID-19 causing virus uses to bind to our lung cells' receptors. I'm fairly confident from my limited understanding that spike proteins (or all types of envelope proteins, generally) are specific only to viruses, which don't help our bodies in any way. However, my concern is that I can't find any evidence or articles that specifically confirm that our immune system won't start targeting healthy ligands, such as hormones, other proteins, or even pharmaceutical drugs assuming they may have a similar enough structure to the mRNA-manufactured spike protein.

For example, this article suggests that the the SARS-CoV-2 S protein "allows an enzyme called furin, which is made by many types of human cells, to do the first cut...ACE2 is present in many organs throughout the body and interfering with it may have side effects, so researchers want to avoid hitting the receptor", suggest that it is possible that a vaccine response could have negative side effects to possible enzyme uptake. The article was written long before the vaccine was developed, so unfortunately it doesn't have commentary about whether or not the vaccine has been proven to accomplish that end.

Is there any research, evidence, or information that someone can link to that helps put my mind at ease on this possibility?

Since mRNA vaccines are novel and haven't had long-term test results, I'm frankly worried that there may be implications for such vaccines that may be more dangerous to healthy young adults more so than the risks of even the virus itself.

Answer 1

You say:

I can't find any evidence or articles that specifically confirm that our immune system won't start targeting healthy ligands, such as hormones, other proteins, or even pharmaceutical drugs assuming they may have a similar enough structure to the mRNA-manufactured spike protein.

"mRNA-manufactured" is a red herring here. If the spike protein could cause such an auto-immune response you'd see it from any vaccine that uses the SARS-CoV-2 spike in any shape or form (e.g the classic protein-subunit vaccines that are in phase III trials), as well as from the SARS-CoV-2 virus itself.

Now it's true that the virus itself does cause an immune overreaction in some people but this actually leads to ARDS often leading to death--something that would be hard to miss in clinical trials of the vaccine.

Speaking of such auto-immune reactions, some have been observed from the vaccines, involving cosmetic facial fillers. You can't compare these to ARDS.

It is a more reasonable question if "long Covid" reactions could be caused by administration of the vaccine alone, but again "long Covid" symptoms from the actual virus don't take months to emerge, even though various symptoms do persist that long. (I'm actually not sure how quickly the reactions observed in those with cosmetic facial fillers actually subside--maybe you can ask a more focused q on that.)

Furthermore, consider that phase II or III trials for the vaccines have been done for roughly 6-9 months now... (Actually, the FDA advisory on facial fillers is based on the two or so people who had them among the tens of thousands in the phase III trials. Those reactions were actually in line with the reactogenicity more generally observed in the trials--see another answer of mine here which touched on that. Note that that might not actually be from the spike protein though.)