I don't think it's gonna be that hard. All cells that blood reaches were happily taking mRNA vaccine.

I hate to break it to you, but it will be substantially more difficult to target other organ systems. The liver is uniquely easy to target with our current vectors.

Right off the bat, the liver receives roughly a quarter of all cardiac output, either directly or second hand from the digestive organs. Additionally, the liver has a fenestrated endothelium which, while not completely unique in the body, uniquely allows molecules like lipid nanoparticles (LNPs) to access liver cells. Finally, the liver is the site of most lipoprotein processing, and LNPs can be designed to take advantage of the existing pathways to get the gene editing mRNA into the hepatocytes. All this is to say that if you have a genetic condition that primarily effects the liver, there's a lot more hope for treatment in the near term than for others.

Good lecture on the difficulties of finding appropriate platforms for delivering gene therapies to cells for anyone interested [1]

[1] https://youtu.be/6URTjoK58Yc

No they were not. A vaccine triggers an immune response, not a functional change.

mRNA vaccines are highly localized: you get a sore arm because most of it only gets taken up by muscle cells around the injection site, which spend some time producing the antigen and triggering a primary immune response (the inflammation aka the sore arm).

Still it needs to enter the cells all the same.

As for being localized it's true however after vaccine dose S proteins have been detected also in remote locations in the body because you can't make something 100% localized.

If you had an infusion that doesn't trigger immune system you could just increase the dose significantly, put it in the blood and most likely it would have reached all cells that blood reaches.

Last I heard those gene editing things lead to so called of-target edits, so they were basically corrupting random dna. Now in this case the baby would have died without this treatment so clearly benefits outweight the risks. But even then they probably want to have the dose be as low as possible.

But I'm speculating a bit here.

What I find interesting about the covid mRNA vaccine is I remember being sick in March 2020 and I can't remember being sick since.

I can remember getting a sniffle at night and waking up fine the next morning a few times.

I think I had two doses of covid mRNA vaccine.

I have actually forgot what it is like to be sick. It almost feels like the covid vaccine gave me some kind of super immunity. I never get the flu shot either. I have not had the flu in 5 years for sure.

I think this is more likely a result of increased standards of cleanliness that have remained

It is caused by a missing enzyme in the liver, yes.

Specifically it is this: https://en.wikipedia.org/wiki/Carbamoyl_phosphate_synthetase...

People born with this lack the enzyme CPS1, which screws up the urea cycle and causes a build up of ammonia. Ammonia build up is bad for your nervous system.

You are right, current CRISPR systems tends to accumulate in the liver. Most CRISPR companies have shifted their focus to the liver over time because it's easiest to deliver there. Most viruses people use to target other organs are not large enough to carry CRISPR and lipid nanoparticles with CRISPR seem to like ending up in the liver and are hard to deliver at dose to hit other organ systems. It has been one of the big struggles of CRISPR companies. That being said, this is a huge deal and very encouraging.

As to the FDA stance, it tends to be more willing to go ahead with compassionate uses like this when it's clearly life or death.[1]

[1] https://www.statnews.com/2025/05/15/crispr-gene-editing-land... This discuss a little of the FDA stuff but not much more detail, it sounds like they did let them skip some testing.