Questions I really want answers to

[Penguin54]

I've read the following, or something like it, on loads of sites "mRNA vaccines work by providing the genetic code for our cells to produce viral proteins. Once the proteins, which don’t cause disease, are produced, the body launches an immune response against the virus, enabling the person to develop immunity." I'd like some answers, are there doctors out there that know about these things?

Question 1: the proteins are produced by cells that presumably go on to replicate, with the mRNA changes incorporated in their replications. Then the replicated cells produce more viral proteins, which our immune system will presumably attack. What happens when the number of modified cells is producing enough viral protein to overwhelm the immune system?

Question 2: Why does the body launch an immune response to something that is produced by our cells? Why does it not recognise that the viral proteins are produced internally, and so should not be attacked?

Question 3: If the immune system is attacking viral protein, what will it do when it sees, not just the “spike”, but the whole virus?

Question 4: What will happen when someone who has had the vaccine, and so is producing viral protein, is trying to conceive a child with someone who hasn’t had the vaccine, so may recognise the other person’s sex cells as “foreign” and attack them?

Looking for answers

There are knowledgeable folk in the coronavirus Data threads OP, I suggest posting there and asking.

There is also public advice about being vaccinated when TTC. I don't think there's an issue but have no idea as to the reasons.

Hello! I'm a biologist. Here are your answers:

1. Normally your cells produce mRNA by reading your DNA. There is no DNA in the vaccine to be incorporated back into your own cell's DNA, so you won't continue to produce the viral mRNA sequences.

1. The body recognises the viral proteins produced by your cells as viral. All of your cells are covered in human proteins, but these are different to viral proteins and so aren't attacked by the immune system.

1. The first part of the real virus that the body would see is the spike protein on the outside of the virus. That's why your immune system recognises that as the virus and attacks. The viral protein made by your cells following the vaccine is the same spike protein, tricking your body into learning to attack that protein and in turn the real virus.

1. To be honest I'm not even sure if vaccines can be taken up into sex cells, but no cell will continue to produce the viral proteins for very long at all. The immunity gained from vaccines is gained from antibodies and specialised attack cells that your body creates in response to the vaccine.

I hope that helps but feel free to ask anything and I'll do my best to answer.

PlantDoctor, thanks very much! Some good information in a format that a layman like me can understand. I may come back with further silly questions, but you have gone a long way to broadening my understanding. Thanks again!

mRNA is rather like sending someone a coded letter. The cell decodes the mRNA and produces the protein - that's the end of the mRNA - it doesn't replicate, but now we have a bunch of cells with this protein in them. I don't know precisely how long the mRNA itself survives in the body, but remember it's only viable when stored at incredibly cold temperatures, so I suspect it's destroyed within hours of entering the body. At this point you have a bunch of this harmless protein knocking around.....

Your immune system doesn't differentiate regarding the SOURCE of an impurity. Viruses themselves populate the body in the same way - they infect a cell and change its behaviour so that it produces more viruses which go on to infect further cells etc.

The whole point of using this protein is that it is target training your immune system. When it comes across a whole virus, it spots immediately the shape it's been trained to attack and goes into action.

As far as the protein goes, it will either be naturally shed from the body over the next few days, or destroyed by antibodies.

So to your final point - the only biological interaction between two sex partners is when the sperm meets the egg. The sperm has no immune system and I'm fairly certain it's incapable of transporting the particular protein over. If you happened to have sex within a day of having a vaccine AND some mRNA had made it's way into the sperm (highly unlikely) and the sperm interacting with the egg had some of this protein (more unlikely) then all that would happen is that the protein would be destroyed by the female's immune system. Worst case scenario is the sperm is destroyed and the implantation fails... happens all the time for millions of other reasons. Maybe another sperm succeeds then. Maybe you try again tomorrow.

It's a no brainer - if you're concerned about an impact on fertility or an existing pregnancy, the virus is a FAR FAR greater danger than any vaccine. No vaccine has ever been known to cause fertility issues because as I said above, it's biologically implausible for it to do so.

On the other hand, viral infections HAVE been known to cause fertility issues, and covid in particular is a virus that attacks a lot of the body's organs.