Vidqun,
The messenger rna (mrna) is killed off in a couple of days by the body and doesn't keep manufacturing spike proteins perpetually, which is what was suggested in a meme on Facebook which started this false opinion.
If you are concerned about the body over-reacting, maybe take a few moments to read a bit about cytokine storms.
This is what happens when your body overreacts to an invading virus and creates too many antibodies. It is especially dangerous in respiratory illnesses as it fills a person's lungs with fluid, causing the person's own immune system to drown them.
This is how people died during the Spanish flu.
For everyone saying, 'I trust my immune system to beat covid', yes, it might, but there is also a chance it won't cope.
There are risks with everything we do.