[tiwil]

The vaccines from Pfizer-BioNTech and Moderna are both mRNA-based, i.e. they contain the messenger-RNA (RiboNucleic Acid) of the Covid-19's 'spike' protein. When injected into the patient bodies will end up translated into the SARS-CoV-2 spike protein by our cells and, because its a 'foreign' protein, will trigger the sought-after immune response: ...

Thanks for your information @fChk. And all info by @fChk is correct. Pfizer and Moderna uses mRNA of the virus, this is a new "technology" invented. Well, everything, I believe, is the same as I described before, except our body will need to build up the virus themself, but not dangerous at all.

mRNA, like its name, is a messenger that contains information how our body should make something. Then our body make it, and detect it as a foreign protein. Then our body will make that newly created foreign protein as "punching bag" as I said before. Everything from that points remain the same. Our body will know which part to attack when it receives real virus.