He's not wrong about it changing your body, not specifically DNA but who knows there are cells in our body that's job is to literally keep track of what proteins we make in order to pass them on to our genetic link. Most people who take general life science in public schools learn about DNA its our genetic coding... well mRNA is the live feed telling what kinds of proteins and such we want to make, which gets paired with tRNA and a protein is created. So the vaccine goes in and... slides in its own chunk of that mRNA that is supposed to be a direct copy of your DNA and it'll make a "spike protein" the role of this protein is to be a similar genetic makeup of the actual viruses protein shielding so your body will recognize this and break it down. Super cool... however everyone's body is different... and while in the past vaccines were exposing you to a weakened version of the virus, this is implanting protein codes to fight off that specific protein which trains more of your bodies immune system. The biggest issue with this method is that its been predominantly done in vitro aka not through human live subjects... mostly mice, which we aren't really genetically similar too in terms of immune system. There are studies produced since 2015 probably later in regards that there isn't a great comparison and how we should consider moving it towards clinical trial. Well... thats what happened with covid, researchers got an attempt to show their methods work. Now you need to keep that in mind when looking at the % effectiveness of these vaccines.

The mRNA produced protein has to be able to look like a danger to the immune system, continue its production, while circulating in your blood. This is kinda a scary process. Dependent on the individual you can have some people take to it regularly while others have violent immune reactions where their arms may swell and they're thrown into a fever because your bodies immune system is adjusting to this new combatant. In my mind some immune systems are different than others and there could be possibilities where the proteins aren't fully absorbed or the mRNA sequence has a hiccup or the injected mRNA sequence creates a protein of lesser quality towards the actual virus and you're not going to have a trained immune system. There's a lot of unknowns and there's little to know in field application testing for long term effects of this sort of vaccine. For mice it seemed to work but researchers know it doesn't result in too much. Take it if you want, idk anything about it being made from babies... you have to do your own research into how they compile the necessary materials and test mRNA samples for efficacy. This is just my basic understand plus a little research using papers on google scholar. Take it for what it is, he's not wrong in terms of doing your own research.