There's one problem with that argument: vaccines do the exact same thing, i.e. they let your own immune system build up resistance to these diseases. They're not covering for your immune system or dealing with symptoms. Again, they stimulate the natural immune system response. That's just what we assume. Sure, you become resistant to that disease, but in reality, you're cutting your immune system slack, making it less efficient than what it should be. And yes, I assumed 99% of people wouldn't agree with me on my views of natural selection. If anything it's making your immune system stronger, getting a vaccination is like putting soldiers on some sort of training simulation before sending them into real combat