> Actually (and this might sound crazy, but I encourage you to think through it and respond), why not apply this logic to COVID-19 vaccines, as well? The COVID

> Actually (and this might sound crazy, but I encourage you to think through it and respond), why not apply this logic to COVID-19 vaccines, as well? The COVID-19 vaccines train the immune system to attack the spike protein. A mutation that avoids this would successfully dodge the immune system… and not be able to latch onto and infect cells, because the same thing that makes the spike protein work (the shape(?) of the binding site(?)) is also the thing that makes the immune system attack it. It's theoretically possible for a SARS-CoV-2 virus to be so mutated (SARS-CoV-3?) that the spike protein is radically different, but in a way that just so happens to also work. However, that's unlikely – the immune system also pays attention to other bits of a virus (even though the mRNA vaccine doesn't), and in the unlikely event this happened, the immune system would probably be able to kill the mutated version without problems. But it could happen, if there are breeding populations of COVID-19 in people with weak / unprimed immune systems – for the same reason you need to take the full course of antibiotics, we need to get as many people as possible vaccinated. --- The important thing isn't medication. Do a heat treatment of some agar that isn't quite hot enough, and the bacteria will become heat resistant. Anything that provides selection pressure (kills some, but not all, of the population) can trigger evolution in the direction of “thing is less good at killing”. A single (mutant) heat-resistant bacterium will probably die in a 121°C pressurised steam environment, but might survive 5 minutes of an 80°C environment that most of its fellow bacteria die to. Then a substantial portion of the surviving bacteria twenty generations later (i.e. a million times more bacteria) would be heat-resistant descendants of this survivor, making the once-effective treatment much less effective. Also: bacteria can share DNA between each other, so if one becomes resistant, it can share its resistance with other bacteria. Viruses can't do this; viruses are almost inert outside cells, and it's unlikely that two different viruses will infect the same cell at the same time. (It does happen, though, with influenza, because there's so much influenza and, more importantly, several strains of similar-enough versions for a recombination to be viable.)