Thread by @Brick_Suit

I'll give this a shot,

Mutations will happen no matter what.
If no vaccine is deployed, the new viral variants are still competing against the original virus to find hosts.
If a vaccine is deployed that only affects the original virus, the new variants have less competition

https://twitter.com/ScottAdamsSays/status/1429800907869331456

So it's not that the vaccine "causes" new variants to emerge. What it does is create a situation where the new variant is able to infect more people than if no vaccine had been deployed.

Assume 99% of a virus in a population is original and 1% of a virus is a variant.

These two versions compete against each other to infect new hosts. This competition inhibits the new variant's success in increasing the percentage of the population it infects.

Now assume a vaccine is deployed that only affects the original virus and not the variant.

As the vaccine is rolled out the spread of the original virus in the population is reduced. This reduces the competition the variant faces to find new hosts.

Over time, this allows the variant to become the dominant strain much faster than if no vaccine was deployed.

This can be good if the new variant is less lethal overall.

Or it can be bad if the new variant is more lethal.

An added variable is that the variant can spread at a different rate than the original.

If the variant spreads significantly faster it would become more prevalent over time without a vaccine.

If it spreads significantly slower it would become less prevalent without the vax