The strain of covid has mutated and is more contagious? What?

The common cold is very contagious, but not serious for most. COVID 19 is serious in many (look at the hospital numbers and deaths) but if the vaccine brings about herd immunity, it may render the new virus no more concerning than that. Ideally, from the virus's position, it needs to be contagious - get as many hosts as possible - but not deadly. Mutation to be less damaging to the host would be best for the virus.

At the moment added contagion is of concern, but long term need not necessarily be.