How are you going to stop virus mutation?
Flu mutates every year and the viruses are tweaked, every scientist I've heard is pretty confident that this will be possible with covid too
You can't stop mutation but you can slow the rate of mutation @Ch3rish. Mutations occur because of replication errors (that tends to be at constant ready for a specific virus) or DNA/RNA from another virus getting mixed in when someone has a concurrent infection. So say the right conditions for a successful mutation occurs in 1 in a million infections. If you have 1 million people infected per month, that is 1 new mutation per month. If you have 1 million infections per day, that is 1 new mutation every day... That is why case numbers are as important as hospitalisations/deaths.
If we don't slow the mutation rate it could overtake the speed that we can tweak the vaccine and the chance of a worse variant evolving is more likely because if people are immune to more benign variants from vaccination but not the severe variant, the more new variant will be selected for.
Flu is different because it is much less transmissible and many people already have natural immunity or are vaccinated. You don't need as many people to be immune to prevent the spread of flu.
We all understand a bit about R numbers now. Flu has an R0 of 1.2. SARS-CoV-2 has an R0 of 3+. You need to reduce the R number to less than 1 to stop an outbreak (by social distancing, hygiene practices, vaccination, natural immunity etc). It's a lot easier to do that if the starting point is 1.2.
It might not be possible to achieve herd immunity with the current vaccines because they do not give total sterilising immunity, you can still get the virus and transmit it. What we can achieve is a situation similar to flu, significantly reducing deaths, severe illness and the number of cases, slowing the rate of mutation so we can produce new vaccines to stay in the same stable position long term. The problem is getting there.
There is a risk, until we get to that point, with having only a small percentage of the population vaccinated and high case numbers that we are "selecting" any new variants that the vaccine doesn't work for. Therefore, we need to slow the mutation rate by reducing case numbers. The only way to do that is by preventing transmission by social distancing until the reduction in transmission from vaccination is greater than that from social distancing and there are very low case numbers.
It's a balancing act. As is balancing the economy with public health but, long term, the effect on the economy will be worse if we miss the opportunity to get to that point now and are back to square one in a few months because there is a new vaccine resistant variant.