There is something that was discussed way earlier in the thread called the effective reproduction number (R0) which measures how easily the virus spreads.
It is well known the delta has a much much higher R0
There is actually a "magical number" for herd immunity and it is calculated as (1-1/R0). If R0 is 9 then 1-1/9 = 89%. That is where the 90% is coming from
With the original strain R0 was 3 ( 1-1/3 = 66% ) hence the original estimates.
Simple science. When you understand it, it really really helps accept and support some of the decisions being made rather than working oneself up based on false information.
Science is mostly based on logical observation and analysis. Mathematics are mostly to support ideas and theories, or the opposite. However, logic is simple and accessible to everyone, and it is the basis of any theory.
The argument that the Vaccine stops or reduce the spread falls apart when they are also required to follow the same hygiene procedures before their vaccination.
Of course, the second argument sweeps in to replace the first arguments: but it makes the virus less dangerous and prevents hospitalization. Well, the virus is dangerous for 4 or 5 % of the population only, so why should we all take the vaccine?
Revert to the first argument.....
We keep getting this silly circular arguments, and then try to complicate it by using formulas like above..
You can statistic anything you want, and use mathematics to complicate any issue, however, it is easy to spot what works and what does not.
When you see a Nurse, who has treated COVID patients, refuse the Vaccine on the basis of its safety, you really need to question what is being portrayed in the media.
We are an over-medicated society, we give pills to kids just for being kids (labelling them as hyper), and we have been tamed to just accept them as food.
Politicians want the easy way out, and think the Vaccine will provide it to them. They are afraid of the being labelled as not doing enough and lose their positions. It is understandable since most politicians are cowards anyway.
Is the Vaccine going to eradicate a Virus like COVID? I remember at the beginning of the Pandemic, all experts agreed that this kind of Virus cannot be eradicated as it mutates very quickly, and there is no way we can update as fast. I believe that somewhere along the way politicians realized that this line of thinking does not benefit them, and of course the big pharma companies. This mutual shared interest led to the situation we are in today: forcing a necessary Vaccine to only a small percentage of the population unnecessarily to almost all of the population using any means possible.