> if you don't analyse something over 10 years, you don't know its effect over 10 years

Yes, that is why long term studies are done. Vaccine as a methodology has been proven effective. Many diseases are non-existent now thanks to it.

My knowledge is limited with respect to COVID vaccines but if they are any thing like the vaccines developed for flu strains then they will not have any adverse impact.

>By using a variety of different vaccines all over the world the expression of humanity is that we are spreading the risk among various vaccine types or contracting COVID itself.

"spreading the risk among various vaccine types" could you elaborate on this?