1st 2 shots were developed for the original more deadly strain. It develops memory B and T cells that can provide protection for up to 50 years in some cases. Due to the new Omicron variant, the booster is required to improve immediate antibodies and increase T & B cells for long term protection from death and other nasty nasty things.
1 and 2 did work for the original strain they were developed for. Booster helps with subsequent strain.
As I said, you'd have to be pretty stupid to get 1 & 2 and not 3. There are a number of really stupid people here on HC. Really really stupid.
