1. Are there any vaccine ( of any Disease ) that are 100% effective? Or do we operate ( as I would assume ) something like 5 Nines effective rate and call it 100%?
2. Across all type of Vaccine, what are the average or median effective rate? i.e Should we expect Vaccine to be 90%+ effective in the first place? Or is that a wrong expectation to make?
3. What happens in the case of 10% ineffective, do they take a third dose?