Looking at measles alone - the death rate in Samoa was 14.3 per 1,000 children infected, 1.43%.
World population is 7.8 billion, 25% aged under 15
https://www.indexmundi.com/world/age_structure.html
That is almost 2 billion kids.
Prior to vaccination, infection in childhood was almost universal and >90% of people were immune by aged 15
https://www.cdc.gov/vaccines/pubs/pinkbook/meas.html
Let's assume that only 90% of those kids under 15 would get measles, and that 1.43% would die (I accept that death rates would be lower in Australia, but higher in Africa, for example). That is 28 million dead kids under 15, or an annual rate of about 2 million.
That is just measles. Smallpox was much more deadly.
So when I say that vaccination saves millions of lives annually, I am being conservative.
