Godfrey Hardy once called out another statistician's faulty analysis of Mendelian genetics, writing:
"A little mathematics of the multiplication table type is enough..."
I wish to call out some fatally flawed amateur assumptions about herd immunity. Please stay with me, because this has lockdown relevance. Be warned that the binomial theorem seems counter-intuitive, but it's a corner-stone of mathematics.
At one time, I was between jobs, and I worked as a casual (supply) teacher. I was amused once to hear some of my charges discussing me on a bus. One claimed I was their science teacher, another knew me as a computing teacher, and another thought I was their maths teacher. The fourth said "Naaah, he's Angus' dad."