Did you see a small problem between the British government’s definition of herd immunity…and what it actually is? Herd immunity is — the real thing — what happens after enough members of a population have been vaccinated. It’s not…just letting an entire nation be rampaged by a lethal virus for which there’s no vaccine. […] The human species never developed “herd immunity” to polio or smallpox or any virus, really — ever, despite millennia of death and illness and misery. Why not? Because herd immunity depends on vaccines. We vaccinate a large number of people, and then all of us are protected, because transmission rates are reduced (among other things.) Let me make the point again. The human race never developed herd immunity to a lethal virus, precisely because herd immunity is not something that emerges naturally. What happens, instead, when we let a virus simply take its course? What happened with smallpox and polio: they just rampage through populations, forever.