By Melvin Bass

Since March of last year, Doctor Anthony Fauci, the CDC, and legions of other experts have repeatedly reminded us that we will achieve “herd immunity” when 70% of our population has been fully vaccinated. Simple math and a smidgen of sociology say it ain’t quite so.

Here’s why.

About 300 million Americans are old enough to be vaccinated. For the moment, let’s assume that 80% of us have been or intend to get vaccinated, and the other 20%, the villainous anti-vaxxers, continue to refuse (as the latest polls show). If 90% of us pro-vaxxers get immunized, then 72% of the eligible US population (80% x 90%) will be clinically safe, which by itself exceeds the 70% herd immunity threshold. But…

Anti-vaxxers, a majority of whom are Trumpian Republicans, tend to clump: to work, dine, shop, pray, party, and shoot together. Most of the rest are localized groups of minorities who tend to distrust government. They also clump. Let’s assume nonetheless that 20% of our anti-vaxxers are sane enough to sneak down to their local pharmacies in the dead of night and roll up their sleeves. Then 80% of their comrades will still be exposed, less those who’ve already been infected.

If 8 million clumpers are immune by infection today, then 40 million remain at risk (16% x 300 million – 8 million). That’s forty million. A significant portion are expected to refuse vaccination until they achieve group immunity the old-fashioned way: by infection. That will take time, which means that large “sub-herds” will continue to be vulnerable—and incubate variants—long after almost all of the rest of us have been immunized.

Herd immunity in general does not mean herd immunity everywhere. Be careful out there.