Herd immunity against Covid-19 is unlikely. But we aren’t powerless

No small achievement: Despite the failure to prevent all infections, vaccination has dramatically reduced the number of Covid-19 deaths in most countries. – AFP

“A MAN has got to know his limitations.” That is one of the memorable phrases uttered by “Dirty Harry” Callahan, the fictional police inspector played by Clint Eastwood.

Today, the world is learning its limitations in the ongoing Covid-19 pandemic, and the most important lesson is that a key strategy we banked on to defeat the virus – herd immunity – appears unobtainable.