https://www.washingtonpost.com/politics/2021/12/04/big-counties-are-proving-how-vaccination-works/

Much has been made of the gap between more-vaccinated and less-vaccinated states or red counties and blue counties. The difference is even starker in big counties with overwhelming adoption of the vaccines.

About 1 in 420 Americans has died of covid-19, according to official data. And we’re still averaging more than 1,000 deaths per day.

But in certain areas — and indeed in many areas in which the population is much more tightly packed and the coronavirus could transmit more easily — the story is far less grim. A big reason: widespread vaccination. Death rates are far below the national average in the most-vaccinated, often-urban areas.

Much has been written about the yawning gap in outcomes between less-vaccinated and more-vaccinated areas, especially as deaths in less-vaccinated, red states significantly and increasingly outpace more-vaccinated, blue states. The Washington Post’s Philip Bump also reported this week that deaths in red counties are more than 50 percent higher than in blue counties.

But even that might undersell just how beneficial vaccination is in preventing the worst that the coronavirus has to offer — particularly when adopted on a grand scale in a given area.

From the start of the vaccination effort, a pertinent question has been when we might achieve something amounting to “herd immunity,” i.e. having enough people vaccinated to stomp out the virus. Guesstimates often pegged that number at 70 percent or above. That concept has proven elusive, particularly as the delta variant has rendered the vaccines less effective at preventing the spread — while still extremely effective at preventing hospitalizations and deaths.