Something that I think is worth explaining: The term "herd immunity" has a few different meanings, all of which are quite precise. This is an important pointpic.twitter.com/PBnK4J6ntD
You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more
The #GreatBarringtonDeclaration, for example, uses the first definition in a very disingenuous way to imply that endemic transmission of the disease (where Rt may at some points be <1) is equivalent to population immunity that prevents outbreaks
If someone uses the term "herd immunity" to describe an actual strategy or outcome from COVID-19, it's worth digging in to EXACTLY what they mean by that term, because often it's very much not what you'd imagine
And if you're interested in reading more, this article is a great place to start:https://academic.oup.com/cid/article/52/7/911/299077 …
Also, I made an error in the second tweet - in a strict mathematical sense, herd immunity is having sufficient people IMMUNE to the disease in a population. Infection does not always confer immunity, and you can be immune without infection (vaccines!)
However, it isn't really permanent. Because of people entering and leaving the population (births, deaths, migration) R0 can fluctuate above and below the level needed for herd immunity for a particular virus. Also, immunity (acquired or vaccine) may be temporary.
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.