Delta variant renders herd immunity from Covid ‘mythical’
theguardian.com
theguardian.com
Hopefully someone invents an Immune-System-As-A-Service we can all subscribe to!
With estimates of 60% vaccinated for herd immunity all the way up to 85%, seems like nothing but guesses.
https://www.medpagetoday.com/opinion/vinay-prasad/90445
It would have looked a lot more professional to either say "We don't know" or say that as many as possible should be vaccinated.
The only people that have done a good job are all the people involved in creating the vaccines.
If an infected individual would spread the virus to an average of 2.5 other people without vaccines, but less than 40% of these spread the virus further because more than 60% are vaccinated, R < 2.5 × 40% = 1 means exponential decay.
If, on the other hand, an infected individual would spread the virus to an average of 6.6 other people, but less than 15% of these spread the virus further because more than 85% are vaccinated, R < 6.6 × 15% = .99 means exponential decay.
So the estimated herd immunity threshold depends on how the virus spreads on average, which in turn needs to be estimated from actually observed spread, so the estimates need to be changed as more observations are being made.
> Reading about herd immunity and the now established fact that it is unobtainable
This fact would need to be established the same way. If vaccinating 100% of the population only stops the virus 49% of the time and assuming again that an average individual would spread the virus to 6.6 others, R = 6.6 × 51% > 3.3 means exponential growth.
However, the 49% in the article are only about preventing infection, not preventing spread, so it's still possible that R < 1 in a fully vaccinated population, at least given the information presented in the article.