A couple of weeks ago I was interviewed by a journalist from Deutsche Welle – a German broadcaster and news agency with an international reach. The result is an article linked here.
The key points: Maths for herd immunity is deceptively simple, but there is a lot of complexity that it tries to capture.
Politicians often need a goal that can be reached and the 
formula can provide this, but the uncertainties associated with what 
value should be used and how vaccination affects the immunity render the actual value basically useless.
This would not have been a problem, was it not for the natural optimism of politicians and societies, often to the point of reckless disregard of the warnings by epidemiologists, modellers and public health scientists. Just to stress this:
There is no “magic” vaccination level that once reached it will make us all free – see the newest outbreaks in Israel.
We need to keep vaccinating, to keep borders closed, to protect children at school, to support those who need to self-isolate.
We need to support those who cannot afford vaccines or cannot afford to protect themselves, even globally.
We need to recognise that vaccine protection is something that can be gained, but also can be lost.
We are not fully safe, until we are all safe.
