How effective is a single vaccine dose against Covid-19?

[LONDONER]

Now that vaccinations are being given, this long article is pertinent since the British Government, against the advice of the vaccine manufacturers and the WHO, have decied to "stretch" the availability of  the vaccines by delaying the second dose to twelve weeks instead of three.

https://www.bbc.com/future/article/20210...obal-en-GB

[InbetweenDreams]

I think they have the similar sentiment here as well...