[quote NannyAndJohn]@Whatever9999 You forgot to factor in the Indian Variant, with increased transmissibility over Old Covid of approximately 1.6 x 1.6 = 2.56.
Using this and your optimistic figure of 50% gives
Old Covid R0 = 3,
Indian Variant + vaccines R0 = 3 x 2.56 x 0.5 = 3.975.
You still think we can carry on without reintroducing restrictions?[/quote]
Sorry but just need to correct your maths, its been bugging me last few days.
If the alpha varient is 60% more transmissible than the original and the delta is 40% more transmissible than alpha (as stated by Hannock) then the maths comes out as
The delta varient being 84% more transmissible than the original varient, not 320% as you have it.
(1.4×0.6=0.84) which means that if the original r rate was 3, the new r rate would be 5.52, then with a 50% reduction it would be 2.76
Still not 1 I'll admit, but lower than your calculations and there are still other factors to consider, including the fact that the vast majority with symptom are isolating along with their families meaning that they won't be passing it on to as.many people.