>>13797916>If it's not too much effort then please do, though.Sure. I'm defining herd immunity as an effective reproductive number (Re) below 1. That means that without any change, the virus will burn itself out on its own. Re is a function of basic reproductive number (R0; the infectiousness of the virus), and the proportion of people susceptible to infection (S).
Re = R0 * S
where S is further defined as a function of the proportion of the population that is vaccinated (X), and vaccine efficiency (Ve) such that:
S = 1-X*Ve
For the alpha variant, R0 = 3 and Ve is 0.95. So all we need to do is solve for X:
R0 * (1-X*Ve) < 1, which gives ~0.73. So in other words, under the alpha variant, with roughly 70 percent vaccinated, the virus cannot spread exponentially anymore and infection rates die out.
For the delta variant, however, the basic reproductive number is higher and vaccine efficiency is lower: (R0 = ~8 and Ve ~0.8). Solving for X again gives us ~0.9. So you'd need to be at roughly 90% fully vaccinated, and assume Ve remains at ~0.8 for long enough to kick in. That is a game changer relative to alpha, and it seems unlikely we're going to get there with vaccinations alone.
>BelgiumMaybe the number you mentioned refers to the percentage of the *adult* population. It's often reported that way in the media. But what matters is the proportion of the total population, since the virus doesn't care how old you are.
>My concern isn't with the course the numbers were taking but rather with our government's wilful ignorance/hubris around the issue. If it was too late but they maintainted their promise then I think I have the right to feel angry.Sure, I understand that. From following the way it's been going in Belgium, they messed up on many fronts, not just communication with the public.
