Meanwhile Sweden is catching Norway in the number of reported cases (despite Norway having had a huge lead), and is already at almost 5x deaths (which, given the lack of testing, probably better reflects the true state of infection there).
kwlf wrote:
There is an article in the Guardian about the Oxford paper – there is also a link to it. It’s not an analysis to show how many people have been exposed. It’s an simulation to show how models of the disease outbreak can produce similar outputs in terms of mortality curves (reflecting reality) even if you start the models with a range of very different parameters.
If you have a clue of free transmission rate number (which you can fit on partial data if testing dynamics are the same) and the date of the first case, then here you go, no need for anything else 
- If a 1:2 virus was circulating freely then 50% will have it in 6 months
- If a 1:4 virus was circulating freely then 50% will have it in 2 months
I don’t think this style of modelling is rocket science, the hard bit is to empirically substantiate such claim with wide testing…
If a 1:4 virus was circulating freely then 50% will have it in 2 months
Isn’t that definition rather circular i.e. to achieve 1:4 you need a lot of mixing of the population.
So a given virus may achieve 1:4 in say London, Frankfurt, Paris, but will achieve a much lower ratio in a rural area.
Apparently this situation is happening all over Europe – except the UK where it is not mandatory to have a dog to go for a walk
We are allowed 1 walk per day, with a £30 fine which doubles on each consecutive offence, up to a maximum of £960. The result is predictable:
Yes, I was referring to whole population average but you can have tailored guess on each city/place, you are not much far from 1:4 in London vs 1:2 in SE rural vs 1:0 in Mull Head, but infected population averages will be in 1:4 region unless all Londoners go to Scotland 
The impact of confinement on that is even hard to guess, I am in Paris now, we just heard in the news only 20% of the mob is now confined in Paris, the rest went for countryside or overseas confinement given that people tracking is illegal (COVID19 tracking bill is still debated), the estimate was given by network operators on how many phones are still around
Maths looks nice but the data looks weak they could have cross-validated that model and the quality of data fitting and prediction on South-Korea?
I think 1%-5% of population would have worked well (still eye opener vs reported cases) but it does not sell as 50% in the press headlines
You barely need 100 test kits and 100 random persons to check that “50% hypothesis”, no point trying to test the whole population or runing fancy maths to accept/reject that statement, it is like claiming everybody in the UK is male, you don’t need to undress (or ask) that many…
at that time Boris Johnson & Cummings & Co were talking about doing nothing and herd immunity then completely change course…
Were they talking about doing nothing? I must have missed that. Do you have a reliable reference?
The impression I have is that they said they would (a) protect the old/vulnerable as far as possible while (b) allowing others to catch and pass on the disease in a more or less controlled manner so as to avoid swamping the healthcare service. I also got the impression, at every stage, that control measures would be adjusted as and when required.
Whether they’ve judged guessed it correctly, and whether people who recover do have immunity for more than a few days or weeks… that remains to be seen. If not, the UK may be in for a rough ride, like Switzerland, France and the Netherlands.
hmng wrote:
Now Medicine, like engineering, also uses nature’s laws and scientific discoveries and apply them to people’s health. But it is not engineering. And the proof is that, if it was, it would become cheaper and cheaper as time goes by :-)
You mean like aircraft?
Ibra, I think the epidemiologists take it to a high art. But unless you know what numbers to plug into your models they won’t work well.
FWIW an illness with an R0 of 2 will take an infinite amount of time to infect 50% of the population. An illness with an R0 of 4 will take an infinite amount of time to infect 75% of the population but a finite time to infect 50% of the population. An illness with an R0 of 4 will therefore infect 50% of the population infinitely faster than a disease with an R0 of 2, rather than just twice as fast.
Perhaps you meant something different by transmission rate number, such as the number of cases per unit time. But this will never be a constant as it depends on the infectivity of the microbe and the proportion of people who are already immune. As more people become immune, it will take longer for an infected person to find someone who is susceptible and the transmission rate will drop. This will happen faster for an agent with R0=2 than for an agent with R0=4. It will all be non-linear.
Peter yes, R0 is population-dependent.
One critique of the “Oxford study” is here.
They’ve received the maximal telling off that a Brit could dole out, quite strongly worded: “It’s a little concerning that they’ve taken it straight to the media,”
