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[QUOTE=Starlight;742193]It's statements like this that confuse people. If you assert that the curve is (solely) determined by the virus, you're implying it's not determined by other things, e.g. government policy around social distancing. [/quote sti]
Your still not reading my posts completely, and yes the world is panicing and confused beyond belief. I said, "the pattern of the curve is determined by the virus."
The coronavirus has a distinctive curve
No chance involved here. There is no such thing as a 'lovely symmetric curve. Still very awkward disjoint communication on your part.
Your still not reading my posts completely, and yes the world is panicing and confused beyond belief. I said, "the pattern of the curve is determined by the virus."
Perhaps what you mean is something more along the lines of "this virus seems to have a distinctive bell-shaped curve, whose height can be changed through different government policies (e.g. around social distancing)".
I think your symmetry assumption is fundamentally wrong though.
Initially in most countries, in the absence of social distancing measures, etc, the virus will have had a certain R0, so those countries will see an exponential curve rising at that rate. After there is a serious policy intervention - lockdown / social-distancing etc, there is essentially a new R0' relating to the virus spread (e.g. in NZ this was <0.5), and so you get a new exponential curve beginning around then whose growth or decay relate relates to this new R0'. Your assumption that the resultant graph will be symmetrical, assumes that the new R0' will happen to be the inverse of the original R0. There is no particular likelihood of this being true. The new R0' will be almost totally dependent on the rules implemented and level of compliance with them, so could range from almost zero to as high as the original R0. So only by chance would the two phases of the curve be symmetrical with each other.
Typical R0 values seem to be 1-5 (most often 2-3) for the initial outbreak, and then around 0.3-2.0 for the post-intervention R0'. If the initial R0 happens to be 2.0 and the R0' happens to be 0.5, you'll get a lovely symmetric bell curve since those are inverses. But if not, not. So there can be symmetry by chance, but it's not particularly likely.
Initially in most countries, in the absence of social distancing measures, etc, the virus will have had a certain R0, so those countries will see an exponential curve rising at that rate. After there is a serious policy intervention - lockdown / social-distancing etc, there is essentially a new R0' relating to the virus spread (e.g. in NZ this was <0.5), and so you get a new exponential curve beginning around then whose growth or decay relate relates to this new R0'. Your assumption that the resultant graph will be symmetrical, assumes that the new R0' will happen to be the inverse of the original R0. There is no particular likelihood of this being true. The new R0' will be almost totally dependent on the rules implemented and level of compliance with them, so could range from almost zero to as high as the original R0. So only by chance would the two phases of the curve be symmetrical with each other.
Typical R0 values seem to be 1-5 (most often 2-3) for the initial outbreak, and then around 0.3-2.0 for the post-intervention R0'. If the initial R0 happens to be 2.0 and the R0' happens to be 0.5, you'll get a lovely symmetric bell curve since those are inverses. But if not, not. So there can be symmetry by chance, but it's not particularly likely.
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