SvennoJ said:
That sounds more plausible atm. It's hard to tell since it depends so much on population density and general behavior of people. It will also accelerate when more people are contagious within the same building. More virus particles circulating around in a closed environment.
Very crude unscientific assesment
Late August start, we're about 300 days in, reaching 7.2 million reported infections world wide, representing perhaps 70 to 100 million actual infections. To reach 100 million today from a patient zero 300 days ago, 1.063x increase per day, global R of 1.37 with lock downs.
China had 1287 reported cases on Janurari 24 (lock down) yet likely at least 20x as many with spotty early testing.
150 days from late August to Jan 24th.
25K cases (20x more than detected) would be 1.070x daily increase, R of 1.41
50K cases (40x more than detected) would be 1.075x daily increase, R of 1.44
130K cases (100x more than detected) would be 1.081x daily increase, R of 1.5
Changing the start to late September (120 days)
25K cases (20x more than detected) would be 1.088x daily increase, R of 1.54
50K cases (40x more than detected) would be 1.094x daily increase, R of 1.58
130K cases (100x more than detected) would be 1.103x daily increase, R of 1.65
Changing the start to late October (90 days)
25K cases (20x more than detected) would be 1.119x daily increase, R of 1.78
50K cases (40x more than detected) would be 1.128x daily increase, R of 1.85
130K cases (100x more than detected) would be 1.140x daily increase, R of 1.95
It all depends on how many cases were missed and when the infection actually started.
The first confirmed cases was traced back to November 17th, but that was not patient zero.
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Calibrated molecular clocks and genetic analysis indicate all SARS-CoV-2 viral strains descend from the basal types found in Wuhan at the beginning of the year, though, with the earliest possible spread sometime in December (and the virus jumping from animal to human hosts between October and December). Besides, we have data from register offices, adjusted to the day of death, strongly suggesting very rapid spread in the preceding weeks. Bergamo lost 0.4% of its population in a few weeks in March, for instance, with dramatic peaks of abnormal mortality also happening in New York City and Spain soon after.
I think we can confidently argue spread began before everyone was paying attention in a lot of places, but the exceptions like Taiwan and New Zealand would also mean the virus spreading that early wouldn't really make sense in the context of their success. For some reason, the reproduction rate seems just that different from place to place, so there isn't much we can make of it. Why the attack hate was 60% in Bergamo but 10% in Wuhan, for instance?
