as of today (June 29th, 2009) the registered number of infections has risen to 71 578 in 106 countries with 320 fatalities. But, Anne Schuchat, MD, the head of CDC (Centers for Disease Control), has estimated that the real number of A/ H1N1 infections is MUCH higher, namely about 1 million in the US alone!!
In contrast, the officially registered cases in the US only amount to about 27 700 as of June 20th. Here is the link to the weekly CDC updates for the US:
http://www.cdc.gov/h1n1flu/update.htm
Today, 5 days after my last H1N1 plots, some qualitatively new features can be observed from the latest data on infections and fatalities. They are somewhat disquieting...
First, consider the meanwhile familiar semi-logarithmic plot, where we see clearly that the exponential growth law for the infections (blue dots) continues without change, with a doubling of cases about every 14 days. But as to the fatalities (red dots), a clear increase of the exponential slope has taken place since about day 45:
The blue line that I drew through the red fatality points after day 30 to guide the eye, now has the same exponential slope as the infections curve! Before day 45, the slope was considerably flatter for the fatalities (black line)!
In the following linear ratio plot of [tex]\frac{\rm fatalities}{\rm infections}[/tex] (now in percent) you see this recent dramatic change quite clearly. While until day 45 the ratio of fatalities decreased linearly with time (early visits to doctors,...), it now oszillates around and towards a constant fraction of fatalities of about 0.44 %
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Is this change of behaviour a first quantitative sign that the
virus has mutated and is becoming more agressive now??
Remember that since about day 45 it is winter in the southern hemisphere
and the seasonal flu has started there, interfering with the Swine flu...
If this somewhat steeper growth of fatalities persists, the prediction for the
number of fatalities by the Swine flu worldwide is at least:
- today: 320 (OK),
- in 3 months from now: 28 367,
- in 6 months from now: 2 516 220 worldwide (<=> 8.2 % of US population killed!)
Here is the best fit exponential formula (= blue line through red fatality data in my first plot above):
#fatalities = 161 * exp((t-47) / 20.4)
where t = 61 days <=> today June 29th 2009, and one month is
taken to have 30.5 days (on average).
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Last not least the same data in a linear plot as usual, where you can appreaciate the very strong growth...
Fridger
