Wednesday, April 29, 2009

WHO Laboratory Confirmed A/H1N1 Cases

Well the World Health Organization just raised the Pandemic Alert Level to 5 from 4 (the raise to 4 was yesterday). Here is a graph of the laboratory confirmed cases of A/H1Na1, the flu previously known as "Swine."


Wisdom Speaker said...

Comments taken from CalculatedRisk threads...

Keep it up; you and I are on the same page with the flu thing. I had some comments for you last night, looks like you missed them:

Another good infection-spread map is here:

Apropos of your chart of the numbers, some of the ramping up is probably institutional "catch-up", but I think it's pretty clear that the number of real-world infections is growing fast enough to double in 4 days or less. The total number of real infections (not just the ones counted by WHO so far) has to be in the 10s of thousands. Given the exponential growth rate, I'm starting to wonder whether the pandemic could reach full bloom by the end of May or early June...

Comments from last night added below:

@energyecon and a few others: I see we're thinking alike. The mortality rate will continue to evolve with the virus. I wonder if it's possible that there's been a slight shift in the Mexican virus which doesn't show up on the lab checks, but which has dramatically boosted the lethality for a subset of the cases?

Looking at the rate of spreading / exponential growth - if we assume a single index case back in late February and a minimum of 10,000 cases in Mexico alone now, then that's at least 13 doubling periods in 60-70 days, or about 4 days per doubling. (I think 10,000 is way low, but one can adjust for whatever it takes to yield 2000 "officially counted" hospitalizations in a nation whose response has clearly been less than optimal. I am noting anecdotal evidence that ambulances and hospitals are refusing care now, which suggests a more dire scenario...)

A doubling time of 4 days gives a 2^10 increase in cases (factor of 1024) in 40 days... That would mean adding three zeros every 40 days or so... if that were to continue worldwide, we'll be done before the end of June... 10,000 cases now, 10,000,000 by end of May, and perhaps billions in June. Given that, I now worry that the 18 month scenario (e.g. from 1918-1919) may play out in less time, this time around, because people move much faster by airplane and auto than they used to by ship and train, and they interact more.

The other wildcard I see is that with early summer weather (in the Northern Hemisphere at least) perhaps the virus will find it tougher to survive. On the other hand, Mexico is further along with spring than nearly all the rest of the Northern Hemisphere (weighted by population), so this doesn't seem like a functional argument.

Wisdom Speaker said...

4/30: The World Heath Organization has confirmed 236 cases of swine flu infection worldwide, the agency said Thursday, a jump from 148 cases reported the previous day.

Again, there is some catch-up going on with the test results. It looks like these "official" test results take 24-72 hours to propagate to the WHO database.

Wisdom Speaker said...

From same article "WHO is troubled because in one case in Spain, the virus was transmitted from person-to-person within the community. [...] If Spain sees more such cases of community transmission, the world body may have to elevate its pandemic alert to its highest level, Phase 6."

Ron said...

H1N1 is truly a dangerous disease nowadays. It could kill alot of lives. To know if you acquire this, have a test using ELISA kit. It could detect many substances and diseases in our body.