Jul 4, 2009

H1N1 Swine Flu Projection

Strange... a lot of (WHO) swine flu talk and information on the Internet, but no worldwide projections or estimates....

The risk of underestimating the so called H1N1 (Swine Flu) virus is not unthinkable.

Worldwide Projection H1N1 Virus

You don't have to be an actuary or mathematician to make a sound projection of the number of people that will be infected (or die) within the next months. All it takes is 'basic high school' and a common spreadsheet.

Let's make a simple worldwide projection of the expected cases (infections) based upon the WolframAlpha data-set:



The purple line illustrates the development of the number of infections worldwide, the dotted purple line illustrates the expected projected development until the end of july 2009.

With one view it's clear is that during the next months the H1N1 virus spread will be enormous. By the end of July 2009 the number of worldwide infections will rise to almost 0.5 million. The spread of the virus will probably be enforced by the fact that a lot of people have their holidays and therefore travel by plane or bus.

As one would aspect, the development of the number of infections is exponential. The (natural) logarithm of the expected cases (dashed red line) is almost a linear curve. You may find more information of data and projections in the next XLS spreadsheet.

Big Explosion
If no additional prevention actions will be taken, a big explosion of the virus starts just after the holiday period in 2009.



It is questionable if the planned vaccinations for October or later will be in time.Perhaps it's better to have a vaccination, or take Tamiflu, than a vacation in July or August.

Global Infection
If no adequate rigid measures will be taken within the next months, the future of humanity could be serious at stake:



Unrestrained exponential growth on basis of the the current growth-path, will lead to a more or less complete global infection by the end of January 2010.

By then ruffly 36 million people worldwide, will have died. If the mortality rate doesn't stabilize (as it currently appears) at 0.45% of the infected people, the effects could be worse.

As the famous 'Wheat and chessboard problem' already illustrated, exponential growth is a dangerous underestimated killer. It's just like a tsunami: when you notice it, it's too late to act.

Let's trust governments are not underestimating this Swine virus threat.

Happy holidays!

Related Links:
- World Population Density
- U.S. Death rates influenza virus 1918
- Visual Flu Tracker
- LinkedIn: InArm: Important remarks by Dave Ingram

Important Notice

4 comments:

  1. See this NY Times article for an assessment of two widely promoted studies that forecast a very mild growth in cases back in May,
    Models Miss the Mark.

    I trust your spreadsheet more than the epidemiologists' supercomputers. Especially given that they had to tinker with their models to accommodate "unexpected infusions of cases" they blame on school children. Actually, in all models of real processes you must expect the unexpected.

    I traveled to Texas in early May during the outset of the pandemic, and did my own exponential growth rate calculations on the back of a napkin to evaluate what my risk of exposure was looking forward one week. Would infections grow to such an extent that I may not be able to travel?

    Despite the media hype -- my chances of winning the Lottery were the same as my chances of crossing paths with somebody in Texas who had the swine flu, and then it possibly being transmitted.

    Amazingly, the risk of being exposed to swine flu today is greater, yet the media are all hyped-out about it (I guess).

    Influenza normally exhibits a seasonality, so the onset of heat and humidity is a factor many see as curtailing the flu season during the summer months. Many pandemics have historically occured in waves, and so this is likely just the first herald wave in that regard, therefore a strict exponential growth rate wouldn't apply over the long term.

    However, the number of cases have not yet been observed to fall, perhaps due to the mild El Nina summer in the Americas.

    One other note, Tamiflu is not a vaccine. It is one effective drug treatment (with the note made by the article you linked to), another option is named Relexa. The volunteer studies of vaccines to be ready this fall are just beginning.

    ReplyDelete
  2. Thanks for your positive reply.

    1. I fully agree on the 'seasonality', however.... As there are no signs in May and June that the constant exponential growth shows a beginning of decline, one must be prepared for the worst, take no risk whatever and immediately take actions, before it's too late.

    2. Indeed, I agree,strict exponential growth rate doesn't apply on the long term. It only shows what could happen if no adequate measures will be taken.
    I would 'guess' a 90% probability on the 0.5 million infected in August, a 80% probability on the
    61 million in November and a 50% probability on the 1.5 billion at the start of 2010. However.....

    3. Indeed, Tamflu is not a vaccine. I'll correct the suggestion in the blog. Thanks again.

    ReplyDelete
  3. Swine Flu is indeed a terrible disease that the whole world is alarmed. We can know if we acquire this kind of disease if we try to have a test using ELISA kit. This will really help us.

    ReplyDelete
  4. At this time I am ready to do my breakfast, later than having my breakfast coming over again to read other news.


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    ReplyDelete