Swine flu graph update — A(H1N1) hits phase 6 and “moderate” severity

I wrote about A(H1N1) (alias “swine flu”) last week.

A reader requested an updated graph, so I’ve provided that below. Significantly, today WHO declared that A(H1N1) entered phase 6 and was “moderately” severe. Since the new phase system WHO has developed really doesn’t consider severity and only looks at how far widespread an influenza outbreak is, phase 6 (and all of the phases) are, in my uneducated and biased opinion, relatively meaningless.

The graph shows that the merely-linear increase in cases is still in place. No signs (yet) of exponential growth.

[graph showing A(H1N1) swine flu cases through 2009-Jun-11

4 Responses to “Swine flu graph update — A(H1N1) hits phase 6 and “moderate” severity”

  1. Matthew Jones Says:

    A graph of daily new reported cases can be expected to be very noisy.
    If the total cases grows exponentially, then yes, its rate of increase and all further derivatives will be exponential. But even if the disease spread were perfectly exponential, and all noise due to measurement/sampling difficulties (eg cases unreported, or confirmed cases delayed declared in clusters) then the daily new cases would be expected to be noisy due to small number of cases (per day).

    To see how surprisingly good the fit to exponential growth has been over the last month or so, see the wiki page:
    http://en.wikipedia.org/wiki/File:Influenza-2009-cases-logarithmic.png

    As of now (July 26), all major graphs have been closely exponential since May 14th or so. (thus appearing as straight lines on a semi-log plot)

  2. Stephen Says:

    Very interesting, Matthew. I’ll be updating my chart shortly. I did see the news item that we’d crossed 1 million official cases today.

    I have a version that goes by week, too. The data previously (not updated) was:

    4/29: 148
    5/7: 2,223
    5/14: 4,126
    5/21: 4,537
    5/28: 4,476
    6/3: 3,763
    6/11: 9,501

    Certainly a very long period with flat growth, punctuated by a double at the end. Will be interesting to see if it did double again for both 6/18 and 6/25.

  3. obeidah Says:

    i want to use this graph (of course including proper citation) for a research project i’m doing. to what extent is this data reliable? how did you collect this data?

  4. Stephen Says:

    Feel free to use it — the source was WHO itself. I collected it by downloading the data from their site and graphing it.

Leave a Reply

AVATAR: Sign up for a free avatar with Gravatar.
CLICK FOR COMMENT XHTML TAG HELP