A lot has happened in the last week.  I was frantically preparing for a big talk that I had to give at the end of the week when the news about swine flu started heating up.  As of the most recent posting from the Pan-American Health Organization, there are 1118 confirmed cases and 27 deaths in 18 countries worldwide. The United States has had 279 laboratory-confirmed cases and one death.  As I write, it sounds like the epidemiological situation is much better than it could have been.

But last Monday things were looking like they were going to get very serious. While I should have been preparing for my talk, I spent the day working out the details for an internet-based survey on people's knowledge, attitudes, and behavior regarding the emerging H1N1 (a.k.a. "swine") flu. Marcel Salathé and I realized that we had an historic opportunity to field a survey and learn something about people's responses as the public health emergency unfolded.  Our survey has been online since the morning of Wednesday, April 29th (and is available here for anyone interested in taking it -- it's only 16 questions long and takes less than five minutes to complete) and we have gotten well over 5,000 responses so far. Vijoy Abraham at the Institute for Research in the Social Sciences was amazingly helpful in helping us get the survey online in a hurry, and IRiSS very kindly hosted the survey.

Marcel posted a nice blog piece on the survey and it was later picked up by Carl Zimmer on his blog, and then the big-time: we got written about on boing boing.  This idea clearly resonates with people.  Stanford put out a press release and now Marcel and I have done a number of interviews for various local and international media outlets (links forthcoming).  All this before we've even done any analysis!

We will keep the survey online as long as it is relevant, though we will begin doing some exploratory data analysis shortly. The thing about flu is that, even though it seems like it is fizzling out already, it could actually kick around for months. I was speaking with a prominent disease ecologist this past week who predicted that this particular outbreak would fizzle in the northern hemisphere for the time-being. You see, by May, we are pretty well past flu season in the north.  For whatever reason, flu shows marked seasonality in transmission.  Jeff Shaman at Oregon State has shown pretty convincingly that this seasonality is a matter of absolute humidity, which is lowest in the winter in temperate regions and is presumably more conducive for influenza transmission and virus survival. The disease ecologist who made the prediction for northern-hemisphere fizzle also suggested that the southern hemisphere might be in for a hard flu season during the austral winter.  Extensive and sustained transmission could be bad news for those of us who feel like we've dodged a bullet here in the north because when flu season rolls back around here, we might get slammed on the rebound.  A very interesting paper by Cécile Viboud and colleagues shows that it was the second influenza season that had the higher mortality rates during the last influenza pandemic of 1968.  The moderator on ProMED-mail wrote "Even if the present A/H1N1 has pandemic potential it is therefore highly likely that the outbreak will fade out within the next 2 to 3 weeks, but it will reappear in the autumn."  Time to get cracking on getting this H1N1 strain incorporated into the next flu vaccine, I'd say.

This means that we will probably need to keep our survey up for a while to come.  It will be interesting -- and hopefully informative -- to see how people's anxieties and knowledge about swine flu wax and wane as this system evolves. 

That's all for now though I suspect this won't be the last post I write about swine flu. Oh, and the talk turned out fine; thanks for asking...