Influenza Recap

Fear, anger and fatalism over swine flu in Mexico:

"But it may be too late to contain the outbreak, given how widespread the known cases are. If the confirmed deaths are the first signs of a pandemic, then cases are probably incubating around the world by now, said Dr. Michael Osterholm, a pandemic flu expert at the University of Minnesota.

No vaccine specifically protects against swine flu, and it is unclear how much protection current human flu vaccines might offer.

In Mexico City's Zona Rosa neighborhood, teenagers with spiky hair and tight jeans laughed at the danger.
'People are giving too much importance to something that isn't that big of a deal,' said Oscar Zarate, 19, shouting over the loud music and the jostling crowd outside a packed night club."

It will be interesting to see how this develops.

About a year and a half ago I was involved in developing a web application for visualizing results of pandemic simulations. It was intended as a disaster-preparedness application for governments and large (esp. multinational) corporations. The effects of all of the mitigations discussed in the article -- travel restriction, vaccinations, antiviral therapies, etc. -- could be compared in the web app.

Mitigation

I'm a little skeptical of the effectiveness of surgical masks, which seem to be a big feature of the initial response. Are masks really effective at keeping small viruses out of suspension in the atmosphere? The CDC says only that:

"Very little is known about the benefits of wearing facemasks and respirators to help control the spread of pandemic flu."

Recent experiments with guinea pigs showed that coughing and sneezing were not necessary for transmission of flu virus. Instead, atmospheric temperature and humidity determined how well the virus could be suspended in air, which is where it ended up as a result of normal exhalations by the test animals.

Those experiments, incidentally, were inspired by a report of events in southwestern New Mexico:

In an article published in 1919 that details the progression of the 1918 influenza epidemic at Camp Cody, New Mexico, the authors describe a parallel outbreak of pneumonial disease among their laboratory guinea pigs.

"The Great Influenza" gave a good account of the mitigations attempted in 1918 -- including use of surgical masks -- and of their effectiveness. The only thing which really worked then was quarantine. For example, Gunnison County Colorado escaped the 1918 flu with only two deaths, thanks to its stringent quarantine efforts. Silverton lost 10% of its population.


Early Detection

One question which our web application failed to answer was: how do you know when an outbreak is underway, i.e. how do you know when to start mitigation?

It's interesting that Google Flu Trends seems not to have picked up on this outbreak. Granted GFT monitors trends in the United States alone; but the CDC is already aware of cases in California and Texas.

Further Reading -- er, Viewing

PBS has produced some good documentaries on the 1918 flu.

"American Experience: Influenza 1918" (website) focuses on what it was like to live through the pandemic.

Although it's somewhat dated (IIRC it precedes successful recreation of the 1918 virus), "Secrets of the Dead: Killer Flu" (website) is a fascinating detective story about efforts to find the origins, and the keys to the effectiveness, of the 1918 flu.