Published online 5 May 2009 | Nature | doi:10.1038/459014a


How severe will the flu outbreak be?

Epidemiologists race to pin numbers on the global H1N1 spread.

The World Health Organization (WHO) this week remained on the verge of declaring a pandemic of the H1N1 swine-associated flu virus. Public-health bodies and scientists have made progress in starting to understand the outbreak, but major questions remain about how severe the disease will get.


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  • This is very helpful. Does anyone know what the generation times of other infectious diseases are?

    • 06 May, 2009
    • Posted by: Sean Stromberg
  • If indeed the virus spreading around the world now is a mild version, wouldn't it be better to be infected now, suffer the minor version, and thus acquire immunity against the more severe version which may well arrive in the winter flu season, than to stay clear now and take sick later? (Assuming vaccine will only be available for a limited number of people.)

    • 06 May, 2009
    • Posted by: William Brookfield
  • If you assume that a more severe version will appear in the future, that is a logical approach. However, as I think the article makes clear we neither know if this is a particularly mild strain nor if a more virulent strain will appear in the future. Consequently, the only certain outcome of infecting people with this current strain is that some of them will die.

    • 06 May, 2009
    • Posted by: Tim Vickers
  • If pandemic would be defined in terms of how widespread the flu is geographically and not the number of human deaths, then H1N1 flu could be taken as near pandemic. The flu may appear to be receding, but it could be only the first wave ? there must not be any complacency yet. If a second wave were to move in, it would be many times worse. WHO is right to be alarmed and keeps issuing grave warnings ? never mind even seen by some to be over-reacting. Everyone on guard? YES. Panic? NO. Just be prepared for any adverse eventuality. (Tan Boon Tee)

    • 06 May, 2009
    • Posted by: B T Tan
  • could you fix the photo link so it expands the pic?

    • 07 May, 2009
    • Posted by: Diana Podein
  • Even in Mexico City, the risk from swine flu is marginal - you're more likely to die in a freak accident, or from ordinary seasonal flu, than from swine flu. I'm no virologist, but surely while this particular strain could mutate into a more dangerous one, the same is true of other strains? I don't think the response to swine flu can be characterised as anything other than outright hysteria, especially by certain governments. China effectively kidnapped healthy Mexican nationals, solely on the basis of their passport, some of whom that had not been to Mexico in months or years; Argentina suspended flights to Mexico, highly ironic given its own dengue fever epidemic; France wanted to cancel all flights between Mexico and the European Union, though not flights to sub-Saharan Africa (the relative numbers of swine flu patients in Mexico and of AIDS patients in sub-Saharan Africa needs no further elaboration, and swine flu is essentially curable). We might as well ban cars due to people killed in traffic accidents. Ordinary Mexicans foot the bill for this pandemic of hysteria, with its ruinous costs far outdoing the damage done by the disease itself.

    • 09 May, 2009
    • Posted by: Rodrigo Sanchez