What’s true of a population isn’t true of any individual person
in it. For example, a population has an average height. No
single person is exactly that height. To confuse the two is to
commit what is called the ecological fallacy. A more serious
example concerns a cornerstone of public health: vaccination
against the flu. The journal Science recently devoted an entire
issue to the controversy surrounding two studies that were held
up for publication because they described methods used to create
highly pathogenic strains of influenza virus for the purpose of
developing vaccines. Although the two studies were eventually
published, the articles in the special Science issue explore the
implications of such research. In one article titled “Influenza:
Options to Improve Pandemic Preparation,” the authors outline an
aggressive program of vaccination. They advocate increasing the
capacity to develop, manufacture, and deploy vaccines, including
what they refer to as “universal” vaccination—meaning
vaccination whether