Reply #36: A few points:

[Spider Jerusalem]

first, the infection rate in the US is significantly lower, at present. It is therefore not possible, on the basis of a smaller set of subjects, to draw useful conclusions, because the depth of data is just not there yet. (Over a thousand known cases in Mexico, less than a tenth as many thus far in the US.)

Reports of US cases of the virus are of a relatively mild illness; the differential factors are unknown, but can be guessed at (overall health, nutrition, environmental factors like air pollution, and possibly even altitude...Mexico City is at 7300 feet above sea level). But it's also not known yet whether there is more than one subtype of this previously unknown flu strain; it's certainly possible (and viruses that are previously unknown in human populations can become much more deadly after mutation; the 1918 flu struck in three waves...the first had relatively low mortality, but the second and third did not).