這是世衛的警告。青壯者倒是易受感染及致死。兒童及老人反而相對安全。

The majority of these cases have occurred in otherwise healthy young adults. Influenza normally affects the very young and the very old, but these age groups have not been heavily affected in Mexico.

Because there are human cases associated with an animal influenza virus, and because of the geographical spread of multiple community outbreaks, plus the somewhat unusual age groups affected, these events are of high concern.

http://www.who.int/csr/don/2009_04_24/en/print.html