Seems worse in Mexico?

It's speculated that one reason more people have died in Mexico as opposed to the United States is that the life span of the virus could have been longer in Mexico.

After flu infections, people can develop an additional bacterial "superinfection" that could be lethal, said Brian Currie, an infectious-diseases doctor and vice president and director of clinical research at Montefiore Medical Center in New York City. Currie said it remained a mystery why people in Mexico were dying while the cases reported in the United States have been relatively benign.