"What have we found out about the influenza A (H1N1) 2009 pandemic virus?" - article in Journal of Biology (BMC open access)

Question and answer format.
Published online September 18, 2009. Questions include:

The 1918 pandemic influenza virus is said to have started by causing relatively mild disease in the summer but to have become more severe in the winter. Do we know why, and might influenza A (H1N1) 2009 do the same?

What about the possibility that influenza A (H1N1) might recombine with other more virulent viruses?

Might immunity built up in the course of the Northern hemisphere summer lessen the impact of the pandemic in the winter?

...etc.