Am I to assume it wasn't as brutal in the SH because they have had more exposure the strain?
No, it was quite severe in Australia and New Zealand (although I'm not sure about children's deaths). I think that Fujian just emerged in China at the end of 2002.
Last year Fujian emerged from Fujian Province in China. The virus was detected in several locations in mainland China and also made an appearance in the US in early 2003.
In the spring the components of the current vaccine were chosen. Fujian was on the radar screen, but the initial isolate, A/Fujian/411/2002, did not grow well in eggs, which is how flu virus in killed vaccines is produced. A/Wyoming/3/2003 had just been isolated and there was little data on its stability in eggs. Therefore, the current vaccine used the tried and true A/Panama/2007/99 to represent H3N2 strains.
This summer Fujian was the dominant strain in Australia and New Zealand. It was one of their worst flu seasons and a Fujian-like virus was selected to replace Panama-like for the upcoming flu season in the southern hemisphere.
Thus, the vaccine under development will be ready for the flu season in the southern hemisphere, but it will be too late for the current season on the northern hemisphere.