Why is this years flu epidemic so bad when almost half the country has been vaccinated? Cdc estimates 128-162 million doses administered.

Just the way it is. Prior doctors answering was incorrect..The flu vaccine is 60% effective. But just because you get it doesn't mean you won't get the flu. Also..The vaccine for the current year is constructed from last years strain. Strains change (antigenic shift and drift..Plus outright mutations).
Flu shots don't work. This is more evidence that the flu vaccine is largely ineffective. This is the belief of many esteemed scientists who have analyzed the data from multiple studies. I believe that taking vitamin d and n-acetyl cysteine is a more effective way to reduce chances of getting the flu! see http://well.Blogs.Nytimes.Com/2012/11/05/reassessing-flu-shots-as-the-season-draws-near/?Smid=fb-share and comment:.
Natural disasters? The country's infrastructure for giving flu shots to those at highest risk was disrupted by natural disasters (hurricane sandy in the eastern shoreboard, droughts in the midwest). I believe this led to those at highest risk (the poor, those with chronic diseases, or those most affected by the natural disasters) not being able to get the shot. Just a guess though!