Thank the Lawyers: The forces behind the flu vaccine shortage:

Vaccines are the one area of medicine where trial lawyers are almost completely responsible for the problem. No one can plausibly point a finger at insurance companies, drug companies, or doctors. Lawyers have won the vaccine game so completely that nobody wants to play.

...So why is it that 100 percent of our flu vaccines are now made by two companies in Europe? The answer is simple. Trial lawyers drove the American manufacturers out of the business.

As they say, read the whole thing.