A vaccine for headaches?

Much attention has been given in the media to the push for vaccines for malaria and HIV. However much more of the world's population suffer from man's old foe, the headache. If we had a simple injection into the head as children, we would never have to suffer again. Why aren't scientists working on this? Are they afraid that once they give us the vaccine, we will stop buying aspirin and their employers, the big drug companies, will go bust?