The problem with current vaccine therapy is that it targets the pathogen after it has gained access to the body. Once in there, it meets the antibodies which effectively blocks the pathogen from further damage. But there are 1-2% who still get ill even after vacccination. It's like barricading the kitchen door leaving the robber to enter thru the front door. Once inside the armed home owner kills him with his shot gun. The next research is therapy that will focus on the mucosal lining, that is the front door entry point for the virus. A spray vaccine in the nose will be the most effective and we wont need any more shots. In my opinion, this therapy will have to be applied many times a year because the mucosal lining is often weakened by changing environment.