Not sure what you are talking about... I was exposed to rabies 3ish years ago and received the PEP (post-exposure prophylaxis). The most painful shot was the rabies immunoglobulin, merely because it was a fairly large volume, maybe a couple cc's IIRC. That shot is only needed after exposure and is not a vaccine. The vaccine came as several shots spaced apart by days/weeks, and each individual shot was smaller and less painful than the seasonal flu vaccine. In fact, I literally did not feel the nurse give me one of them.