Rabies vaccine overdoses need to depend on how many extra shots were given. If the rabies vaccine was administered using the five-dose method, only one extra shot, or two extra shots, will not be harmful. However, if more rabies shots are given, meaning a dozen or even dozens of rabies shots in a year, the rabies vaccine cannot be more effective at that point. This is because the five-dose method of rabies vaccination allows a person’s rabies-neutralizing antibodies to rise to a relatively high value and to be maintained for several years. If another rabies vaccination is given, it will not allow the concentration of antibodies to continue to rise significantly, and the rabies virus and antibodies will not last significantly longer. It is just possible to have an adverse reaction to the rabies vaccine with more shots, and the likelihood of a person having an adverse reaction will rise with more shots.