7. Live Virus vs Dead Virus vaccines. – Dead virus vaccines in my research are well, useless. The whole purpose of a vaccine is to infect you with a tiny amount of virus. What your body does is fight the disease and creates an antibody specifically for the virus it fights. The dead virus is not what you get with a live virus. So when you get the same strain as a live virus you will get sick, because your body is only able to fight the dead strain.