Most vaccines operate under this principle. They are a version of a virus that is crippled. Usually the DNA or RNA that is typically at the center of the viral particle has been removed. Without this genetic information the virus is just a shell of lipid and protein. But since the outer coating of the vaccine is identical to the virus, the immune system can be trained to detect the real one with the fake. It's like having identical twins; 1 is crippled and in a wheel chair. The cripple can't do much, but you can identify the healthy twin from crippled one.