What's the difference between receiving a vaccination (a type of active, artificial immunity),and serum (a type of passive, artificial immunity)? A serum comes from someone who has already had a specific disease and has developed antibodies against it. It does not last as long as a vaccination, because it does not provoke the body to create its own immune response. A serum is created by the body's own cells in response to infection; vaccinations use artificially created antibodies. The body can live without vaccinations, but not without antibiotic serums. Serums come to us via the placenta while in the womb, while vaccinations come immediately after birth..