The first vaccine was the lymph from a cow ( vacca ) infected with a virus that when inoculated into humans protected them from smallpox. It was the first biologic
preparation for protection against a specific disease.
When bacterial protective agents were developed, they were called "vaccines" even though not produced in a cow.
Now the name is being given to agents not for protection from infection.


British biotech firm Xenova Group Plc said Tuesday its experimental vaccine for cocaine addiction had shown signs of reducing the euphoric effect associated with taking the drug, boosting its shares.

Seems a poor choice to me.

As usual, attempts to treat symptoms (not the cause) has created a consumer product and then profited from having the wrong word applied to its function.