A video created by a marketing agency or company that attempts to be a viral video
but is really nothing more than a commercial. A vaccine video often represents an attempt by an old school
company to "connect" to a "younger audience" through this wacky online video phenomenon.
In the run up to Christmas 2006, Sony decided it would try to create a "viral video" that would promote the PSP - it was basically a dorky guy in a Santa hat making a pitiful attempt to rap about how he wants his parents to buy him a PSP. A fantastic example of a vaccine video at its best...