Mr Cartwright is lecturing on "The Vampire on Screen: Myth, Magic and Ideology", a paper offered by the University of Otago's media, film and communication department as part of Otago's summer school.
All 36 places on the course have been taken.
Part of the vampire myth's appeal was to teenagers, and the highly popular Twilight film series had focused primarily on a youthful audience, he said.
But tales about vampires had existed since "almost the dawn of recorded history".
And vampire myths ultimately connected with many ages, appealing, not just teenagers.
Mr Cartwright said it was hard to explain exactly why vampire stories on film and television had become so popular, but vampires had "never been healthier".
In Western countries, including New Zealand, people were often reluctant to discuss death or face its eventual reality.
The modern world also often appeared to be highly ordered and "incredibly rational", but vampire myths reflected impulses which were not strictly rational, and dealt with things that could not be rationally explained, he said.
Through such stories, viewers encountered "uncertainties about death", but ultimately managed to remain "very safe", given that many films were "obviously escapism".
Vampire myths reflected underlying human anxieties and concerns and indicated something of "broader society", changing over many generations to reflect the preoccupations of each era.
"They're very much part of who we are." They embodied an element of "repulsiveness", but modern depictions often also portrayed them as rather attractive, and sometimes even as somewhat "sexualised creatures", who might take off their shirts before seeking a little more blood.
"There's something appealing about living forever and having supernatural strength, and never ageing."