Debunking the vampire myth

How science can explain the phenomena that led many people to believe in the undead

Legends of beings that defied death and preyed on the living date back to ancient times. Many early civilisations featured vampiric creatures in their lore, such as the child-eating demon Lamia of ancient Greek mythology and the life-sucking edimmu ghosts of Mesopotamian legend.

The belief in vampires became particularly common in the folklore of medieval Europe and persisted for hundreds of years, the superstitions often resurfacing during outbreaks of plague and other illnesses. But as our scientific understanding improved, the mysteries at the root of these beliefs were unravelled. Large fangs, hypersensitivity to sunlight and blood around the mouth could all be explained by then-unknown diseases and the natural process of decay after death. 

Fangs, sunlight and garlic

The classic vampires of legend have prominent fangs to pierce their victims’ necks, are nocturnal and have pale skin due to their aversion to sunlight. They can also be warded off with garlic. Thanks to medical advances, these days we know of several conditions that could actually explain some of these features. Porphyria is a group of conditions that may have contributed to the vampire myth. One type, called congenital erythropoietic porphyria (CEP), causes a toxic build-up of light-activated molecules in the skin. When sufferers are exposed to sunlight these toxins can eat away at the skin, damaging the gum tissue to make teeth look longer and fang-like. As well as Sun sensitivity, porphyria can also make people hypersensitive to foods high in sulphur, such as garlic. Similar symptoms can be experienced by those suffering from rabies, a deadly virus that can be transmitted to humans if bitten by an infected animal. Rabid people can develop insomnia, become aggressive – even trying to bite people – and demonstrate an aversion to strong stimuli, including bright light and strong smells like garlic. The diagnosis of rabies also fits the common depiction of male vampires pursuing female victims. The condition is seven times more common in men and can cause an increased libido by affecting the body’s limbic system.

Buried alive

Fear of the dead rising again meant that the living would sometimes take some rather macabre precautions to ensure this didn’t happen. Positioning a sickle around the body’s neck in the coffin, stabbing the corpse through the chest or slicing its knee tendons were just some of the methods used during burials to make sure the dead couldn’t escape. The belief that the dead might not stay that way was likely influenced by horrifying cases of people being buried alive. Poor medical knowledge meant that victims could be mistakenly declared dead and buried prematurely, only to regain consciousness when it was too late. For example, people with catalepsy can have seizures in which the body goes stiff and the breathing and heart rate slows dramatically, which could easily lead to a false diagnosis of death.

A thirst for blood

In times when people were wary of vampires, corpses were occasionally dug up to check they were still dead. People’s fears were exacerbated when bodies were found to have blood oozing from the nose and mouth. In reality, what looked like blood was actually ‘purge fluid’, the result of the natural decay process as the internal organs start to break down. Symptoms of disease also contributed to the blood-sucking myth. Tuberculosis (TB) is a bacterial infection that primarily affects the lungs and causes sufferers to cough up blood. Before the illness was understood people blamed these mysterious deaths on supernatural forces. The New England ‘vampire panic’ in the early 1800s, for example, was a TB outbreak that affected entire families. The deaths were blamed on the first victim of the family somehow feeding off their surviving relatives from beyond the grave. When they exhumed bodies to try and prevent what they assumed was vampiric activity, their worries were (mistakenly) ‘confirmed’ by the fact that TB victims would often be found with their mouths full of blood.


This article was originally published in How It Works issue 117, written by Jackie Snowdon


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