In a way, 220 volts is not any more dangerous than 110 volts, or even 10 volts. When it comes to damage to the human body, the amount of current flowing is more important than the amount of voltage that current possesses.
Current, the flow of electrical energy between two points, is what causes bodily damage when a human being is shocked. Voltage is a measure of the amount of force flowing between two points in an electrical circuit. Higher voltage means the current can flow more freely. Therefore, voltage is related to current, and, by extension, the amount of danger a given jolt of electricity presents.
However, circuits also contain resistance, a measure of the amount of friction preventing free flow of current. An object with 110 volts may actually be more dangerous than one with 220 volts if the second object has high resistance and the first has low resistance.
Furthermore, differences in body chemistry and fat composition contribute to the amount of danger any given current presents. These idiosyncrasies make it difficult to be precise about how dangerous a given voltage actually is to a specific person.