Stage Two: Vampiric Coma. Within 24 hours of being bitten, the victim will slip into a vampiric coma. During this phase, the pulse slows, breathing is shallow and the pupils are dilated. The large numbers of people mistakenly buried alive while in vampiric comas gave rise to the myth that vampires sleep in coffins. While it is commonly thought that anyone infected with HVV turns into a vampire, in fact only a small percentage of people survive vampiric comas. Generally, the young, the old and the feeble never come out of their vampiric comas and eventually die. The vast majority of people who survive vampiric comas are males between the ages of 18 to 35. Vampiric comas last about a day; the victim usually comes out of the coma the night after its onset. The vaccine is 50 percent effective when administered during Stage Two of the infection: the longer the victim has been in the coma, the less effective the vaccine.