There are certain advantages to being a walking corpse. One of the biggest is a natural immunity to most diseases. AIDS, cancer, influenza and other illnesses mean little or nothing to the undead.
But immunity to disease doesn't mean the vampires can ignore diseases. Any illness that can be transmitted by the blood is a potential problem for vampires, because they can carry the illness and transmit it from victim to victim. Indeed, several Kindred in Haiti and the US have become active carriers for the HIV virus. By drinking from someone infected with the HIV virus and then feeding on different victims, these vampires have helped to spread an already rampant infection. In some fiefdoms any vampire found carrying HIV is locked away for the good of the herd. In rare cases such carriers have even been put to Final Death for spreading the disease. Such plague-dogs are frowned upon heavily in the Camarilla, for not only does disease threaten the human populace, but victims of the disease might speak of their affiliation with vampires, putting the Masquerade in grave danger.
Vampires with the Medicine Knowledge are sometimes recruited by the primogen in major cities to regulate the spread of disease through the Kiss. In the past decade, such vampires have been invited to speak before conclaves, alerting elder and neonate alike about noticeable signs of drug abuse and obvious physical symptoms that vampires should try to avoid. Even the vampires of the Sabbat, with their lack of concern for the herd, have begun to consider regulations regarding disease carriers.
An Intelligence + Medicine roll (difficulty 7) will allow characters to detect the presence of HIV, hepatitis or other blood-related diseases. If the roll is failed, the vampire does not notice the symptoms and exposes himself to disease (Stamina roll,difficulty 6, to avoid). A botch indicates the character feeds sloppily and automatically becomes a carrier for the disease. Kindred legends speak of certain plagues potent enough to affect vampires. Very few vampires have any knowledge of such ailments, and those who do are highly prized. Despite the Kindred's formidable powers, they are ill prepared to handle the occasional illness that can cause them harm.