Vampires are known to be humanoid creatures to whom the nutrients in blood are essential.

I will assume that, for the purpose of this question, vampires are entirely human but consume blood, may it be for reasons of culture or survival.

As is widely known, many highly dangerous diseases such as malaria, hepatitis and HIV can be transmitted via blood.

How must the biochemistry of vampires change, in comparison to humans, so that they can protect themselves from such diseases?

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    $\begingroup$ Many highly dangerous diseases such as malaria, hepatitis and HIV can be transmitted via blood transfusions. Drinking blood is a totally different process, and the hydrochloric acid in the stomach will make short work of such unarmored pathogens. (Some pathogens and parasites have special means of protection, enabling them to pass through the stomach without being killed; but they are not the focus of this question.) You cannot catch malaria, hepatatis or HIV by eating the stuff. All vampires should is avoid feeding when they have open wounds in their mouths. $\endgroup$
    – AlexP
    Oct 29, 2019 at 9:43
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    $\begingroup$ Possible duplicate: How would vampires avoid contracting diseases? Some of the answers are relevant, though the accepted one perhaps is not. $\endgroup$ Oct 29, 2019 at 9:45
  • $\begingroup$ @AlexP Would a mucous membrane, such as in the mouth, not suffice? $\endgroup$ Oct 29, 2019 at 9:57
  • $\begingroup$ Maybe yes, maybe no. For malaria, definitely no. For certain types of hepatitis, yes, but those types are not normally thought of as blood-bourne. For HIV, possibly, with a low transmission rate. $\endgroup$
    – AlexP
    Oct 29, 2019 at 10:22

1 Answer 1


First of all, some biological agents can infect a host only if propagated through the right way.

E.g. plasmodium malariae, the agent causing malaria, needs to enter the blood stream via a mosquito bite. For such cases the digestive system would process the agent as any nutrient.

Other agents might require a well defined biochemistry. I.e. the virus causing the SIV needed a mutation to become capable of causing HIV into humans.

It can also be that, for the same reason, some patogens which are harmless to humans would be virulent for vampires.


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