First question so hope I'm doing this right! Working on a setting right now where a bio-engineered virus/plague is wiping out a large portion of humanity. Most died upon first exposure. Some survived, but are dying slowly, while a third group has developed complete immunity.

How could this immunity be passed on to the dying survivors? Would a blood transfusion do it, assuming that it was indeed something in the blood that made these people immune to begin with? Or would it be something more complex, like maybe their ability to develop some kind of antibody where others couldn't? (in which case the dying survivors would have to derive such antibodies from the immune survivors)


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    $\begingroup$ This is a fully baked procedure we can (& do) do now, & doesn't even need a whole blood transfusion (so no worries about blood types, because you centrifuge the red cells out first), the blood plasma & antibodies can be (& are) separated out from donated blood, for transfusion into others, if you can get a large enough antibody load into the sick person it can kill the disease off or suppress the disease long enough for their own immune system to gear up sufficiently to fight it on its own. Google it. $\endgroup$
    – Pelinore
    Oct 17, 2019 at 20:51
  • $\begingroup$ ^ worth noting that the more recently the donor has had (& recovered from) the disease the higher the concentration of the appropriate antibodies in their blood. $\endgroup$
    – Pelinore
    Oct 17, 2019 at 20:55
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    $\begingroup$ Here's another link Intravenous Immunoglobulin (IVIG) I got Googling those two words. $\endgroup$
    – Pelinore
    Oct 17, 2019 at 21:08
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    $\begingroup$ @Pelinore: Gotta be honest: that right there is an answer I’d upvote if it weren’t a comment... $\endgroup$
    – Joe Bloggs
    Oct 17, 2019 at 21:23
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    $\begingroup$ @Pelinore My experience has been that many of the answers on worldbuilding are "This already exists, here's how it works and where you can learn more" $\endgroup$
    – Muuski
    Oct 17, 2019 at 22:47

2 Answers 2


You have two easy and familiar routs where you could:

1. Biolife in the blood

This would be largely science fiction, but it would have "believability" for your audience. Some kind of proactive lifeform in the blood, such as a bacterium, would fight to destroy the virus. Here, the blood is just the carrier and, while a transfusion could work, isolating the thing inside would be more efficient, allowing it to be distributed on a mass scale more easily.

That could use "option exhaustion" to propel the plot and give you the scientific breakthrough needed for victory, either for the protagonist or a helper.

Something similar was done in Deep Space Nine, Season 1 (ep13 'Battle Lines'), where the spiritual leader Kai Opaka died on a remote moon, but was brought back to life by nanites in the atmosphere. Nano-tech is a stretch, but bacteria is more believable and adaptable.

2. Vaccine

Vaccines are basically made from dead viruses. The blood of someone immune would probably have traces of it, or antibodies for the virus. But, it may need engineering and would require blood type matching. A transfusion itself probably would't work very often if at all, the plot would keep waiting for a scientific analysis of the blood to make a vaccine.

This is similar to what started at the end of I am Legend with Will Smith. Although that blood sample did contain a kind of vaccine he had introduced into the blood.


Yes, in fact we already sort of do this. During the Ebola outbreak, medical workers that survived had the antibodies in their blood separated from the red blood cells and injected into other people that way their own bodies could start building up an immunity to it and the immune system can start fighting the virus.

Of course, this is a simplified version of the process but the general idea is very similar, as long as the disease doesn't mutate or at least mutates so minorly that the antibodies are still effective they could theoretically use this method.


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