In a tabletop RPG I'm GM-ing, I have a far-future doctor who has found himself trapped on a world just beginning its Industrial Revolution (he hasn't really traveled through time, he's just crashed his spaceship) with only a futuristic first-aid kit and his wits, trying to cure a cholera-like disease that's going around town. He doesn't have a whole lot of time to get this done either.

Inventing antibiotics is out of the question; he doesn't have time to pick apart every common fungus to find which ones produce the most useful bacteria-killers (this isn't Earth, there's no penicillium).

I was thinking that he could instead find a way to inactivate the bacteria and make a vaccine out of them. How could he do this and how long would it take?

Also, the plot here is that they're chasing after a downed satellite that's emitting ionizing radiation; could that be used to kill the not-cholera without destroying the antigens marking it and produce a whole-cell vaccine?

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    $\begingroup$ The way you phrased the question, I thought you were referring to Dr. Who. That's all, nothing constructive to add. $\endgroup$
    – ozone
    Dec 6, 2015 at 1:29
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    $\begingroup$ Technically, you fight bacteria with antibiotics... $\endgroup$
    – Thucydides
    Dec 6, 2015 at 4:12
  • $\begingroup$ You can vaccinate against bacteria as well. $\endgroup$
    – Schilcote
    Dec 6, 2015 at 4:43
  • $\begingroup$ His most useful weapon would be his knowledge of disease vectors. Even if he couldn't come up with a cure, he should be able to identify the method of transmission and then take steps to prevent further infection (e.g. isolation of patients, boiling water before use, sterilization of equipment, etc). $\endgroup$
    – Steve Bird
    Dec 7, 2015 at 12:53
  • $\begingroup$ I agree with @ozone. Just use his sonic screwdriver to modify a canopener to manufacture it. $\endgroup$
    – JDługosz
    Dec 7, 2015 at 16:57

3 Answers 3


Well, one way of making a vaccine is heat-killing bacteria and thus making them non-infectious.

One alternative to attenuated vaccines is a killed or inactivated vaccine. Vaccines of this type are created by inactivating a pathogen, typically using heat or chemicals such as formaldehyde or formalin. This destroys the pathogen’s ability to replicate, but keeps it “intact” so that the immune system can still recognize it. 


So that could work in your scenario. The time needed is difficult to guess - he'd probably want to make a culture from the blood of an infected person and use that for the heat treatment. That could take a few days for growing the bacteria. In a pinch, and with the right bacterium, and if everything works directly, a day or two could work.

Note that this is not really an estimate - this is the very best case scenario that is highly unlikely. But if people are dying around you, you are not going to do randomized, double-blind studies first. You're just going to take some victim's blood, get a bacterial culture going heat kill it and hope for the best in your first patients. Some or all might die. This might not work, etc.

It would help if your doctor carried some basic microbiology supplies - some Petri dishes or flasks and growth medium, for example. Some bacteria will grow a visible colony after a day, some after 5 to 7. Your doctor will have no idea what colony is from the bacterium he wants, and whether it even grew at all.

To get enough for all patients, he'll need to grow a lit of bacteria, because he has no idea how much he needs to stimulate an immune response. So depending on the size of that "town", this could take weeks to months.

Another good bet, though, are two other vaccine methods:

First, the way the tetanus vaccine is made, it's not against the bacteria, it's against its toxin. For example, you could have a bacterium that produces a toxin, that in very low doses and inactive can be given to someone to inoculate them.

This is how tetanus vaccine is made:

Toxigenic strains of C. tetani are grown in liquid media, the toxin is purified, and then inactivated by treatment with formaldehyde to produce the toxoid antigen.


The purification step is something your doctor really won't be able to reproduce, though. But heat-killing the bacteria in such a solution of bacteria and toxin might work for your disease.

Second, the smallpox way. Have another disease in your town that is similar to your deadly disease, but that people survive. The way that cowpox was a mild disease, but smallpox was a dangerous disease. Infect people with the less deadly disease to inoculate against the deadly one. You might have a story about the people who survive being from a different town where the had a childhood disease that now protects them etc. For smallpox, it was the milk maids who somehow didn't get smallpox because they had been exposed to cowpox.

  • $\begingroup$ Devising the right amount of inactivation (no matter if by heat-killing or radiation) - even verifying if you have a proper vaccine - requires actual experimentation on people and will generally take a time measured in years, not days. It is also likely that in the process some of them will die, so the vaccine development may be stopped for political reasons and not result in anything even if it technically would be effective. $\endgroup$
    – Peteris
    Dec 5, 2015 at 20:11
  • $\begingroup$ Sure, but we are talking about the good case scenario in a desperate situation, right? In that case, cultivate the bacteria, try to heat kill them, then inject someone. Of course it's going to take a lot longer to do that with a whole village and some might die - and it might not work. But the OP is only asking whether something like that is possible at all, I think $\endgroup$
    – YviDe
    Dec 5, 2015 at 20:17
  • $\begingroup$ @YviDe No, I'm interested in practicality discussions as well. This is happening in a mid-size city, by the way, not a village. $\endgroup$
    – Schilcote
    Dec 5, 2015 at 20:38
  • $\begingroup$ @Schilcote okay, sorry I misunderstood. I have added a bit more information and two other options you could explore in that scenario $\endgroup$
    – YviDe
    Dec 5, 2015 at 20:50
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    $\begingroup$ (Some) desperate people will try desperate remedies. A doctor with a working vaccine against a plague will find some takers, and they'll call him a miracle worker if they stay alive while all round them people die horribly. This, even if the vaccine infects rather than protects a smallish fraction of its recipients. $\endgroup$
    – nigel222
    Dec 7, 2015 at 9:44

Modern vaccines are made by exposing living virus to very specific amounts of radiation in order to weaken it.

Theoretically, the doctor could do the same thing.


The amount of radiation is very, very specific. Too much, and the virus in question is killed, and will not stimulate the immune system to react to it.

Too little radiation, and the virus in question remains deadly.

Furthermore, each batch of vaccine would need to be irradiated. Keeping the radiation exposure constant, ensuring consistency across batches, etc ... that requires precision equipment. What else has your doctor brought with him? ;)


He'd presumably know about Jenner's original vaccine and the historical methods leading up to it, so he could reproduce that. Basically Jenner observed that milkmaids who had caught cowpox,hardly ever caught smallpox and almost always survived even if they did. So he innoculated people with pus from cowpox sores (yuk!), which provided them with protection against smallpox. (Sometimes it caused them to develop full-blown cowpox, but that's a minor illness compared to the highly lethal and always disfiguring smallpox, so it was a risk worth taking).

More generally, don't forget how primitive was medical knowledge at the time. A vaccine or drug that caused serious damage or even death to 1% of the people who used it, would be seen as well worth the risk if the alternative was known to be a 10% or greater chance of dying horribly from the disease it prevented. (Or would be so seen, once it was proved. Jenner faced much opposition to begin with. )

Even in the 20th century, treatment of Syphilis with horribly poisonous Mercury- and Arsenic-based drugs was preferable to suffering from and dying of tertiary syphilis. A safe alternative simply did not exist.

  • $\begingroup$ Sorry, I failed to note specific "Bacterial" in question. Smallpox is a virus. So this is a poor answer. Will leave it for now as may be of interest anyway. $\endgroup$
    – nigel222
    Dec 7, 2015 at 10:04
  • $\begingroup$ Well, that would work for a bacterium as well, as long as a sufficiently similar, but relatively harmless, disease existed. $\endgroup$
    – YviDe
    Dec 7, 2015 at 10:10

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