I think, the vaccination can be really interesting thing... It could br made from single medicine or as standalone item. If the disease can spread, you'll be able to prevent it.
For more realism, you must be able to vaccinate only for those threads, that you know about. And maybe you must deeply examine your diseased colonist (which will take some time and get a greater risk of death), to produce a vaccine.
After that, you'll be able to vaccinate all of your colonist to prevent (or have a higher ressistance, if full immunite is too cheaty) from that specific thread. You really must start from your doctors.
And one more thing. The diseases now a stricktly biome of your colony. And you couldn't have malaria at thundra. But if you capture fallen raider from faction, whose base located at jungles... and if the diseases will have latent period. And your warden contact with this prisoner for some time - who knows what might happen.
Same thing with wandering travelers or merchants (if they will be implemented)...
For more realism, you must be able to vaccinate only for those threads, that you know about. And maybe you must deeply examine your diseased colonist (which will take some time and get a greater risk of death), to produce a vaccine.
After that, you'll be able to vaccinate all of your colonist to prevent (or have a higher ressistance, if full immunite is too cheaty) from that specific thread. You really must start from your doctors.
And one more thing. The diseases now a stricktly biome of your colony. And you couldn't have malaria at thundra. But if you capture fallen raider from faction, whose base located at jungles... and if the diseases will have latent period. And your warden contact with this prisoner for some time - who knows what might happen.
Same thing with wandering travelers or merchants (if they will be implemented)...