Just throwing out some examples on this post/More rambling yay!
IF you ever watch the news or read the paper or even just pay attention to science/Medical sites, there are multiple articles stored about certain illnesses changing.
It's why we get vaccines every year. The flu is one of the more obvious ones to point out. It changes at a rapid pace. So much so, the formula for the flu injected into you is a BRAND NEW mixture, not the same from last year.
There is no cure for influenza, we just have vaccines that can fight the bitchAs for other "incurables" right now such as AIDS and Cancers of varied types:
Cancer patients went through KEMO therapy, but a select few are trying out Radiation/Radioactive therapy. This isn't exactly "new" in the science world anymore(though it was announced in mid/late 2012). It seems "odd", because some cancers are created from radiation entering the body(mmostly being stomach, skin or blood cancer). There are other claims for possible "cures" in cancer, but none are truly confirmed to cure everyone.
As for HIV/AIDS, we should all know it's dangerous, yeh? Little tyke goes into your system, hops into Helper-T cells without detection because of its protein coat. Exchanged DNA and RNA codes and killed the Helper T cell after it leaves to continue to replicate and eventually shuts down your system. (Helper T cells are like the commanders of your immune system. They release a signal to all other immunity cells to attack x virus). So yeah. and if you have Full blown AIDS for like 15 years, you're fucked for catching a cold or even hayfever. So what could stop it? Right now,we have two things that kill AIDS/HIV. Classic Oxygen, as HIV/AIDS is fragile in air and cannot stay airborne for long. And we might have a possible cure for it, as seen
here on SourceFed.
but that's only two of like, what, infinite incurables?
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Going back to diseases relating to "treatment" of the Flu:
Sure, of x illness you can treat it. It changes, k use science and treat it again. No big. UNTIL you fuck up and have a pandemic/ an epidemic(depends on scale of infected) and start flipping tables because the illness was two steps ahead of you for once. They aren't predictable. They seem like it, but they aren't.
BUT WHAT ABOUT DA MAJICKS!?
Well, I kinda gave a FANTASTIC example earlier when relating with my helixes. Even if it was healing magic, it might not mix well with whatever illness is going around. And when that happens, you better have a plan B, C, D, E and F. Because some "possible" cures may not fit that shoe.
I'll just use my helixes again as an example. Okay, so they're a virus(technically they are lolol). So, let's just say one is the flu. You treat it and you'll have a select number of outcomes:
-Failure
--It's immune mofos.
-Success
--For now...
-Mixed results?
--The illness may be "beaten", but will leave side affects.
--The illness will mutate with the treatment, causing immunity all the way while turning into a new virus
--The illness will transmute the supposed treatment into something that will harm your body more so than help it.
--etc.
Because this is a sci-fi/fantasy roleplay, the mixed results answers can happen. Magic might mutate it, kill it, or even just spread it into the user who cast the spell in the first place.