I don't know about the rest of you, but I think this sounds like an awesome concept for any game to have implemented- to have it be a regular part of the system! So it is now that I'm thinking up a game called "Last Men on Earth". The gameplay aspects are simple, you are in a world with no more government and a rising body count. Your goal is simple, which is to survive and somehow find a cure to the virus that plagues the earth.
I'd make it pay to play and an RPG, so that way people will be slightly less inclined to commit to biological warfare. People would be able to make entire civilizations in the hopes that they can stave off the infection.
Now, the virus would work in a very hilariously scary way. There'd be a couple of different forms of the virus, which makes you constantly second-guess who you talk to and where they've been.
First off, there would be "Infected Areas", which yield high level items but also have a high chance of becoming infected. Protective gear could be worn to properly traverse these Infected Areas, but even then, there's a decent chance of you being infected, and thus, having people not trust to be in the same room as you.
First variation of the Virus (codenamed HEX): The Virus would be an airborne virus that affects anyone who is in the same general vicinity as an infected person(s). This virus is the common version, where one in game day after infection, they would only have small effects such as the debuffing of strength, agility, etc. IT would be such a small and unnoticeable effect that an infected person really wouldn't realize they were infected.
Day 2 they start to have more noticeable debuffs, and their in-game avatar will develop boils.
Day 3 their health will start rapidly depleting as their skin becomes green and their boils pop, killing them.
That would be the common virus. The second form of the virus would be the "Carrier" virus, where a user would only be able to detect the virus with a special syringe device. There would be an unoticeable stat debuff with health, but otherwise you really wouldn't be able to tell if you had it or not. If you came back to your colony and everyone became infected, then you might actually be a carrier! The carrier does not die via the virus.
The game, despite being an RPG, would be solely PvP. Experience would be gained via PvP and other survival things, such as medical science or retrieving water, economies, etc. You'd be one individual fighting to survive with other individuals.
But ultimately, in order for the full effect and full amount of scientific progress to be felt, there has to be very very little restrictions on the game. The only thing you'd be unallowed to do would be to have sex. Otherwise, you would be able to shoot and kill anyone you saw fit.
