One thing that tends to be a consistent in most stories regarding this genre would be the finality of infection. If someone gets bitten, scratched, or in some other way infected, it is only a matter of time before his or her demise. While this is great for a movie or a tv series, it is not so good for a RPG that is trying to be an ongoing campaign.
|Artwork © 2008 Jeff Freels, used with permission|
There should always be a fear of dying or contracting the disease. If that possibility did not exist, I guess it would not be the same. In game terms, that really cannot be something that can be acceptable as black and white. While that same finality should in some always be present, there needs to be some gray area - a chance for survival. Either that or the players could end up starting new characters semi-frequently. But then again, that is always a reality in most RPGs.
So I see Resistance as a character's ability to not only have some possible immunity to the crap going on, but also a bit of luck like a bite not actually getting through the clothes as initially thought. Throw in some possible mutation effects like PSI powers that could develop from some exposure to the environment, and there could be something that could last a number of campaigns.
Now - immunity or resistance to another bullet, that is something that will not be as easy to do. As society degrades and the zombies become the environment, dealing with other human beings will be far more dangerous.