@LetMeDoStuff It's not 'standard' like a nuke or zombie outbreak, not even a death virus. Just nature and its grindstone finally bringing humanity down to size. Medication and biochemistry can no longer keep us in good health - the common cold become a threat, more dangerous ailments became deadly as our bodies - having weaker immune systems due to our use of drugs - cannot deal with the pressure.
Those who live are those who are naturally immune and resistant - the world is now as it once was, governed by chance and evolution. Plant life has taken back most of the land and wildlife has become balanced as predators and prey are now free to roam rather than domesticated or farmed.
Perhaps (and all that follows is just brainstorm) a common goal for one person is to find someone they believe to still be alive. The goal for a small town may be to find enough fuel to start the back up generators. A secretive corperation may still be active somewhere in the world - I kidnapping the immune and using them to their benefit.
The world has never and will likely never have an over bearing goal that everyone aims for, but as the RP's title suggests it is to recover and restore some form of civilisation and community across the globe.