Everfree - Nick Sagan

A small group of humans has survived the apocalyptic epidemic called Black Ep that ravaged the world. These survivors start to wake others who'd been cryogenically preserved to await a future when the disease might be cured. At first, everyone agrees on the basic principles of this new world - how lucky they are to have survived, how they're all in this together, how they should look out for each other, learn from the past and build a better world...

But inevitably, as more sleepers are roused, there are some who disagree. People who have knowledge of power are waking up to a new world, and they do not intend to wait politely in line. But as this new utopian starts to fracture, one more surprise lies in wait for the survivors. It comes from a very very long way away indeed - and its impact is such that it will transform the future foreveryonein this post-plague, perhaps even post-human, world...