Just finished it - 3 days. Awesome awsome awesome. This is Stephen King's the Stand 30 years improved.
Justin Cronin our next best seller, fabulous story teller and a tremendous epic tale. Please stay with this genre - you are fabulous. Thrilled that you have left the door open, I think the wait for a sequel will be a match for Robert Jordans final chapter!
Will be picking up your second novel as this looks like it might be nearly on par (though not the genre).
I'm hooked and happy to help make you a millionaire!