Don't waste your time on this. Go read Black Tide Rising or Monster Hunters International. Pride and Prejudice. Moby Dick. Anything. You'll thank me, and all the other people who have appropriately reviewed this horrible novel at the one star it earned.
Bad mechanics. Stupid politics. Poor plot. Unbelievable cliched bad guys (oh, this writer does NOT like Christians, hoo boy). It's a zombie novel that comes off anti-gun, but in which the characters carry and use guns, including the climax (darned monster of a Christian gets their just deserts).
It's a shame because the set up was interesting. The characters and world building had quite a lot going for it. However, the writers lack of understanding of basic physics and the world outside of Berkeley California combined with a clear and abiding loathing for Christianity (hey, I'm not Christian, but the degree of vitriol in this book was impossible to ignore), the United States and the US Military completely destroyed what they set out to do.