Movie was TERRIBLE. Don't read unless you want a bunch of stuff spoiled, but really you should NOT see this piece of crap.
spoiler (click to show/hide)
They don't explore the repopulation idea very much at all. The beginning is a good set up with Robert Carlysle's character, showing what he had to do to stay alive during the original infection outbreak- basically abandon his wife and friends to die. Then his kids show up, sneak out to their original house and find the wife apparently uninfected up in the attic all insane. She's a carrier for the infection, and then dad sneaks in to see her, kisses her and ends up with the virus again. They could have explored a really cool idea with maybe his trying to redeem himself but instead turn him into a zombie 1/3 of the way through the movie.
Then they shift the focus to the kids and a few other survivors as the military decides to blow everyone up. The kids are boring characters that I didn't care about at all and was actively rooting for them to die over the last 1/3 of the movie.
Overall I would give this a 4 out of 10. For comparison, I would give the original an 8.5 out of 10. Also, people who like to bitch about shakey cam should not see this movie. I personally don't mind it so much when done right or for the right reasons, but this movie fails at both.
In conclusion, don't see this movie. If it bombs, we will be spared the horror of a 28 Months Later.