I liked Contagious. I really like the idea of different kinds of zombies as the virus progresses, and I'm super-intrigued with the idea that a virus can turn people into zombies. 
 So while I initially REALLY LIKED Contagious, now...my feelings are a little more mixed. 
 I thought Orissa was selfish and really unlikable. She didn't always think about her actions, and sometimes went running off to save everyone, especially if it meant taking down some zombies. Granted, it is the zombie apocalypse...but don't act like an idiot. Honestly? Orissa really felt like this amazing, perfect super-girl that everyone loves. She's definitely sort-of Mary-Sue-ish. 
 There were some inconsistencies throughout the book too. The one that immediately comes to mind is how the character has her appendix taken out and is out for a month at the very beginning of the novel, but gets a severe concussion and gets stabbed, plus a couple MAJOR cuts (one in her hand, one in her head) in a matter of days and keeps going. The water is (allegedly) contaminated, so they can't drink it, and yet they use that same water to take their showers and to CLEAN OPEN WOUNDS. Plus, the zombies are zombies because a virus, and yet they're not wearing personal protective gear like gloves or goggles. I know gloves and goggles aren't cool when you're fighting zombies...but when it's caused by a virus we know nothing about, it just seems like a bad idea. 
 Speaking of the virus, we don't know anything about it. The group that Orissa joins up with is trying to find a vaccine; there are also some theories about the virus that don't go anywhere in this book. I kind of wanted to know more about the virus. 
 The other characters didn't really stand out, and it felt like they were just there. 
 Final Thoughts: I did like Contagious, even if my feelings toward it aren't as strong as they were right after finishing it. Orissa was easily the most irritating character, and there were things that went nowhere or didn't make sense, but the idea of a virus that turns people into zombies and the idea that as the virus progresses, your zombie-ness changes. I'm intrigued but I don't know if I'm intrigued enough to continue the series. Contagious gets 3 stars.