Andrew - MAJOR SPOILERS
I will be the first to admit I love extreme horror films as well as ALL types of films in general. This movie was very strong: intense, well-acted, well-paced, well-photographed, well-everything. Splendid work. I love Joel Edgerton and can't wait to see more from him.
However, as a mother of a 4-year-old boy, I simply could not get past the killing of the baby. Especially (I think?) when the little boy was not even sick in the first place (wasn't Travis the one who was infected all along?). It made me physically sick to my stomach, especially hearing the young mother's devastating anguish and seeing his father fighting back so hard for all their lives. I'm well aware that this strong reaction I'm having was the director's intention, and I respect his art. However, I don't think I can ever watch this again, simply because of this. Just my own opinion, I don't disparage anyone else who liked this, because I really, really did, too.