In Form and Void, the morning after the Rabid Infection of Superior, Nebraska starts, George is infected by a Rabid and his infection progresses quickly to the point that his whole face is covered with the black veins of a Rabid within a matter of hours. Despite the progression of the infection in George, he remains able to talk.
As George wanders through the streets of Superior, surrounded by dead Rabids and their victims, he hears a loud voice and follows it to where Sam Winchester's phone is playing a video. Sam approaches George from behind armed with a makeshift cattle prod and asks if George is still capable of speech. George is confused by this question and Sam shocks him unconscious and takes him to the local hospital where he is researching a cure on the Rabid infection. Sam questions George on the infection and George agrees to talk if Sam will give him something real to hold in his hands: a pudding cup. Sam complies and George eats the pudding and explains that the Rabid infection progresses at different paces, with some people getting infected quickly and others slowly but it all ends with them going psycho and dying. Sam insists that he will find a cure, but George believes that there is no hope and tells Sam that if he is smart, he will kill George and then himself.
Later that night, while on the phone with Dean, Sam looks over to where George has recently succumbed to his infection and died. Sam eventually lays George's body on a bed and covers him with a sheet. As Sam's own infection gets to the point of consuming him, he briefly glances at George before something Billie said gives him an idea on how to create a cure.