We all know that Sheldon is very careful about germs and does not go around the sick people. That is why he declines to go to hospital. In the episode "The Engagement Reaction" (Season 4, Episode 23), where Howard's mom fell sick, Sheldon says:
Leonard: Sheldon, Let's go!
Sheldon: To the hospital?!
Sheldon: Full of sick people?!
Sheldon: Oh, I do not think so?!
In the latest episode of current season "The Viewing Party Combustion" (Season 9, Episode 21), he goes to hospital and there are many instances of this. What changed? How come he goes to hospital now even he has germ-phobia and used to decline to go to hospital?