Was Ken Mattingly removed from Apollo 13 because of exposion to the flu?

No, Ken Mattingly was not removed from Apollo 13 due to exposure to the flu. He was replaced by Jack Swigert shortly before the mission because he had been exposed to the German measles, which posed a potential health risk to the crew in the event of an outbreak. Mattingly's removal was a precautionary measure, and he later played a crucial role in supporting the mission from the ground.