Simplify the following text for a Grade 8 native English-speaking person.
Original: An estimated 270-300 million people worldwide are infected with hepatitis C. Hepatitis C is not known to cause disease in other animals . No vaccine against hepatitis C is currently available .
Simplified: about 150-200 million people in the world are infected with hepatitis C. Hepatitis C is the leading cause of liver transplants in the United States .