Hepatitis C primarily spreads through contact with an infected person's blood, according to WebMD. Common methods of transmission include sharing hypodermic needles, getting a shot with a contaminated needle from a doctor in a developing country, receiving a tattoo with unsterilized instruments, and blood or organ transplants from unscreened donors.
Hepatitis C does not pass through casual contact and is unlikely to pass through sexual contact, as long as the couple is monogamous, according to Medline Plus. In some rare cases, a mother passes the virus to a baby during birth.
The United States began screening the blood supply for hepatitis C in 1992, according to the Centers for Disease Control and Prevention, substantially lowering the risks of transmission of the disease.