Hepatitis C is not contagious. It cannot be caught by any means other than blood to blood contact. The virus does not survive well outside the human body, which makes laboratory work difficult.

It is technically possible for the virus to spread by accidental contact with infected blood, but the chances are extremely small. A quantity of infected material has to be driven below the skin for the infection to transfer. Those with Hepatitis C are advised not to allow shaving items and toothbrushes to be used by others just in case. Spilt blood should be cleaned up with bleach or alcohol. Use of gloves during first aid is essential.

The virus is not transferred by heterosexual or oral sex. No additional precautions to prevent sexual transfer are recommended for couples in long term monogamous relationships. Whether the virus can transfer by anal sex is not clear, and almost impossible to research. Hence anal sex should be avoided, as should sex during menstruation.

The exception to the normal sexual transfer situation is where HIV/AIDS is also present, in which case Hepatitis C can transfer sexually. It is thought that the HIV switches off the body's local defences, and the Hepatitis C takes advantage.

The virus has been known to transfer across the placenta and infect babies in approximately 5% of cases where the mother has the virus.

In many cases (25%-40%), particularly where the quantity of infected material transferred is small, the virus is completely cleared by the body's immune system, leaving the person with antibodies to the disease but no active virus. Many infections do not develop into the full virus itself.

Nearly all current cases can be traced to infected blood transfusions, infected blood products, or intravenous drug abuse. A few can be traced to tattooing, piercing or electrolysis. There is a remote possibility that the virus could be transferred by shared cocaine straws.