You can become infected with hepatitis C if you come into contact with the blood of an infected person.
Other bodily fluids can also contain the virus, but blood contains the highest level of it. Just a small trace of blood can cause an infection.
At room temperature, it's thought the virus may be able survive outside the body in patches of dried blood on surfaces for up to several weeks.
The main ways you can become infected with the hepatitis C virus are described below.
People who inject drugs, including illegal recreational drugs and performance-enhancing drugs such as anabolic steroids, are at the highest risk of becoming infected with hepatitis C.
Almost 90% of hepatitis C cases in the UK occur in people who inject drugs or have injected them in the past. It's estimated around half of the people in the UK who inject drugs have the infection.
The infection can be spread by sharing needles and associated equipment. Injecting yourself with just one contaminated needle may be enough to become infected.
It's also possible to get the infection by sharing other equipment used to prepare or take drugs – such as spoons, filters, pipes and straws – that have been contaminated with infected blood.
Less common causes
Hepatitis C may be transmitted during sex without using a condom (unprotected sex), although this risk is considered very low.
The risk of transmission through sex may be higher among men who have sex with men.
The risk is also increased if there are genital sores or ulcers from a sexually transmitted infection, or if either person also has HIV.
The best way to prevent transmission of hepatitis C through sex is to use a male condom or female condom.
However, as the risk is very low for couples in a long-term relationship, many choose not to use a condom.
If your partner has hepatitis C, you should be tested for the condition.
Blood donations before September 1991
Since September 1991, all blood donated in the UK is checked for the hepatitis C virus. If you received blood transfusions or blood products before this date, there's a small possibility you may have been infected with hepatitis C.
Blood transfusions and treatment abroad
If you have a blood transfusion or medical or dental treatment overseas where medical equipment is not sterilised properly, you may become infected with hepatitis C. The virus can survive in traces of blood left on equipment.
Sharing toothbrushes, scissors and razors
There's a potential risk that hepatitis C may be passed on through sharing items such as toothbrushes, razors and scissors, as they can become contaminated with infected blood.
Equipment used by hairdressers, such as scissors and clippers, can pose a risk if it has been contaminated with infected blood and not sterilised or cleaned between customers. However, most salons operate to high standards, so this risk is low.
Tattooing and body piercing
There is a risk that hepatitis C may be passed on by using tattooing or body piercing equipment that has not been properly sterilised. However, most tattoo and body piercing parlours in the UK operate to high standards and are regulated by law, so this risk is low.
Mother to child
There is a small chance that a mother who is infected with the hepatitis C virus will pass the infection on to her baby. This happens in around 5% of cases. It's not thought that the virus can be passed on by a mother to her baby in her breast milk.
There's a small – approximately 1 in 30 – risk of getting hepatitis C if your skin is accidentally punctured by a needle used by someone with hepatitis C.
Healthcare workers, nurses and laboratory technicians are at increased risk because they are in regular close contact with blood and bodily fluids that may contain blood.