Intro to hepatitis C

Key points

  • Hepatitis C is a liver infection caused by the hepatitis C virus.
  • About one in four people clear hepatitis C on their own (spontaneous clearance), and the others go on to develop chronic hepatitis C.
  • Over time, the virus causes inflammation, destroying healthy liver cells and causing the liver to replace them with scar tissue. This happens in a process called fibrosis.
  • Over time, if the virus is left untreated, more of the liver gets replaced with scar tissue until nearly all of the liver is scarred; this is called cirrhosis.
  • There is no vaccination available against hepatitis C and there is no immunity to hepatitis C.

The word hepatitis refers to an inflammation (-itis) of the liver (hepa-).

Hepatitis C is a specific liver infection caused by the hepatitis C virus.

The liver

The liver is the largest internal organ in the human body and the primary site targeted by the hepatitis C virus. The liver performs over 500 essential processing functions. These include breaking down alcohol, drugs and other chemicals; regulating the supply of body fuel (glucose), hormones and essential vitamins and minerals; and making essential proteins for blood-transporting systems, blood clotting and immune function. The liver is also one of the few organs that can regenerate if injured.

The hepatitis C virus

The virus is an RNA virus. It uses liver cells to create copies of itself, killing those cells in the process. The infection was first labeled “non-A, non-B” hepatitis before the hepatitis C virus was identified in 1989.

Acute infection (phase 1)

Acute hepatitis C refers to the first phase of the disease, when a person is newly infected. At this stage, about one in four people with hepatitis C clear the virus from their body on their own within six months. These people no longer have hepatitis C, but they will still test positive for hepatitis C antibodies for the rest of their life. (For more information, see Diagnostic tests.) 

Chronic infection (phase 2)

About three of four people with acute infection do not spontaneously clear the virus within six months and the disease progresses to a chronic infection.

Inflammation and fibrosis

Over time, the virus destroys liver cells, causing inflammation of the liver and the formation of scar tissue within the liver. This is called fibrosis.

For most people, progression of the disease is slow, often over 20–30 years. During this time, a person may not show any signs or symptoms, even though the hepatitis C virus is injuring the liver. 


During the decades of chronic infection, more and more of the liver becomes scarred. When most of the liver is scarred, this is called cirrhosis. Once cirrhosis has developed it initially results in compensated cirrhosis. In this stage the liver is still performing many of its functions. Many people with compensated cirrhosis experience few or no symptoms. However, eventually decompensated cirrhosis develops. Decompensated cirrhosis is when there is so much scar tissue that it is difficult for the liver to function. In this stage there is a significant risk of life-threatening complications, such as serious abdominal infections, internal bleeding, liver failure and death. With this type of cirrhosis, a liver transplant might be considered.

People with cirrhosis have an increased risk of liver cancer called hepatocellular carcinoma (HCC).

Hepatitis C outside the liver

The hepatitis C virus can also affect organs in the body aside from the liver. It has, for example, been linked to an increased risk of kidney failure and pre-diabetes and diabetes. Healthcare providers usually recommend tests to monitor a person’s general health, not just their liver. 

Genotypes: Six strains of hepatitis C

A genotype is a major strain of the hepatitis C virus. There are at least six genotypes of the hepatitis C virus. Knowing the genotype is part of the decision-making process for choosing a treatment regimen. Some treatments can cure any genotype of the hepatitis C virus and others can cure specific genotypes. 

Hepatitis C treatment and cure

Hepatitis C can be cured! Today, treatment cures more than 95% of people with hepatitis C. The best way to prevent worsening liver health and complications of cirrhosis is to get treated and cured of hepatitis C.

Everyone with hepatitis C should speak with their healthcare provider about their treatment options. For more information, see Hepatitis C treatment.

No vaccine and no immunity: A person can be re-infected

There is no vaccination available against hepatitis C and there is no immunity to hepatitis C. A person who had hepatitis C and spontaneously cleared the virus or was cured through treatment can be re-infected if they are exposed to the virus again. Hepatitis C antibodies do not protect against the virus.


Transmission of hepatitis C occurs through blood-to-blood contact. This means that hepatitis C is passed on when blood carrying the virus gets into the blood of another person. Today, most new hepatitis C infections in Canada happen when people use previously used equipment to prepare and inject drugs. Hepatitis C is not transmitted through casual contact such as kissing, hugging or sharing utensils.

In general, sexual transmission of hepatitis C is not common. The risk increases when certain factors are present, such as condomless anal sex, HIV, sexually transmitted infections, sex where blood is present, group sex and chemsex (using specific drugs to enhance or prolong sex). Thus, the risk of transmission may be higher among some groups of men who have sex with men (MSM).

(For more information, see How Hepatitis C transmission happens


An important part of the public health response to hepatitis C in Canada is to prevent new hepatitis C infections by:

  • providing prevention education, resources and services that enable people to reduce their likelihood of getting hepatitis C
  • encouraging people to get tested if they engage in activities that may expose them to the hepatitis C virus
  • connecting people with treatment services and offering treatment

Resources for service providers

Resources for clients

Revised 2019.