Your reference for hepatitis C in Quebec
In addition to hepatitis C, there are four other viral hepatitises. They are identified by the letters A, B, D and E. These viruses are distinguishable by their modes of transmission, their risk of chronicity and the medications employed in their treatment.
The hepatitis A virus (HAV) is transmitted by ingesting water or foods contaminated with fecal matter from a person carrying the virus. It can also be transmitted via oro-anal sexual practices. Simply put, hepatitis A involves fecal-oral transmission. Hepatitis A presents no risk of chronicity.
Symptoms may be benign or severe and the severity increases with the age of the affected person. Symptoms include fever, fatigue, loss of appetite, diarrhea, nausea, abdominal pain, dark-coloured urine and jaundice. The disease generally lasts one to two weeks but can extend to multiple months in certain cases.
An effective vaccine exists (two doses) and the disease also confers lifelong immunity following infection. No specific treatment exists for hepatitis A. Only supportive care is implemented.
In Quebec, less than 50 cases of hepatitis A have been declared each year since 2011.
The hepatitis B virus (HBV) is mainly transmitted by blood, sperm or vaginal secretions from an infected person, even if the carrier is asymptomatic. Transmission may occur during unprotected sex, percutaneous contact with contaminated blood (sharing syringes, needles or razors), contact between a mucous membrane and blood, contact with sperm or vaginal secretions, or even during pregnancy via vertical transmission.
Hepatitis B can be acute or chronic. It becomes chronic for 95% of carriers who are children versus only 5% of adults, which is why it’s important to vaccinate newborns. Currently, a vaccine (three doses) exists with 98-100% efficacy; the disease also confers immunity following infection. There is no curative treatment for HBV, only supportive care to reduce the discomfort of those affected.
The hepatitis D (HDV) virus exclusively affects people who already carry the hepatitis B virus. The modes of transmission are similar to those for hepatitis B (blood, percutaneous and, more rarely, vertical).
HBV/HDV is the most severe form of chronic viral hepatitis. The HDV superinfection accelerates the development of cirrhosis by approximately 10 years in comparison to hepatitis B on its own. Patients suffering from a cirrhosis caused by HBD are exposed to a high risk of hepatocellular carcinoma.
Hepatitis D can be prevented by the vaccine for hepatitis B.
In 1989, Doctors Houghton, Choo, Weiner, Kuo, Overby and Granby discovered HCV. Following this discovery, a test was developed for detecting HCV antibodies. Blood testing greatly helped in preventing iatrogenic transmission. Later, polymerase chain reaction (PCR) testing technology made it possible to identify the virus’ RNA in its early stages (during the first acute phase of hepatitis C).
Strains of HCV are classed by six genotypes and numerous subtypes. In Canada, the genotype 1a is the most common.
In 2020, the Nobel prize in Physiology or Medicine was awarded to biochemist Michael Houghton and virologists Harvey J. Alter and Charles M. Rice for their discovery of the hepatitis C virus and other associated work.
Hepatitis E (HVE) is transmitted by fecal-oral contact, usually due to contaminated water. It can also be transmitted by animals as a result of ingesting insufficiently cooked meat (notably the liver and especially from pigs) or raw shellfish, mollusks and fish from contaminated water.
In most cases the infection resolves itself in two to six weeks. In some rare cases, HVE may result in fulminant hepatitis (acute liver failure), which can be fatal. Pregnant people with hepatitis E, particularly during their second or third trimester, have a heightened risk of liver failure, fetal loss and death. Up to 20–25% of pregnant people can die if they get hepatitis E in the third trimester. An effective HVE vaccine has been developed and licensed in China, but it remains unavailable elsewhere.
Un vaccin permettant de prévenir l’hépatite E a été mis au point et homologué en Chine, mais il n’est pas encore disponible ailleurs.