What is Hepatitis C?
Hepatitis C (HCV) is an infectious disease affecting primarily the liver that is caused by the hepatitis C virus, a small, enveloped, single-stranded, RNA virus. When people refer to HCV, they are actually talking about a family of related virus strains. These unique strains all originated from a common ancestor virus but over the last few hundred years the virus continued to evolve differently around the world. These variations were adaptations by the virus to not just overcome but thrive in different environments.
Today, there are six major genotypes (or strains) of HCV and more than 50 subtypes. These genotypes share some common gene sequences (or traits) with other HCV genotypes, but differ in others.
Today the six major HCV viral genotypes are distributed throughout the world but in the United States genotype 1 remains the most common viral strain. Although, the different HCV genotypes generally act the same in how they infect people and cause disease, there can be distinctions in how each genotype responds to treatment.
How common is Hepatitis C?
Approximately 3.2 million people in the United States have chronic HCV. Infection is most prevalent among those born during 1945 – 1965, the majority of whom were likely infected during the 1970s and 1980s prior to the 1992 implementation of wider HCV screening of the donor blood supply.
How is Hepatitis C transmitted?
HCV is transmitted primarily through large or repeated exposures to infectious blood or body fluids such as:
- Injection drug use (currently the most common means of transmission in the US)
- As a recipient of donated blood, blood products, and organs; particularly prior to 1992
- Needlestick injuries in the health care setting
- Mother to child birth transmission from an HCV-infected mother (some statistics report a 4% rate of transmission for mothers positive with HCV)
- Unprotected sex with an HCV-infected person
- Unsanitary tattoo procedures with contaminated equipment
What are the symptoms?
The initial infection is often asymptomatic. Patients may experience non-specific, mild symptoms that are unlikely to prompt a visit to a health care professional. When symptoms occur, they can include:
- Dark urine
- Clay-colored stool
- Abdominal pain
- Loss of appetite
- Nausea and vomiting
- Muscle aches and joint pain
- Jaundice (yellowing of skin and eyes)
Of those that are exposed to HCV, 75% - 85% will become chronically infected. For a lucky few—about 15% - 25% of those exposed—the body will naturally clear the virus without treatment and no chronic infection results. The reasons for this natural immunity are not well-understood.
In the majority of infected individuals, chronic infection is established and a gradual chain reaction of liver damage, scarring (or cirrhosis) and loss of function occurs. In some cases, those with cirrhosis will go on to develop complete liver failure (resulting in the need for transplantation), liver cancer or life-threatening esophageal and gastric varices.
How is it diagnosed?
HCV infection is often not recognized until an asymptomatic person is identified as HCV-positive when screened for blood donation or when elevated liver enzymes—such as alanine aminotranferase (ALT)—are detected during a routine examination.
In May of 2012, the CDC issued a recommendation that anyone born between the years 1945 to 1965 should get a one-time blood test to see if they have contracted the hepatitis C virus. Baby boomers account for more than 2 million of the 3.2 million Americans infected with the blood borne virus. They represent a group of people that may have been exposed to HCV via the tainted blood supply or even a single experience of intravenous drug use or unprotected sex. Since it can take decades for any chronic symptoms to surface, the CDC is recommending that physicians be proactive in screening this subset of the US population. The US Preventative Services Task Force echoed this recommendation in June 2013.
The CDC officials believe the new measure could lead to 800,000 more baby boomers getting treatment and could save more than 120,000 lives. About 3 percent of all baby boomers are expected to test positive for the hepatitis C virus. A recent survey found that less than 25% of baby boomers have been tested for the virus.