Hepatitis B and C
Viral hepatitis is a group of diseases of the liver that can be caused by consuming contaminated water or food (hepatitis A), using dirty needles or syringes (hepatitis B and C), or practicing unsafe sex (hepatitis B and in rare instances hepatitis C).
People infected with hepatitis can experience anything from no symptoms at all, to a mild illness, to serious liver damage. Most people recover completely from an infection, but some become carriers (hepatitis B and C) of the disease and can spread it to others unknowingly. It is especially important for women who are pregnant, or are trying to become pregnant, to get tested for hepatitis. If they are carriers of hepatitis B, their babies can be protected by receiving vaccination at birth.
Hepatitis B (HBV) is found throughout the world. It is most commonly spread through sexual contact with an infected person. Mothers who are infected can also pass it on to their babies. Household or family contacts of an infected person are also at risk for getting the infection. Health care workers may get hepatitis B if they are exposed (usually by a needle stick injury) to the blood of an individual who is infected.
Most people infected with the hepatitis B virus recover completely and develop lifelong immunity to the virus. A small number of people (approximately five to 10 per cent) become chronically infected and are “carriers” who can pass the infection along to someone else. Most of these people do not develop severe liver disease, although a small number do get cirrhosis and liver cancer. Fortunately new drug treatments are being developed to treat people with chronic hepatitis B. Approximately 90 per cent of babies born to mothers who are hepatitis B carriers have a high chance of developing chronic HBV, and often associated liver disease . This can be almost totally prevented by testing pregnant moms, and if they have hepatitis B, vaccinating their babies at delivery.
Hepatitis B can be prevented by getting a hepatitis B vaccine. Many provinces have adopted a universal vaccine program for school age children, and prenatal screening programs to ensure that infants of infected moms are vaccinated.
Canadian Blood Services tests every blood donation for hepatitis B. We use a test known as “HBsAg” that detects a specific part of the virus called the “surface antigen”. Starting with donations collected on April 9, 2005, we added a second test for hepatitis B known as “anti-HBc”. The anti-HBc test works by detecting antibodies produced by the human body in response to the presence of a “core antigen” of the virus. Only people who have been infected with hepatitis B (not those who have received the vaccine) will have this type of antibody. The introduction of this second test for hepatitis B will add a small, incremental margin of safety – over and above the current test we are already using. Only blood that passes both tests is sent to hospitals.
The hepatitis C virus (HCV) was first identified in 1989. Injection drug use and the sharing of drug paraphernalia is the most common way of getting hepatitis C, now that the blood supply is screened for the presence of this virus. You can also get hepatitis C through tattooing and body piercing. In Canada, it is estimated that between 210,000 and 275,000 people are currently infected with hepatitis C, of whom only 30% know they have the virus. At present there is no vaccine against hepatitis C.
More than half of people who get hepatitis C become chronically infected with the virus, but many of these people never develop severe disease, particularly now that there are effective treatments available. Sexual transmission of hepatitis C is very rare, even in couples who have been together for a long time, and although mothers sometimes pass the infection on to their infants, this is also rare. Health care workers may get hepatitis C if they are exposed to the blood of infected individuals through a needle stick injury
Canadian Blood Services tests every blood donation for hepatitis C. There are two hepatitis C tests used for screening donor samples:
- Anti-HCV, which detects antibodies to hepatitis C (implemented in 1990);
- Nucleic Acid Test (NAT assay) which detects the actual hepatitis C virus (implemented in October 1999).
Only Blood that passes both of these tests is distributed to hospitals.
Health Canada Resource