“Carrier” is a term often mentioned when we talk about liver disease. What is a “carrier ”? How is this state generated? How is it detected? Also, why is it harmful to be a carrier?
When the hepatitis B virus (or any virus) enters the body, our defense system (i.e. immune system) will respond immediately by sending out antibodies to deal with the intruders (i.e. viruses). If the antibodies win the battle, the virus will be wiped out. The person does not become ill as long as the antibody level remains above 10 IU/L. However, a person should have a booster vaccine if his/her antibody level is below 10.
If the level of antibodies remains low after six months, the body will produce another substance called “antigen” to help fight against the virus. Although antibodies and antigens both protect the body from viral invasion, they cannot co-exist peacefully. There will be no antibody when antigen is present. Antigen is a type of antibody that is more neutral. Antigen will try to negotiate with the virus, establishing a “non-aggression pact”. If the antigen cannot wipe out the virus, the virus will remain inside the body without interfering with the body. At this time the body has become a “carrier”.
However, if a person’s immune system has been weakened (for example the person became ill due to another disease) then the originally non-invasive hepatitis viruses may start attacking the body. Therefore being a carrier is similar to living with your enemy. If your immune response successfully eliminates the subsequent pathogen, then the hepatitis virus will continue to be dormant and stay in the human body until another opportunity for invasion comes.
How would I know if I am a carrier? A single blood test can tell. If the blood test result returns positive, then you are a carrier and has the ability to spread the virus to others.
Content by Dr. Francis Ho, Family Practice