What is Hepatitis B Surface Antibody

Hepatitis B surface antibody is a protective antibody that stimulates the body's immune function, can offset the harmfulness of the hepatitis B virus, and prevent the human body from being harmed by the hepatitis B virus again. After being injected with the hepatitis B vaccine, most people will produce hepatitis B surface antibodies. Generally, this antibody can last for 3 to 5 years, and some people can maintain it for more than ten years.

1. Generation time

Because infants and adults have different immune response sensitivities, some people are more likely to produce surface antibodies after vaccination, while some people will not produce surface antibodies. About 30% of people will produce surface antibodies after the first dose of the hepatitis B vaccine, while about 50% to 70% will produce surface antibodies after the second dose, and about 90% will produce surface antibodies after the third dose.

2. Maintenance time

There are two ways to produce hepatitis B surface antibodies: one is produced by the injection of hepatitis B vaccine; the other is produced by being infected with the hepatitis B virus and then recovering. However, the antibodies produced by the injection of hepatitis B vaccine are not permanent. They generally last for 3-5 years, and in a small number of people they can last for more than 10 years.

3. Antibodies disappear

The hepatitis B surface antibody was negative and the antibody disappeared. Whether the hepatitis B vaccine administered in the past still has a protective effect can be determined through blood tests. If the hepatitis B surface antibody is negative, it means that no antibodies are produced after vaccination or that antibodies have been produced but have disappeared. This group of people should get three doses of hepatitis B vaccine. If antibodies are produced but the level is low, it means that the protective effect is weak and they can get another dose of hepatitis B vaccine, which is a booster shot.

If the antibody is positive and the antibody titer is high, it means that the original hepatitis B vaccine still has good protective efficacy and there is no need to receive the hepatitis B vaccine again. In addition, although some people's hepatitis B antibody test results are negative after vaccination, the antibody titer increases significantly after another shot of the vaccine. This situation indicates that the body still has immune memory of the original vaccine, so another shot of the vaccine is enough.

4. Antibody titer

Whether the human body's resistance is sufficient to fight the invasion of hepatitis B virus requires that the hepatitis B surface antibody maintain a certain level in the blood, that is, maintain a certain hepatitis B surface antibody concentration, which is the hepatitis B surface antibody titer. If the hepatitis B surface antibody titer is too low (below 10mIU/ml), it may lose its protective effect and the human body can still be infected with hepatitis B.