The vaccine currently used against hepatitis B infection is
**Core Concept**
The hepatitis B vaccine is a recombinant vaccine that utilizes a portion of the hepatitis B surface antigen (HBsAg) to induce immunity against the hepatitis B virus (HBV). This vaccine is a crucial tool in preventing HBV infection and its associated complications, such as liver cirrhosis and hepatocellular carcinoma.
**Why the Correct Answer is Right**
The correct answer is a recombinant DNA vaccine that contains a gene encoding the HBsAg. This gene is inserted into a yeast cell, which then expresses the HBsAg protein. The HBsAg protein is then purified and used as the vaccine. When administered to an individual, the HBsAg protein stimulates the production of antibodies against the hepatitis B virus, providing immunity against infection. The recombinant DNA technology used in the production of this vaccine allows for a high yield of the HBsAg protein and minimizes the risk of contamination with infectious agents.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is not a vaccine against hepatitis B.
**Option B:** This option is incorrect because it is not a recombinant DNA vaccine.
**Option C:** This option is incorrect because it is not the currently used vaccine against hepatitis B infection.
**Clinical Pearl / High-Yield Fact**
The hepatitis B vaccine is a highly effective vaccine that can prevent HBV infection and its associated complications. It is recommended for individuals at high risk of HBV infection, such as healthcare workers, individuals with multiple sexual partners, and individuals with chronic liver disease.
**Correct Answer: C. Recombinant DNA vaccine containing a gene encoding the HBsAg.