Description
The freeze-dried live attenuated hepatitis A (HepA) vaccine is a lyophilized preparation containing a weakened (attenuated) strain of the hepatitis A virus (e.g., H2 strain). The virus is propagated in human diploid cells, harvested, purified, and then freeze dried for stability and extended shelf life. When reconstituted with sterile water for injection, it is administered as a single dose, usually subcutaneously. This live attenuated form mimics a natural infection, stimulating the immune system to produce long-lasting antibodies and cell-mediated immune responses without causing the actual disease. It is primarily used in regions like China and India for active immunization in individuals, often children above one year of age.
Target Diseases
- Inflammation of the liver
Dosage Schedule
The standard hepatitis A vaccination schedule consists of a 2-dose series, with the second (booster) dose administered 6 to 18 months after the first. A combination hepatitis A and B vaccine uses a 3- or 4-dose schedule
Possible Side Effects
- Common side effects of the Hepatitis A vaccine are mild and include soreness
- redness
- or swelling at the injection site
- mild fever
- headache
- fatigue
- and loss of appetite
Contraindications
- The freeze dried live attenuated hepatitis A vaccine is generally safe
- but there are specific contraindications
- primarily related to allergic reactions and the recipient's immune status.