Freeze-dried Live Attenuated Hepatitis A Vaccine (720ELISA) (Medical Monograph)

Overview

A single-dose, live attenuated viral vaccine derived from the H2 strain of Hepatitis A virus, propagated in human diploid cells (MRC-5). The 720ELISA unit refers to the antigen content as measured by enzyme-linked immunosorbent assay. It is a lyophilized (freeze-dried) powder requiring reconstitution. It provides active immunization against Hepatitis A virus, a significant cause of infectious hepatitis and jaundice in India, especially in areas with poor sanitation.

The vaccine contains live Hepatitis A virus (H2 strain) that has been attenuated (weakened) to lose its pathogenicity but retain its immunogenicity. Upon intramuscular administration, the attenuated virus is taken up by antigen-presenting cells. It undergoes limited replication, presenting viral antigens to the immune system. This stimulates a robust humoral (B-cell) and cellular (T-cell) immune response, leading to the production of neutralizing anti-HAV antibodies (mainly IgG) and memory B & T cells.