Give scientific reasons: Hepatitis $B$ and Bird flu $DNA$ vaccines are called Recombinant $DNA$ vaccines.

(N/A) Hepatitis $B$ and Bird flu $DNA$ vaccines are called Recombinant $DNA$ vaccines because they are produced using recombinant $DNA$ technology. These vaccines consist of a small circular $DNA$ molecule (plasmid) into which a specific gene segment from the pathogen (virus) has been inserted. When this plasmid is introduced into the host,the host cells express the specific protein encoded by the pathogen's gene,which triggers an immune response without causing the actual disease.