The hepatitis B vaccine now in use is made by
- A. killing whole hepatitis B viruses with formalin
- B. growing the virus in chick embryos
- C. collecting antibodies from recovered patients
- D. inserting the gene for a viral surface protein into yeast, which then makes that protein
Explanation
Only the surface antigen is produced, so the vaccine can provoke an immune response with no possibility of causing the disease and with no need to handle live virus. Vaccines of this kind are called subunit or recombinant vaccines. Collecting antibodies from recovered patients would give passive immunity for a few weeks, which is treatment rather than vaccination.
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