BPSC – Combined Competitive Examination · Question 22

How do vector vaccines work to provide immunity?

By introducing a weakened or inactivated virus into the body
By directly attacking and destroying pathogens in the body
By placing the virus's genetic material in a modified version of a different virus
By entering directly into cells and enabling them to create spike proteins

Show answer & explanation

Answer: (C) By placing the virus's genetic material in a modified version of a different virus

Explanation

Viral-vector vaccines (e.g. Covishield) use a modified adenovirus to deliver the spike-protein gene.

(A) Incorrect
Wrong: that describes attenuated/inactivated vaccines.
(B) Incorrect
Wrong: vaccines do not attack pathogens directly.
(C) Correct
Correct: a harmless 'vector' virus carries the target gene into cells.
(D) Incorrect
Wrong: that describes mRNA vaccines.