What is an advantage of using a virus as a vector in gene therapy?

• A. It can enter cells / infect cells / inject DNA into cells.
• B. It always avoids immune responses.
• C. It does not replicate in host cells.
• D. It cannot target specific cell types.

Answer: (A)

Viral vectors excel because they are naturally adept at delivering genetic material into cells. Their life cycle is built around recognizing target cells, entering them, and injecting DNA or RNA, which makes it much easier to get the therapeutic gene inside the cells that need it. This efficient delivery is the core advantage. Other statements aren’t reliable: immune responses can occur with viral vectors, so they aren’t guaranteed to be avoided; replication is often disabled for safety, but that isn’t a universal property of all vectors; and targeting specific cell types can be engineered, so it isn’t true that viral vectors cannot target.