Which statement is true regarding IPV versus OPV?

• A. IPV is an injectable vaccine that induces humoral immunity but does not provide intestinal immunity, whereas OPV induces intestinal immunity
• B. IPV provides intestinal immunity only
• C. OPV provides no systemic immunity
• D. Both vaccines provide identical immunity profiles

Answer: (A)

A key distinction is how these vaccines shape immune protection: humoral immunity in the blood versus mucosal immunity in the gut. The injectable IPV uses inactivated virus and primarily drives circulating neutralizing antibodies, which protect against paralytic polio. Because it doesn’t replicate in the gut, it does not stimulate a strong intestinal mucosal response.

The oral OPV uses a live attenuated virus that replicates in the gut, tapping into the mucosal immune system and producing secretory IgA in the intestinal lining. This intestinal immunity helps block infection and reduces shedding, while it also contributes to systemic immunity.

So the statement that IPV induces humoral immunity without intestinal immunity, and OPV induces intestinal immunity, best matches how these vaccines work.