Delivery methods of OPV and IPV: which statement is true?

• A. OPV is given orally and IPV by injection
• B. OPV injection and IPV given orally
• C. Both are given orally
• D. Both are given by injection

Answer: (A)

The delivery methods reflect how each vaccine trains the immune system. The oral polio vaccine uses a live, weakened virus that you take by mouth, which allows it to replicate in the gut and stimulate mucosal immunity there, along with systemic antibodies. The inactivated polio vaccine uses a killed virus injected into the body, which cannot replicate and mainly induces systemic antibody responses to protect against paralytic disease.

Because of these distinct approaches, the statement that OPV is given orally and IPV by injection is the accurate one. The other options would assign the wrong route to one or both vaccines.