Why have many countries switched from OPV to IPV in vaccination efforts?

• A. To reduce the risk of VAPP and ensure safer vaccination practices
• B. To increase intestinal immunity
• C. To reduce vaccine costs only
• D. To eliminate vaccination entirely

Answer: (A)

The main idea is safety in vaccination. OPV uses a live, attenuated virus, which can rarely mutate back to a form that causes paralysis—vaccine-associated paralytic poliomyelitis (VAPP). IPV uses an inactivated virus, so it cannot replicate or revert, eliminating the risk of VAPP. As polio incidence falls, prioritizing a vaccine with no risk of VAPP becomes more important, even though OPV can confer stronger intestinal (m mucosal) immunity. So switching to IPV reduces the risk of VAPP and leads to safer vaccination practices overall. (Increasing intestinal immunity is a feature of OPV, not IPV; cost and the idea of eliminating vaccination aren’t the primary drivers.)