What outbreak vaccine strategies were used to manage type 2 circulation after switch to bOPV?

• A. IPV-only approach
• B. Do nothing and monitor only
• C. Monovalent or targeted OPV vaccines such as mOPV2 to rapidly boost type 2 immunity, followed by intensified containment and surveillance
• D. Vaccines not targeting type 2

Answer: (C)

When a switch to bOPV removed type 2 from routine vaccination, stopping any ongoing type 2 transmission required a rapid, targeted boost of type 2 immunity. Monovalent OPV2 is designed specifically to induce strong mucosal immunity against type 2 poliovirus, so deploying it in outbreak responses quickly reduces intestinal infection and interrupts transmission in the affected area. This approach is paired with intensified containment to prevent further spread from vaccines or facilities and with enhanced surveillance to detect and monitor transmission and guide additional vaccination if needed. An IPV-only strategy wouldn’t rapidly curb mucosal infection or stop transmission, doing nothing allows ongoing spread, and vaccines not targeting type 2 wouldn’t address the outbreak.