Which serotypes are present in the traditional trivalent OPV and what happened to type 2?

• A. PV1, PV2, PV3; type 2 component was removed in 2016 due to outbreaks from VDPV2.
• B. PV1, PV2 only; PV3 removed in 2016.
• C. PV2 and PV3; PV1 remained through 2016.
• D. All three remain in use today.

Answer: (A)

The main idea is how the traditional oral polio vaccine was formulated and why the type 2 component was removed. The trivalent OPV contains attenuated strains for all three poliovirus serotypes, so it includes PV1, PV2, and PV3. However, outbreaks caused by vaccine-derived type 2 poliovirus (VDPV2) led to a global decision in 2016 to remove the type 2 component from OPV. This switch moved to a bivalent OPV that covers only types 1 and 3, while protection against type 2 is maintained through the inactivated polio vaccine. That makes the statement that PV1, PV2, PV3 were present in the traditional trivalent OPV, and that the type 2 component was removed in 2016 due to VDPV2 outbreaks, the correct one.