Polio endgame: the global switch from tOPV to bOPV

Area of Science:

• Global Health
• Vaccinology
• Epidemiology

Background:

• Polio cases are at an all-time low globally, with type 2 poliovirus eradicated.
• Oral polio vaccine (OPV) has been crucial but can rarely cause paralysis.
• The World Health Assembly endorsed a transition to inactivated poliovirus vaccine (IPV) in routine immunization.

Purpose of the Study:

• To detail the global synchronized switch from trivalent OPV (tOPV) to bivalent OPV (bOPV).
• To outline strategies for mitigating type 2 poliovirus outbreak risks post-withdrawal.
• To ensure continued protection against remaining poliovirus types.

Main Methods:

• A globally synchronized "switch" from tOPV to bOPV in 155 countries between April 17 and May 1, 2016.
• Implementation of risk reduction activities including pre-switch immunization campaigns.
• Stockpiling of monovalent OPV2 for outbreak response and containment of type 2 viruses.

Main Results:

• The planned global switch from tOPV to bOPV is scheduled for April-May 2016.
• Multiple strategies are in place to manage risks associated with type 2 poliovirus withdrawal.
• Enhanced surveillance and response mechanisms will be utilized.

Conclusions:

• The transition to bOPV and IPV is a critical step in polio eradication efforts.
• Careful planning and risk mitigation are essential for a successful withdrawal of type 2 OPV.
• Continued global cooperation is vital to achieve a polio-free world.