Table 1.

Current Vaccines and Key Issues Relevant to the Endgame of Polio Eradication

Endgame Issues	IPV (Salk)	OPV (Sabin)
Immunologic
Primary intestinal mucosal immunogenicity	Minimal	Present
Operational
SIA use for outbreak response	Difficult	Suitable
Production risks for containment failure	High	Low
Cost	High	Low
Adverse events
Risk of VAPP	None	Present
Risk of VDPVs	None	Present

Abbreviations: IPV, inactivated poliovirus vaccine; OPV, oral poliovirus vaccine; SIA, supplementary immunization activity; VAPP, vaccine-associated paralytic poliomyelitis; VDPV, vaccine-derived poliovirus.