The trivalent oral polio vaccine has transitioned to the bivalent oral polio vaccine only to be replaced by a trivalent inactivated polio virus to "protect against" vaccine-induced type 2 poliovirus. - GreenMedInfo Summary
The Immunogenicity of Fractional Intradermal Doses of the Inactivated Poliovirus Vaccine Is Associated With the Size of the Intradermal Fluid Bleb.
Clin Infect Dis. 2017 Sep 1 ;65(5):851-854. PMID: 28444156
Jack Bibby
The immunogenicity of fractional (one-fifth, 0.1 mL) intradermal doses of the inactivated poliovirus vaccine (ID fIPV) is positively correlated with the size of the intradermal fluid bleb. Training of vaccinators for campaign and routine ID fIPV administration should focus on generating an 8- to 10-mm bleb with each injection. Clinical Trials Registration NCT01847872.