>Two doses of inactivated polio vaccine (IPV) are 90% effective or more against polio; three doses are 99% to 100% effective.
>It is not known how long people who received IPV will be immune to poliovirus, but they are most likely protected for many years after a complete series of IPV.
https://www.cdc.gov/vaccines/vpd/polio/hcp/effectiveness-dur...