Polio Vaccine Effectiveness and Duration of Protection

Vaccine Effectiveness

Two doses of inactivated polio vaccine (IPV) are 90% effective or more against paralytic polio; three doses are 99% to 100% effective.

A person is considered to be fully vaccinated if they received:

  • Four doses of any combination of IPV and trivalent oral polio vaccine (tOPV), or
  • A primary series of at least three doses of IPV or tOPV


  • The last dose in either series should be given after 4 years of age and at least 6 months after the previous dose.

Duration of Protection

It is not known how long people who received IPV will be protected against polio, but they are most likely protected for many years after a complete series of IPV. A 2009–2010 national survey showed that a high percentage of children and adults had protective antibodies against poliovirus, including adults who had received oral polio vaccine (OPV) as children decades earlier. However, adults who completed their polio vaccination series as children and are at higher risk for polio exposure can receive one lifetime IPV booster.