Population immunity to polioviruses in the context of a large-scale wild poliovirus type 1 outbreak in Tajikistan, 2010.

•We measured anti-poliovirus (PV) antibodies among 1–24 year-olds in Tajikistan after the 2010 wild PV1 outbreak.•PV3 results used as surrogate for the pre-outbreak PV1 immunity suggest suboptimal coverage over time led to the outbreak.•PV1 seroprevalence >98% indicates mOPV1 supplementary immunization activities (SIAs) succeeded in closing the immunity gap.•PV3-susceptibility across wide age range (<90% seroprevalence in most age groups) justifies SIA age expansion to 15 years.•Widespread PV3-susceptibility supports the need for tOPV SIAs after the initial mOPV1 response.