Immunogenicity and immune persistence in 4-year-old children completing four doses of Sabin strain or wild strain inactivated poliovirus vaccine: A phase IV, open-labeled, parallel-controlled observational study

Kai Chu, Yurong Li, Dan Yu, Yu‐Fei Song, Sheng Liu, Xue Feng, Yongmei Shan, Weining Meng, Hongxing Pan