Epidemiological study of hepatitis B and hepatitis C infections in Northeastern China and the beneficial effect of the vaccination strategy for hepatitis B: a cross-sectional study oleh Shishen Wang, Yuhui Tao, Yuchun Tao, Jing Jiang, Li Yan, Chong Wang, Yaxuan Ding, Jianxing Yu, Dinghui Zhao, Xiumei Chi, Xiaomei Wang, Ruihong Wu, Xiuzhu Gao, Ying Shi, Yazhe Guan, Yingchun Li, Yanli Xing, Haiyan Sun, Changhua Ta, Chao Wang, Junqi Niu, Jing Meng, Hongqin Xu