To analyse the data about Chinese hepatitis B vaccine death cases.
From Apr 2013 to Sep 2014, the mainsteam media in China reported infant death cases following hepatitis-B vaccinations, wherein 20 cases were reported with the batch numbers. these death cases involved three companies: Shenzhen Kangtai, Dalian Hanxin and Tiantan BioTech. Chinese Food and Drug Administration started the investigation from Dec 2013 and published the investigation results twice on Jan 3rd and Jan 17th in 2014 respectively which stated that no connections found between the hepatitis B vaccines and the death cases.
From Sep 2014 to Aug 2018, no death cases following hepatitis-B injections reported by the mainstream media.
This project tries to answer below questions:
If the infant motality rates are identical regardness which company produced the injected vaccine? If the infant motality rates are identical regardness what time that the injected vaccine was produced?
自2013年4月至2014年9月，中国各主流媒体报道了婴儿注射乙肝疫苗后死亡的事件，其中20例报道中公开了疫苗的批次。报道中的死婴涉及到三家公司： 深圳康泰， 大连汉信与天坛生物。中国药监局于2014年12月启动了调查，并在2014年1月3日和2014年1月17日，中国药监局两次发出通知，认定婴儿死亡与疫苗不存在关联。
从2014年9月至2018年8月，主流媒体没有再报告类似的死婴事件。
本项目试图从数据角度回答以下三个问题：
注射不同公司生产的疫苗，婴儿死亡几率是否相同？ 注射同一公司不同时段生产的疫苗，婴儿死亡几率是否相同？