Objective to understand the cause for the increase of sterile abscess cases upon DPT (whole cell) vaccination in 2005 in Beijing, so as to control the AEFI rate and improve vaccination safety.

When Yin Weidong, general manager of the vaccine developer Sinovac Biotech, established his company to develop a hepatitis A vaccine in 1992, he hadn't even heard the term 'biotech'.

Beijing Concord College of Public Health and Huang Jian, such as the view that vaccination is very important influenza prevention measures, but not the only measure.