More than one billion vaccines are given to Chinese people every year, but for every life they help save from disease - the dreaded jab also harms more than 1,000 children, according to the Chinese Center for Disease Control and Prevention.
Those harmed children suffer from vaccine sequela, meaning a condition or event which can be anything from nerve damage to death.
Most countries have online reporting systems, but in China everyone agrees more can be done to improve the country's vaccination system.
Wang Yu, director of CCDCP, said there are advanced vaccine technologies and some other countries are using them. But China's vaccine technology is upgraded very slowly or not at all. China is still using vaccine production techniques from 30 years ago.
Peking University Professor Wang Yuedan blames a lack of talent. "The main disparity is in talent. There has been serious talent drainage in the field of immunology due to low pay and career development. Immunology is the core area in biomedicine and the West keeps their vaccine technology secret from us. If we don't change the system, the talent will continue to drain and there will be no substantial improvements in this field."
Li Baoxiang, whose son was left paralyzed after a H1N1 flu vaccine in Linyi city, Shandong province, wrote, "the needle of the vaccine landed on our family like a nuclear bomb and destroyed our children and our family… Since no country can ensure the vaccine is 100 percent safe, there should be an effective aid system for those who suffer adverse reactions."
The Southern Metropolis Daily spent three years following nearly 50 families with similar cases. The following are some of their stories.