The B-brain vaccine is not necessarily for everyone. Encephalitis B, also known as epidemic B encephalitis virus, was once used as an extremely harmful epidemic that seriously threatened the normal growth and development of newborns in China. Transmitted by mosquitoes, Encephalitis B virus causes high fever, headache, vomiting, and a few patients will be left with brain sequelae. With the development of China’s public epidemic prevention in the last century, China’s self-developed Encephalitis B vaccine was released on the market, and China’s public epidemic prevention department adjusted the Encephalitis B vaccine to be free of charge and mandatory for newborn children. Therefore, in general, those who have been following the social vaccination program since birth will not miss the BSE vaccine. Although the vast majority of the population has been vaccinated with the BSE vaccine following the social vaccination program, not all newborns are vaccinated with the BSE vaccine due to certain reasons, such as lack of awareness of the vaccine in some remote rural areas, which may result in some newborns not being vaccinated in a timely manner.