All children should be vaccinated with BCG if they do not have an immunodeficiency disease, because BCG is effective in preventing children from having a tuberculosis infection. Infection with Mycobacterium tuberculosis can cause children to develop cornual tuberculosis, which causes persistent high fever and coughing and other symptoms that seriously affect the health of children. Before BCG vaccination, the incidence of tuberculosis was relatively high in China, and with the widespread promotion of BCG vaccination, the momentum of tuberculosis infection has now been curbed. If there is no immunodeficiency, children are to be vaccinated with BCG, but immunodeficiency diseases can cause Mycobacterium tuberculosis infection in children and cause adverse vaccination reactions.