BCG is a vaccine used to prevent tuberculosis in infants and children, which gives them special resistance to the disease. Since the vaccine was invented by two French scholars, Kamel and Gérin, it was named “BCG” in honor of the inventors. BCG vaccine is a live, attenuated, weakly virulent vaccine. When a newborn child is vaccinated with BCG, a mild infection occurs in the body, which in turn creates the ability to resist tuberculosis without the risk of developing the disease and reduces the incidence of tuberculosis. BCG vaccination is beneficial for the healthy development of children and has a fairly obvious role in preventing TB, especially serious types of TB that can be life-threatening to children, such as tuberculous meningitis and cornual tuberculosis. Studies by the World Health Organization (WHO) have confirmed that BCG vaccination has an average efficiency of 86% in preventing TB meningitis and disseminated TB disease, 65% in preventing TB-related deaths, 64% in preventing TB meningitis deaths, and 78% in preventing disseminated TB deaths. Reactions after BCG vaccination Newborns can only see small red dot-like eyes at the vaccination site 2-3 days after vaccination, which will fade quickly and resemble normal skin in a few days. When the small pustules break down on their own, yellowish-white pus can be oozed out, at which time local ulcers are formed and scabs are formed; then pus and scabs flow again, and this is repeated many times; finally, after 2-3 months, the scabs fall off and a permanent, slightly depressed, round scar is formed. The contraindicated groups of BCG vaccine 1, suspected of having tuberculosis and suspected of having been infected by tuberculosis bacteria, should first be determined by the tuberculin test, not infected by tuberculosis bacteria, that is, negative tuberculin test, before BCG vaccination; 2, suffering from acute fever, fever, skin diseases, severe eczema, chronic diseases, acute infectious diseases and premature babies or newborns weighing less than 2,500 grams, are temporarily do not vaccinate BCG vaccine 3. People with congenital or acquired immune deficiency should never receive BCG vaccination.