BCG is a vaccine against tuberculosis in children. It is a live attenuated vaccine that is usually given to newborns within 24-48 hours of birth and immunity develops within 2-3 months. Some children can have another tuberculin test performed within 3 months to 3 years, and if the tuberculin test is negative, they can be given a follow-up vaccination. After the BCG vaccination, usually in 2 weeks, a vaccination spot will be formed on the skin, and a small red spot will be formed on the vaccination site, and then gradually soften, and some small white pus sores will be formed in the middle of the softened spot, and the pus will flow after the small pus sores are destroyed, and then the scar will be formed after 1-2 minutes, and some round scars will be formed after the scar is formed, and this is the process that the BCG vaccination usually goes through. Mothers of newborns, who generally do not understand this situation, may be a little strange or scared, and there is no need to be afraid. Meanwhile, if a newborn has some contraindications at the time of vaccination, such as allergy, fever, premature birth or low weight, weighing less than 2500g, these children who are not suitable for BCG vaccination, usually wait until the situation of BCG vaccination is not allowed to occur changes, and then vaccinate within 3 months. The above is for reference only. Please refer to the doctor’s instructions for specific medication and treatment.