What is BCG vaccine: BCG vaccine is a non-toxic live bacterium vaccine. 1908 French internist A. Calmett and veterinarian C. Guerin took a very virulent strain of bovine tuberculosis and passed it on in culture. 13 years and 230 generations later, a non-pathogenic strain was obtained, but the immunity to tuberculosis remained high and could be used for vaccination against tuberculosis, especially for the prevention of childhood cornea tuberculosis and tuberculous meningitis in children. Why should newborns receive BCG vaccination? Newborns have poor resistance to various diseases, and once infected with the tuberculosis bacillus, they are susceptible to hematogenous dissemination, leading to cornual tuberculosis and tuberculous meningitis, the two most serious forms of tuberculosis with the highest mortality rate. BCG vaccine can prevent the hematogenous spread of TB bacilli, so infants can usually be vaccinated with BCG at 24 hours of birth as long as they are developing normally. However, BCG vaccination does not reduce the rate of infection in the population, but only reduces the chance of blood-borne transmission of TB bacteria when a person is infected. Abnormal reactions and complications following BCG vaccination: Abnormal reactions: (1) Local abscess or ulcer: If a local abscess has formed, the pus can be extracted with a syringe, and if an ulcer has formed (most of them last more than 6 months), a nail violet solution can be applied to make the ulcer dry and crusted, and attention should be paid to protecting the scab and waiting for it to fall off naturally. (2) Strong reaction of lymph nodes: If the lymph nodes of the axilla on the inoculation side are enlarged more than 25px, it is a strong reaction, local hot compress can be applied 3~4 times a day, if abscess has been formed, the pus can be extracted from the injection area, generally no surgical incision is used, if ulcer has been formed, after sufficient drainage, local rifampicin or streptomycin powder can be applied. Complications: (1) keloid Do not deal with; (2) osteomyelitis Equivalent to infected bone tuberculosis, treated with surgery plus conventional anti-tuberculosis treatment. (3) Systemic BCG infection: incidence about 2/1 million, mostly with innate immunodeficiency syndrome, poor treatment and high mortality.