BCG vaccination is usually given within 24 hours after the baby is born, and the site of vaccination is the outer deltoid muscle of the upper arm. The BCG vaccine itself is septic and should not be touched by hand or handled in any way after the BCG vaccine is injected, no matter what it grows into. The BCG vaccine needs to suppurate and break down before it can grow into a flower. Generally, it can grow well by about 5 months. It is important to note that the septic area should not be exposed to water. About 1-2 weeks after BCG vaccination, the baby will have small red nodules, which will grow gradually and become slightly painful and itchy, but will not have a fever; 6-8 weeks, pustules or ulcers will form; 10-12 weeks, scabs will start to form, and after the scabs fall off, a small, slightly red scar will be left, and later the red color will gradually turn into skin color. Generally, local redness and infiltration, pus formation, and small ulcers appear around 2 weeks after BCG vaccination, and appropriate treatment treatment is appropriate for serious cases. When pustules appear, they can be treated according to the following methods: 1. When the abscess breaks, do not squeeze the pus with your hands or scratch off the scab, and use gentian violet solution to rub the larger break, do not use other drugs to rub it; 2. Keep the area clean and change underwear frequently to prevent infection; 3. Individual children can have swollen lymph nodes in the axilla or neck or collarbone on the same side of the vaccination, and hot compresses can be applied. If you do not see improvement, you should go to the tuberculosis control center in time and do not take care of it without permission to avoid serious consequences; 4. If the local reaction is severe or accompanied by systemic symptoms such as fever, you should go to the hospital for examination in time. The local reaction after BCG vaccination is different from other vaccines. The vast majority of children will have local reaction 3-4 weeks (initial vaccination) or 1-2 weeks (repeat vaccination) after BCG vaccination. After a process of redness, swelling, infiltration, pustule formation, rupture and crusting, the crusts usually come off in about 3 months and local scars are formed. This is a normal reaction process after BCG vaccination and is a sign of effective vaccination. If this reaction does not occur, it indicates that the vaccination has failed, and supplementary BCG vaccination should be considered.