BCG vaccination is very important for the prevention of tuberculosis. BCG vaccination, an artificial primary infection (live attenuated vaccine), enables the body to become immune to tuberculosis infection to control subsequent tuberculosis infection, thus greatly reducing the chances of occurrence of cornual tuberculosis, tuberculous meningitis and other secondary tuberculosis, and leaving no latent foci of after-effects like natural infection by tuberculosis bacteria. When should BCG vaccination be given? BCG vaccination is usually given within 24 hours after birth and is given at the site of the lateral deltoid muscle of the upper arm. The latest time for BCG vaccination is before the age of 4 years, and there is no catch-up vaccination for babies over 4 years old (including 4 years old). For babies who have not received BCG vaccination since birth, those under 3 months of age can be vaccinated directly, while those between 3 months of age and 3 years of age will be tested for tuberculin (PPD) and can be vaccinated if the result is negative, but not if the result is positive. For babies under 3 months of age who do not know if they have been vaccinated with BCG, they need to wait until they are 3 months of age to have a PPD test first, and if the result is negative, then they will be vaccinated again. Precautions for BCG vaccination of babies 1. If a newborn baby is not vaccinated with BCG in the hospital directly after birth, he or she needs to stay in the vaccination unit for 30 minutes after vaccination, during which time he or she should carefully observe whether there is any abnormal reaction and leave after ensuring that everything is normal. 2. About 2 weeks after the BCG vaccination of newborns, redness and swelling will appear at the vaccination site, followed by suppuration and formation of small ulcers. During this period, care should be taken when bathing the newborn to avoid wetting the skin of the injection site with bath water, and not to touch the pustule with your hands often to keep the area clean. The pustules produced after BCG vaccination will usually crust over at 8-12 weeks. When the scab has fallen off, a slightly depressed, round scar will form, which will be permanent. This process is a normal reaction process to BCG vaccination. 3. Newborns generally do not have systemic reactions such as fever after BCG vaccination. The abscesses that appear about 2 weeks after vaccination and the scar left after the abscesses have crusted over are normal reactions. However, if a newborn has a serious infection at the BCG vaccination site, or if pus is still flowing after 3 months, it is best to go to the hospital for treatment in a timely manner.