Pulmonary tuberculosis skin test

At present, the vast majority of people in China are positive for PPD skin test, and it is estimated that there are more than 70% people. Positive indicates that there has been a latent infection before and there are tuberculosis antibodies in the body. PPD positive is impossible to turn negative. Tuberculosis vaccine is BCG vaccine. Now in Shanghai, babies must be vaccinated within 24 hours after birth. It is normal to vaccinate BCG, but it is abnormal not to vaccinate BCG. In fact, the employment physical examination should not require PPD to be negative, but should check that the chest film has no active lesions. I don't know why your company wants to check PPD. It doesn't seem to be in line with the actual situation, because there are too many people who are PPD positive. PPD positive doesn't mean that they have tuberculosis.