Whether the BCG vaccination is successful without scarring needs to be verified by a tuberculin test, and if the tuberculin test is negative, it means that the vaccination is indeed not successful. Usually, hard nodules will appear at the vaccination site after BCG vaccination, followed by breakage of the hard nodules, scabbing and scarring, most people will leave obvious BCG scars after BCG vaccination, and a few people are successfully vaccinated even though they do not have BCG scars after vaccination. To know whether immunization is successful without scarring after BCG vaccination, you need to take a tuberculin test about one month after vaccination. If the tuberculin test is positive, it means that antibodies have been produced in the body and immunization is successful. If the tuberculin test is negative, the vaccination has failed.