It is possible for a child who has received the BCG vaccine to still be infected with tuberculosis.
BCG is a live attenuated vaccine that is administered within 24 hours of a child’s birth. It is an artificial way to make the body resistant to Mycobacterium tuberculosis, thus reducing the chances of a child getting tuberculosis. However, the BCG vaccine has a limited effect on inhibiting the spread of Mycobacterium tuberculosis in the population. Therefore, it is possible for children to get infected with tuberculosis after BCG vaccination.
BCG vaccine has a reliable protective effect against tuberculous meningitis and disseminated tuberculosis in children, but it does not prevent primary infection or the resurgence of latent infection in the lungs, which is the main source of Mycobacterium tuberculosis transmission in the population. Moreover, children will not all succeed in producing antibodies after BCG vaccination, and a very small number will not be immunized.
Although it is possible for a child to be infected with tuberculosis after BCG vaccination, the likelihood of this happening is extremely small, and BCG vaccination is an effective way to prevent children from contracting Mycobacterium tuberculosis. Parents are advised to immunize their children with BCG in a timely manner according to the immunization schedule.