The statements are about vaccination programmes for the diseases cholera, measles, smallpox and tuberculosis (TB). Which one of the statements is correct for TB?
- AMost children are vaccinated before their first birthday.
- BThe pathogen has not mutated or changed its antigens.
- CThe pathogen lives in the intestine where antibodies cannot get to it.
- DThe vaccine is not effective against some strains of the pathogen.