The failure of immunization coverage is the primary reason for the transmission and the spread of the diseases in young infants not eligible for vaccination because of age and in immunocompromised individuals. In both these categories measles, pertussis and varicella could be devastating. Pertussis, measles and varicella in the first year of life are responsible to the ED admission, the hospitalization and, exceptionally, the death. The only way to protect very young infants and immunocompromised individuals is to obtain the adequate coverage in all the population.