Herd protection induced by pneumococcal conjugate vaccine

Why is herd protection from pneumococcal disease important? The pneumococcus is the leading cause of death in children worldwide,1 and children who die are likely to be those who are unable to access lifesaving antibiotics and pneumococcal conjugate vaccine (PCV). However, if vaccination of other children in the community stops transmission of the serotypes in the vaccine, then protection is provided to those most at risk of mortality, even if they are not given the vaccine themselves. The immunisation of infants with PCV in developed countries extends protection beyond direct protection of the immunised infants, to include children too young to be immunised,2 adults with substantial risk of pneumococcal disease such as those infected by HIV,3 and older people.