Optimising the use of conjugate vaccines to prevent disease caused by Haemophilus influenzae type b, Neisseria meningitidis and Streptococcus pneumoniae.

Conjugate vaccines exist that offer protection against disease caused by Haemophilus influenzae type b (Hib), and selected serogroups/serotypes of Neisseria meningitidis and Streptococcus pneumoniae. These vaccines are not only able to prevent serious disease, but they also provide protection against asymptomatic carriage. The resulting herd immunity effects have been striking, and have played an important role in the public health success of conjugate vaccination programmes. The aim of this paper is to review the state of the current evidence on conjugate vaccines and to identify important areas for further study, in order to inform the debate regarding the best use of these vaccines.