Pneumococcal Conjugate Vaccine Trial

A phase IV effectiveness study of pneumococcal conjugate vaccine in The Gambia.

PI: Grant Mackenzie (MRC Unit, The Gambia)
Funding: GAVI, BMGF

Following the conduct of a successful trial of a nine-valent pneumococcal conjugate vaccine (PCV) in Upper River region, the Gambian Ministry of Health introduced a seven-valent  pneumococcal conjugate vaccine (PCV7) into the routine programme of cinfant immunisation of The Gambia in August 2009. This was replaced by a 13-valent vaccine (PCV13) in may 2011. This projet was established to monitor the impact of these vaccine on the incidence of invasive pneumococcal disease and pneumonia when these vaccines were delivered through a routine immunisation programme.  Preliminary analysis of the impact of PCV7 has shown that it reduced  the incidence of  invasive pneumococcal disease caused by pneumococci of vaccine type  substantially but that this decrease has been balanced by an increase in disease caused by non-vaccine serotypes, in particular serotypes 1 and 5. Surveillance in progress will assess the impact of replacement of PCV7 with PCV13 on disease caused by these serotypes which are not represented in PCV7