Introduction Pneumococcal conjugate vaccines (PCVs) are designed to protect against Streptococcus pneumoniae disease. The first PCV (7-valent) was licensed based on clinical efficacy of 3 primary doses in infancy and a booster (“3p+1”). Many countries have since introduced reduced dose schedules; in 2010, 19 countries were using 2p+1 and 21 were using 3p+1 schedules. Evidence supporting the use of the 2p+1 schedule was examined in a systematic review.
Methods We searched 12 databases up to March 2010. We included randomised controlled trials (RCT) and case-control studies comparing 2p+1 to 3p+0 or 3p+1 schedules. Data on clinical outcomes, nasopharyngeal carriage and seropositivity (ELISA antibody concentration >0.35 μg/ml for all studies and serotypes) or geometric mean concentrations (GMC) were analysed.
Results There were no RCTs reporting clinical or carriage outcomes for direct comparisons between 2p+1 and 3p+0 or 3p+1 schedules. Percentages seropositive, or GMC following 2p+1 and 3p+1 schedules (3 RCTs) were similar for most serotypes, except 6B and 23F, where 3p+1 schedules were consistently favoured. GMC (1 RCT) at 13 months were substantially higher in the 2p+1 than the 3p+0 group. Differences were smaller 6 months later.
Conclusion Clinical and carriage data are absent for direct comparisons (RCTs) between 2p+1 and 3p+0 or 3p+1 schedules. Evidence supporting a 2p+1 schedule is based on limited RCT data about immunogenicity (where the correlation with protection against clinical disease is not well defined), non-randomised comparisons, or indirect comparisons of post-introduction surveillance data.
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.