Pneumococcal polysaccharide–protein (CRM₁₉₇) conjugate vaccines, 7- or 9-valent, in the 2 + 1 schedule

Abstract

The 7-valent pneumococcal polysaccharide–protein (CRM₁₉₇) conjugate vaccine (PCV-7) was licensed based on clinical efficacy trials using the four-dose schedule of three infant doses and a booster dose in the second year of life (3 + 1). An assessment of PCV-7 immunogenicity in studies evaluating two infant doses with a booster (2 + 1) showed similar immunogenicity for the 2 + 1 and 3 + 1 schedules, with the exception of lower post-dose two responses for serotypes 6B and 23F, compared with a three-dose primary series. The 2 + 1 PCV-7 schedule has been shown to be effective in controlling pneumococcal disease in several countries, as used in national immunization programs that are marked in particular by good uptake, compliance with the booster dose and application of a catch-up program.

Keywords::

• 2 + 1 schedule
• effectiveness
• efficacy
• heptavalent
• immunogenicity
• nonavalent
• PCV
• pneumococcal conjugate vaccine
• Prevenar
• Prevnar

Financial & competing interests disclosure

This assessment was sponsored by Wyeth, which was acquired by Pfizer Inc. in October 2009. Bernard Fritzell and Mark A Fletcher are employees of Pfizer Inc. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Writing assistance was utilized in the production of this manuscript.Medical writing support for this manuscript was provided by Vicki Schwartz, PhD, at Excerpta Medica (Bridgewater, NJ, USA) and was funded by Pfizer Inc.