Pneumococcal whole-cell and protein-based vaccines: changing the paradigm

ABSTRACT

Introduction: Epidemiologic evaluations of Streptococcus pneumoniae nasopharyngeal (NP) colonization and pneumococcal disease suggest that newer serotypes in future formulations of pneumococcal conjugate vaccines (PCVs) are needed and there may need to be continued reformulations because there are many new emerging serotypes expressed by pneumococci.

Areas covered: Mechanisms of protection by next-generation whole-cell vaccine (WCV) and/or multi-component pneumococcal purified protein vaccines (PPVs) in development for prevention of pneumococcal infections.

Expert commentary: A long-term strategy for prevention of pneumococcal disease will likely include WCV and PPVs. However these vaccines will impact disease pathogenesis in a different manner than PCVs. Prevention of pneumococcal NP colonization should not be expected, nor is it desirable because risks for NP colonization by other replacement organisms into the ecological niche vacated by all pneumococci may have consequences. The expression biology of capsule and surface protein antigens are phase dependent. Therefore, the immune response will be different and the mechanism of protection divergent. WCVs and PPVs may be alternative strategies in low income developing countries to protect against invasive disease and reduce NP carriage load.

KEYWORDS:

• Streptococcus pneumoniae
• pneumococcal conjugate vaccines
• pneumococcal whole-cell vaccine
• pneumococcal protein vaccines
• nasopharyngeal colonization
• clinical trial
• pathogenesis

Declaration of interest

M.E Pichichero has served as a consultant to Sanofi Pasteur, GlaxoSmithKline, Merck and Pfizer regarding pneumococcal vaccine development. Author and his institution have received research funding from Sanofi Pasteur, Merck and Pfizer. Author is inventor and Sanofi Pasteur is owner of a patent regarding use of pneumococcal vaccines in otitis-prone children. The author has 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.

Additional information

Funding

The manuscript was funded by a National Institute of Health grant (NIH R01 08671).