Bridging phase 2 and phase 3 pneumococcal immunologic data for future combination vaccines

Pneumococcal conjugate vaccines (PncCs) will be introduced into childhood v accination programs now that the first PncC has been licensed for use. The next generation of PncCs and possible combination vaccines containing PncC will most probably be approved on the basis of phase 2 immunogenicity and s afety data. PncCs are combination vaccines that include, at present, 7-11 c omponents. Immune response to different components may vary. Furthermore, t here seem to be population-based differences in immune response. Whether th ese differences are due to the other vaccines that are given simultaneously or due to the genetic background remains to be seen. Immune response can b e evaluated by determining both the quantity and the quality of antibodies after vaccination. However, data are still missing on the minimal protectiv e immune response and serologic correlates or surrogates of protection.