Furthermore, published data(4) from the PCV7 era which show post-primary antibody levels at mean age 15 months (range 0.32 to 0.83 microg/mL for all but serotype 14) have declined almost to those detected in cord blood (range 0.3647 to 1.1797 microg/mL). The clinical implications of this decay in terms of memory response and duration of protection from mucosal infections, pneumonia and otitis media, are not known, however vaccine efficacy is lower for mucosal compared to invasive infection(5). Which vaccine for the booster dose?