Learn about Pneumonia: Facts, Figures and What You Can Do  [link fixed] 

Pneumonia Innovation Summit proceedings 2015

Preventing Pneumonia – CDC resource (USA): in the USA, pcv-13 vaccine is used initially to optimise the immunogenicity of subsequent 23-valent polysaccharide vaccine dose (Australia does not currently recommend this approach – repeat doses, 5 years apart to a maximum of three are recommended ).

Recent review of pneumococcal vaccination.  Systematic review of 23v vaccine repeat dosing – some support for impact.