Capsulate bacteria and the lung.

Capsulate bacteria cause the majority of community-acquired pneumonia presenting to hospital world-wide, at all ages. They are united by the virulence factor of their differing capsular polysaccharides, enabling them to evade phagocytosis. All cause invasive disease beyond the respiratory tract, including septicaemia and central nervous system infection. Recent advances in vaccine development have made the capsular polysaccharide an achievable target for vaccine strategies across all ages, with impacts already seen upon Streptococcus pneumoniae and Haemophilus influenzae type b pneumonia in countries able to afford these new vaccines.