Glycoconjugate vaccines.

INTRODUCTION: The global disease burden of serious bacterial infections is caused mainly by Haemophilus influenzae type b (Hib), Streptococcus pneumoniae and Neisseria meningitidis. Death or disability may be the potential aftermath of invasive infections with these pathogens. Active immunisation is the only rational approach in preventing such infections. AREAS COVERED: This review discusses the immunology of vaccination and describes the immunogenicity, safety and impact of glycoconjugate vaccines that have been developed against Hib, the most prevalent serotypes of S. pneumoniae and N. meningitidis serogroups A, C, W-135 and Y in all ages. The immune response to the plain polysaccharide vaccines that target the same pathogens is compared to that induced by the respective glycoconjugate vaccine formulations. EXPERT OPINION: Continued surveillance is necessary to recognise any epidemiological changes influenced by the impact of glycoconjugate vaccines and is crucial in guiding future vaccination strategies. Although, in general, the immunogenicity of glycoconjugate vaccines results in robust immune responses in all ages, subsequent booster doses may be necessary to sustain protection. Challenges in addressing inequities in vaccine availability between industrialised and developing countries are still there. The limitations of plain polysaccharide vaccines make immunisation with glycoconjugates a more sustainable long term option.