A Synthetic Conjugate Polysaccharide Vaccine Against <i>Haemophilus influenzae</i> Type b

TLDR

Glycoconjugate vaccines provide effective prophylaxis against bacterial infections, yet no commercial vaccine has been available with key carbohydrate antigens produced synthetically. The study reports the large‑scale synthesis, pharmaceutical development, and clinical evaluation of a conjugate vaccine composed of a synthetic capsular polysaccharide antigen of Haemophilus influenzae type b. The vaccine was produced by large‑scale synthesis of the synthetic capsular polysaccharide antigen, conjugated to a carrier protein, and evaluated clinically. Clinical trials in Cuba showed long‑term protective antibody titers that compared favorably to licensed products made from bacterial Hib polysaccharide, demonstrating that synthetic complex carbohydrate‑based vaccines are feasible and provide a basis for further development against other pathogens.

Abstract

Glycoconjugate vaccines provide effective prophylaxis against bacterial infections. To date, however, no commercial vaccine has been available in which the key carbohydrate antigens are produced synthetically. We describe the large-scale synthesis, pharmaceutical development, and clinical evaluation of a conjugate vaccine composed of a synthetic capsular polysaccharide antigen of Haemophilus influenzae type b (Hib). The vaccine was evaluated in clinical trials in Cuba and showed long-term protective antibody titers that compared favorably to licensed products prepared with the Hib polysaccharide extracted from bacteria. This demonstrates that access to synthetic complex carbohydrate-based vaccines is feasible and provides a basis for further development of similar approaches for other human pathogens.