Protein conjugate polysaccharide vaccines: Challenges in development and global implementation

Abstract

Pneumonia and meningitis caused by Haemophilus influenzae type b, Streptococcus pneumoniae, and Neisseria meningitidis are among the leading causes of under five mortality and morbidity. Polysaccharide vaccines to prevent these infections are available since 1980s, but these are not effective in infants and children who are the common targets; therefore, protein conjugated were developed. The aim of this article is to understand the need for peumococcal protein conjugate vaccines, the challenges related to their development and global implementation, and the impact of these vaccines on global child health. Challenges in development of new vaccines are as follows: While pneumonia is a major threat in developing countries, available vaccine 7-valent pneumococcal conjugate vaccine (PCV7) protects against only 30% of invasive disease.Serogroup B of Neisseria meningitidis causes 32% of the cases in the USA and 45–80% or more in Europe. Due to similarity of its capsular polysaccharide with the cell surface glycoprotein on fetal brain tissue, developing a vaccine against this bacterium remains a challenge. Challenges in implementation are as follows: Replacement by nonvaccine serotypes;capsule switching;time duration of the antibody protective effect following vaccination;costs of the vaccines, programme costs, lack of knowledge of the disease burden, and targeting population groups for vaccination.

A Novel High-Potency Tetanus Vaccine

“…To expand the use of conjugate vaccine applications, other platforms are being developed, including the recombinant diphtheria toxin derivative CRM-197 ( 22 – 24 ). Additional malleable vaccine platforms are needed to expand conjugate vaccine use in the United States and globally ( 25 ).…”

Polysaccharides; Classification, Chemical Properties, and Future Perspective Applications in Fields of Pharmacology and Biological Medicine (A Review of Current Applications and Upcoming Potentialities)

“…Many vaccine formulations contain polysaccharides-based antigens such as bacterial capsular polysaccharides or tumor-associated carbohydrate antigens which have been used in many vaccines formulations [ 26 ]. Since the 80 s of the last century, polysaccharides vaccines were available for different infectious diseases like Pneumonia and meningitis [ 27 , 28 ]. Unfortunately, conventional polysaccharide antigens (mainly high-purified capsular polysaccharides) have disadvantages such as short duration with a poor immunogenic response in infants and young children because of the absence of immunological memory and IgM to IgG class switch.…”

Polysaccharide Vaccines: A Perspective on Non-Typhoidal Salmonella

“…Serogroup C (MenC) conjugate vaccine containing either tetanus toxoid or inactivated diphtheria toxin, CRM 197 , was first licensed in the United Kingdom in 1999, while a quadrivalent A, C, Y, and W135 diphtheria toxoid conjugate vaccine became first available in North America in 2005 [71]. In addition, several other vaccine candidates have been tested, including A, C, Y, and W135 antigens conjugated to tetanus toxoid or conjugated to CRM 197 [52].…”