April 24, 2024
Conjugate Vaccines

Empowering Immunity: The Science Behind Conjugate Vaccines

Conjugate vaccines are a specific type of vaccine that helps boost the immune response against certain bacteria. By combining the bacterium’s carbohydrate coat or capsule with a protein, conjugate vaccines allow the immune system to better identify and remember the bacterium. This enhanced memory helps the body fight off future infections more effectively through quick antibody production.

How do Conjugate Vaccines Work?

Conjugate vaccines work by combining the target bacterium’s polysaccharide coat with a protein to produce an immune response. On their own, polysaccharides do not effectively stimulate the immune system. By attaching or “conjugating” these sugars to a protein, the immune system is able recognize the polysaccharide as foreign.

When the conjugated vaccine is administered, the body’s B cells identify the attached protein and mount both a polysaccharide-specific and protein-specific immune response. This results in the generation of antibodies against both components. The attached protein helps the immune system remember the polysaccharide component for the long term through memory B cells. This memory allows for a swift response if the individual encounters the bacteria in the future.

Diseases Targeted by Conjugate Vaccines

Some of the major diseases that Conjugate Vaccines target include:

Pneumococcal Disease – Caused by Streptococcus pneumoniae bacteria, pneumococcal disease can cause pneumonia, meningitis, and bacteremia. The pneumococcal conjugate vaccine protects against 13-15 serotypes responsible for the majority of disease.

Meningococcal Disease – Neisseria meningitidis bacteria can cause meningitis and sepsis. Conjugate vaccines targeting serogroups A, C, W, and Y are available to prevent various strains of this disease.

Haemophilus influenzae Type b (Hib) – This bacterium is a leading cause of bacterial meningitis among children under 5 years old. The Hib conjugate vaccine has led to a significant reduction in disease incidence in vaccinated countries.

Typhoid Fever – Caused by Salmonella Typhi, typhoid fever remains prevalent in some developing regions. An oral typhoid conjugate vaccine has recently been prequalified by WHO.

The Impact of Conjugate Vaccines

The introduction of Conjugate Vaccines has greatly reduced the global burden of several previously prevalent bacterial diseases. Some of the notable impacts include:

– Pneumococcal conjugate vaccine has reduced invasive pneumococcal disease by over 95% in children under 2 years old in the USA after its 2000 introduction.

– Rates of Hib meningitis and epiglottitis declined over 99% in the USA following universal childhood vaccination programs in the 1990s.

– Meningococcal serogroup C conjugate vaccination programs across Europe and Australia led to dramatic reductions in serogroup C meningococcal cases within a few years.

– Pilot typhoid vaccination programs involving conjugate vaccines have shown promise for controlling endemic typhoid fever in regions like South Asia.

Ongoing Research and Development

Research into novel conjugate vaccines continues to expand protection against more strains and serotypes of disease-causing bacteria. Some ongoing areas of research include:

– Multivalent Pneumococcal Conjugate Vaccines – Adding more serotypes for broader coverage against pneumococcal diseases.

– Malaria and Tuberculosis Conjugate Vaccines – Attempting to generate protective immune responses against complex parasitic and mycobacterial diseases.

– Staphylococcus aureus and Group B Streptococcus Conjugates – Targeting serious antibiotic-resistant bacteria through new conjugate approaches.

– Plant-Based Conjugate Vaccine Production – Investigating plant systems like tobacco and soy for carbohydrate conjugate expression.

1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it