An Overview Of Vaccine Formulation

By Shawn Hunter


Prophylactic vaccines are very vital in prevention of many of the infectious diseases in the world. Currently, only three vaccine types are in use for vaccinating human beings. The first one is the live-attenuated vaccines which have a bacterium or a virus with pathogenicity of low grade compared to the real one. The next is the inactivated ones. This is achieved by use of chemicals or heat while the subunit vaccine formulation is produced from pathogen components.

The goal of vaccinating human beings is enhancing the action to their immune system to resist infectious agents for a quite a duration. For this to be achieved there is need to add some components to the formulations. The work of these adjuvants is to increase the action of vaccines and make them stay in the body for a longer period. However, they should not cause harmful effects to the person.

On the same note, adjuvants enhance immunogenicity of the antigens in the human body. For this reason, the number of vaccine shots given is reduced and the efficacy of the vaccines in individuals with an ineffective immune system is enhanced. In addition, the elderly and the children are among the populations that receive a lot of benefits from vaccination.

There are two categories of adjuvants. The prime one is termed to as the vehicles. It consists of virosomes, mineral salts, emulsions and liposomes. Antigens incorporated inside the vaccines increase their potency. To add on this, the antigens are released in controlled amounts so that the immune system responsiveness is enhanced.

The other class consists of stimulants of immune system. They include agonists, toll-like receptors and MPLs. They work to enhance the function of immune system and increase its responsiveness to antigens which do not belong to the body. They are known to affect the level at which cytokines are produced through activation of intracellular pathways of signaling, MHC molecules and co-stimulatory signals.

Adjuvants which have been cleared to be used in human beings include virus-like particles, MPLs and immune-potentiating virosome of influenza which has been reconstituted. In addition, a combination of the MPLs and alum is accepted to be used in vaccines developed for human papilloma virus and the hepatitis viruses in some parts of the world.

Use of formulations which have immune-potentiating properties has increased the effectives of many of these vaccines in use in the present including those used for protection against cancer, influenza and hepatitis viruses. By the virtue of crucial role of T cells in regulation of immune responses, adjuvants which can enhance and modulate T lymphocytes in the cytotoxic class or cause an effect to dendritic cells by exploiting TLR are preferred. This is because they offer a more coherent approach in designing vaccines based on their ability to bring about the most efficient immune response.

From research studies centering on thisformulation, it has been recommended that new types of adjuvants be developed. This is due to the fact that the ones in current use do fail to bring about an immune response at times. The situation is even worse for the vulnerable population which includes the elderly, children and those immunocomprised. Be adequately informed on the subject. More research on the same is advised.




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