Protein-based Vaccines

Subject – Science and Tech

Context – Indonesia’s recent approval for emergency use of the first protein-based vaccine developed by Novavax is welcome news

Concept –

Unlike the never-used-before platforms of the mRNA and viral vector vaccines, recombinant protein-based technology is time-tested and widely used for many viral diseases. Protein-based vaccines, while slow to develop, are more stable at higher temperatures, easy to scale up, highly cost-effective, safe, and efficacious.
The first protein-based vaccines relied on natural sources of antigens. In this regard, the first hepatitis B vaccine is unique in using a human source (plasma) for the vaccine antigen.

Subunit Vaccines

Rather than injecting a whole pathogen to trigger an immune response, subunit vaccines (sometimes called acellular vaccines) contain purified pieces of it, which have been specially selected for their ability to stimulate immune cells.
Because these fragments are incapable of causing disease, subunit vaccines are considered very safe.
There are several types:
- Protein subunit vaccines contain specific isolated proteins from viral or bacterial pathogens;
- Polysaccharide vaccines contain chains of sugar molecules (polysaccharides) found in the cell walls of some bacteria;
- Conjugate subunit vaccines bind a polysaccharide chain to a carrier protein to try and boost the immune response.
Only protein subunit vaccines are being developed against the virus that causes COVID-19.