|+Summary of<unk>  types !Types !Description !Examples Protein<unk>  contains isolated proteins from pathogens (virus or bacteria) hepatitis B, acellular pertussis vaccines Polysaccharide contains chains of polysaccharides (sugar molecules) found in the pathogen's capsule such as cell walls of some bacteria pneumococcal polysaccharide vaccine, meningococcal vaccine preventing diseases from Neisseria meningitidis group A, C, W-135, and Y Conjugate contains polysaccharide chains bound to carrier proteins, such as diphtheria and tetanus toxoid, to boost the immune response pneumococcal conjugate vaccine, haemophilus influenzae type b conjugate vaccine, meningococcal conjugate vaccine Protein<unk>  A protein<unk>  is a polypeptide chain or protein molecule that assembles (or "coassembles") with other protein molecules to form a protein complex. Large assemblies of proteins such as viruses often use a small number of types of protein<unk> s as building blocks. A key step in creating a recombinant protein vaccine is the identification and isolation of a protein<unk>  from the pathogen which is likely to trigger a strong and effective immune response, without including the parts of the virus or bacterium that enable the pathogen to reproduce. Parts of the protein shell or capsid of a virus are often suitable. The goal is for the protein<unk>  to prime the immune system response by mimicking the appearance but not the action of the pathogen. Another protein-based approach involves self‐assembly of multiple protein<unk> s into a Virus-like particle (VLP) or nanoparticle. The purpose of increasing the vaccine's surface similarity to a whole virus particle (but not its ability to spread) is to trigger a stronger immune response. Protein<unk> s are generally made through protein production, manipulating the gene expression of an organism so that it expresses large amounts of a recombinant gene. A variety of approaches can be used for development depending on the vaccine involved. Yeast, baculovirus, or mammalian cell cultures can be used to produce large amounts of proteins in vitro. Protein-based vaccines are currently in use for hepatitis B and for human papillomavirus (HPV). The approach is being used to try to develop vaccines for difficult-to-vaccinate-against viruses such as ebolavirus and HIV. Protein-based vaccines for COVID-19 tend to target either its spike protein or its receptor binding domain. As of 2021, the most researched vaccine platform for COVID-19 worldwide was reported to be recombinant protein<unk> s. Polysaccharide<unk>  Vi capsular polysaccharide vaccine (ViCPS) against typhoid caused by the Typhi serotype of Salmonella enterica. Instead of being a protein, the Vi antigen is a bacterial capsule polysacchide, made up of a long sugar chain linked to a lipid. Capsular vaccines like ViCPS tend to be weak at eliciting immune responses in children. Making a conjugate vaccine by linking the polysacchide with a toxoid increases the efficacy. Conjugate vaccine A conjugate vaccine is a type of vaccine which combines a weak antigen with a strong antigen as a carrier so that the immune system has a stronger response to the weak antigen. Peptide<unk>  A peptide-based<unk>  employs a peptide instead of a full protein.
Subunit vaccine
Conjugate vaccine
Synthetic vaccine
Attenuated vaccine
Inactivated vaccine
Heterologous vaccine
Cell-based vaccine
Genetically modified vaccine