BCCL
Basically, there are two types of vaccines: first, those developed on protein-based technique, and second, developed by gene-based technique/platform. Genetic platforms are more recent than the conventional protein-based techniques. A genetic material (nucleic acid) of the virus is used to produce proteins inside the cell in the former.
They are three types of vaccines:
a) Viral vector - where a harmless virus is used to carry a gene encoding the spike protein of SARS-CoV-2.
b) DNA - the gene encoding for spike protein is inserted in a bacterium that converts in the nucleus of a cell to mRNA and forms spike protein.
c) mRNA (a messenger RNA developed in a lab to carry instruction to form spike protein without entering the nucleus of the cell.
The live attenuated vaccines contain a genetically weakened virus that replicates to a limited extent, causing no disease but inducing immune responses similar to that induced by natural infection. The protein-based vaccines include inactivated (a killed virus is used as a vaccine), protein subunit (a part of the whole virus) and virus-like particle (only outer cover/shell of the virus) vaccines.