Table 3.

Vaccine platforms against SARS-CoV-2.

SL No.	Vaccine Technology	Principle	Advantage	Disadvantage	References
1.	mRNA-based	Delivery of modified mRNA	Scalable production Cytoplasmic No vector or foreign DNA Two or more antigens Self-amplifying mRNAs provide sustained expression Cellular and humoral responses	Stringent preparation/storage Less stable Low efficiency of delivery Transient expression (except SAM) Fortuitous immune response Cost	[27,77,156]
2.	DNA-based	Vector-based delivery of a viral gene	Easy to generate Stable Storage at room temperature Scalable Cellular and humoral responses Two or more antigens No adjuvant Ease of delivery Low cost	Issues associated with vector DNA, such as immunogenicity and genomic integration and pre-existing immunity Purity Pathogenicity due to recombination with wild-type virus	[114,157,158]
3.	Peptide-based	A fragment of whole-length viral peptide	Non-infectious Robust immune response Safe Ease of delivery	Challenging manufacturing Stability Need for adjuvant	[159,160]
4.	Live attenuated virus	De-optimization of the genome (to reduce pathogenicity)	Multiple viral antigens Strong immune response	Safety concerns Labor intensive	[157,161]
5.	Inactivated virus	Chemically or UV-inactivated virus	Relatively simple Strong immune response	Risk of partial inactivation Risk of becoming pathogenic	[92,162,163]