Table 1.

Different platforms used to develop vaccines for SARS-CoV-2. For each platform, advantages and limitations are also reported.

Platform	Development	Advantages	Limitations
Inactivated vaccine	Chemically inactivated virus	Stable; immune response targeting the Spike protein and other components of the virus	Integrity of the immunogenic particles must be maintained
Live attenuated vaccine	Genetically weakened versions of the wild-type virus	Stimulate humoral and cellular immunity to multiple components of the whole attenuated virus	Reversion to or recombination with the wild-type virus (nucleotide substitution during viral replication)
Recombinant protein vaccines	Composed of viral proteins that have been expressed in one of various systems	Safe; no live components of the virus	Memory is to be tested
Viral vector vaccine	Replication-incompetent or replication-competent viral vector expressing the target viral protein	Robust immune response	Potential integration of the viral genome into the host genome
DNA vaccine	Plasmid DNA that contain mammalian expression promotors and the target gene	High stable	Low immunogenicity
RNA vaccine	mRNA encoding for target viral proteins	No interactions with the recipient's DNA	To be maintained at very low temperatures

Legend: DNA= deoxyribonucleic acid; RNA= ribonucleic acid; mRNA=messenger ribonucleic acid.