TABLE 5.

Comparison between different approaches to develop SARS-CoV-2 vaccines using S protein or whole virus.

Types of vaccines	Advantages	Disadvantages
Subunit vaccines	✓ Protection against viral infection	✓ May have limited efficacy ✓ Lead to imbalanced immune response
mRNA vaccines	✓ Rapid development ✓ Low cost manufacture	✓ Cellular delivery and distribution in organs affected by properties of RNA ✓ Unknown safety among human beings
DNA vaccines	✓ Enhances humoral and cellular immune response ✓ Stable ✓ Easy to prepare and harvest in large quantity	✓ Unknown safety and efficacy for use in human beings
Vectored vaccines	✓ Can infect APCs directly ✓ Physically and genetically stable	✓ May induce poor immunity to vector
Whole virus inactivated vaccine	✓ Easy to produce ✓ Stable expression of conformational epitopes ✓	✓ Unimportant antigen may skew the immune response ✓ Need BSL3 facility for growth of pathogen