Table 1.

Advantages and disadvantages of various vaccines.

Type of Vaccine	Synthetic Long-Peptide Vaccine	DNA Vaccine	mRNA Vaccine	circRNA Vaccine
Synthesis	Synthetic long peptides	Plasmid DNA encoding the antigen	mRNA transcribed in vitro	CircRNA constructed in vitro
Advantages	Stable Safe Easy to purify Long immunization time	Stable (can be stored at room temperature) Simple production process Low cost Mass production	Fast production Low cost Cytoplasmic translation No risk of genomic integration Self-adjuvant effect	More stable and easy to store Cytoplasmic translation No risk of genomic integration Self-adjuvant effect High antigen expression efficiency
Disadvantages	Complex in vitro synthesis High cost Low immune response Potential adverse effects	Risk of genomic integration Must cross the nuclear membrane to be transcribed Carcinogenic risk	Poor stability Easily degradable Harsh storage conditions High risk of side effects	Currently not available for mass production Safety unknown
Improvement program	Use immune adjuvants	Vector and promoter optimization Improve inoculation route	Improvement of target gene expression Improve delivery system	Nucleotide modifications Improve cyclization efficiency Improve purification methods
Reference	[33,34,35]	[36,37]	[38,39,40]	[28,41,42,43]