Table 1.
Overview of the major SARS-CoV-2 vaccine strategies.
| Vaccine Type | Production | Advantages | Limitations | Total Number of Vaccines | Leading Vaccines Name (Manufacturer) | Clinical Phase | Route of Immunization * | Efficacy |
|---|---|---|---|---|---|---|---|---|
| Live-attenuated | (I) serial passage of pathogenic virus in cell culture (II) growing the virus under unfavorable conditions (III) genetically alteration via key genes |
Higher immunogenicity, strong and long-lasting immune responses | Risk of genetical instability and retrieving virulence, need for biosafety facilities | 5 | Meissa (Codagenix/Serum Institute of India) | Phase I/II | IN | - |
| Inactivated (killed) | Inactivation of the virus by heat, chemicals or radiation | Higher immunogenicity, no risk of infection | Reduced immune response, need for biosafety facilities, lower purity | 21 | Corona Vac (SinoVac) | Phase IV | IM | 50.7% |
| BBIBP-CorV (Sinopharm) | Phase III | IM | 79.3% | |||||
| BBV152 (Bharat Biotech) | Phase III | IM | - | |||||
| Vector vaccines | Non-pathogenic viral vectors delivering gene of viral antigens into the host cells | No risk of infection, no integration to host genome, strong in cellular and humoral Immune responses, fast to produce |
Pre-immunity against the vector reducing vaccine efficacy, risk of adverse reactions | 12 (Non-replicating) 6 (Replicating) |
AZD1222 (AstraZeneca) | Phase IV | IM | 70.4% |
| JNJ78436735 (Johnson & Johnson) | Phase IV | IM | 66% | |||||
| Ad5nCoV (CanSino Biologics) | Phase III | IM | 65.3% | |||||
| Sputnik V (Gamaleya Research Institute) | Phase III | IM | 91.6% | |||||
| flu-based-RBD (Jiangsu Provincial CDC) | Phase II | IN | - | |||||
| VSV-S (Israel Institute for Biological Research/ Weizmann Institute of Science) | Phase I/II | IM | - | |||||
| Protein subunit | Recombinant synthesis of whole protein or its segment | No risk of infection, no risk of genome integration, targeted immune responses | Need for some booster doses and optimal adjuvant, reduced T-cell immunity | 24 | NVX-CoV2373 (Novavax) |
Phase III | IM | 89.7% |
| ZF 2001 (Anhui Zhifei Longcom Biopharmaceutical) | Phase III | IM | - | |||||
| BP-COVID-19/KBP-201 (Kentucky Bioprocessing) | Phase III | IM | - | |||||
| DNA | plasmid vector containing a gene of antigenic protein | Stimulation of humoral and cellular responses, no risk of infection, ease of production, stability at room temperature | Need for delivery vectors, electroporation and/or adjuvants to enhance their immunogenicity | 11 | INO-4800 (Inovio Pharmaceuticals) | Phase II/III | ID | - |
| AG0301-COVID19 and AG0302-COVID19 (AnGes/Osaka University) | Phase II/III | IM | - | |||||
| ZyCoV-D (Cadila Healthcare Limited) | Phase III | ID | - | |||||
| Virus-like particle (VLP) | Empty virus particles presenting several copies of the same antigen on their surface | No risk of infection, no viral genome | Challenging development and assembly process, reduced immunogenicity, Lower purity | 2 | Medicago Inc. | Phase III | IM | - |
| SpyBiotech/Serum Institute of India | Phase II | IM | - | |||||
| mRNA | mRNA of the antigenic protein encapsulated in lipid nanoparticles | Stimulation of humoral and cellular responses, No risk of infection, ease of production, no risk of genome integration | Need for delivery vectors, unstable, need for strict cold chain for distribution and storage | 8 | BNT16b2 (Pfizer/ BioNTech) | Phase IV | IM | 95% |
| mRNA-1273 (Moderna) | Phase IV | IM | 94% | |||||
| CVnCOV (CureVac) | Phase III | IM | - |
* IM: intramuscular; IN: intranasal.