Figure 1
Different stages of clinical trials for conventional vaccines by comparison with COVID-19 vaccines.
Figure 2
Adaptive immune response produced by SARS-CoV-2 (reproduced from Ref. [13] with permission). AG, antigen; APC, antigen-presenting cell; CTL, cytotoxic T-lymphocyte; IFN, interferon; IL, interleukin; MHC, major histocompatibility complex; TCR, T-cell receptor; TGF, transforming growth factor.
Figure 3
Stages of vaccine development.
Table 1
Advantages and disadvantages of various vaccine platforms, selected vaccines that have entered Phases 3 and 4, their developers, route of administration, and the number of doses required to induce the required immune response
| Vaccine platform description | Advantages | Disadvantages | Developers | Type of candidate vaccine | Route of administration | Number of doses | Phase |
|---|---|---|---|---|---|---|---|
| Inactivated virus |
|
| Sinovac Research and Development | CoronaVac; Inactivated SARS-CoV-2 COVID-19 vaccine [7, 74] | IM | 2 | 4 |
| Sinopharm + China National Biotec Group + Wuhan Institute of Biological Products | Inactivated SARS-CoV-2 COVID-19 vaccine [7, 72] | IM | 2 | 3 | |||
| Sinopharm + China National Biotec Group + Beijing Institute of Biological Products | Inactivated SARS-CoV-2 COVID-19 vaccine (Vero cells), BBIBP-CorV [7, 71, 72] | IM | 2 | 3 | |||
| Institute of Medical Biology + Chinese Academy of Medical Sciences | Inactivated SARS-CoV-2 COVID-19 vaccine (Vero cells) [7] | IM | 2 | 3 | |||
| Bharat Biotech International Limited | Whole-virion inactivated SARS-CoV-2 COVID-19 vaccine, BBV152 (Covaxin) [7] | IM | 2 | 3 | |||
| Viral vector (nonreplicating) |
|
| AstraZeneca + University of Oxford | ChAdOx1-S (AZD1222) Covishield [7, 41] | IM | 1–2 | 4 |
| CanSino Biological/Beijing Institute of Biotechnology | Recombinant COVID-19 vaccine (adenovirus type 5 vector) [7, 76] | IM | 1 | 3 | |||
| Gamaleya Research Institute; Health Ministry of the Russian Federation | Gam-COVID-Vac Adeno-based (rAd26-S + rAd5-S) [7, 74] | IM | 2 | 3 | |||
| (J&J) Janssen Pharmaceuticals | Ad26.COV2.S [7, 78, 79] | IM | 1–2 | 3 | |||
| Protein subunit |
|
| Novavax | SARS-CoV-2 rS/Matrix M1-Adjuvant (full-length recombinant SARS CoV-2 glycoprotein nanoparticle vaccine adjuvanted with matrix M) [7] | IM | 2 | 3 |
| Anhui Zhifei Longcom Biopharmaceutical + Institute of Microbiology, Chinese Academy of Sciences | Recombinant COVID-19 vaccine [7, 74] | IM | 2–3 | 3 | |||
| Sanofi Pasteur + GSK | VAT00002: COVID-19 vaccine formulation 1 with adjuvant 1 (S protein (baculovirus production) [7, 74] | IM | 2 | 3 | |||
| Instituto Finlay de Vacunas | FINLAY-FR-2 anti-SARS-CoV-2 vaccine (RBD conjugated to tetanus toxoid plus adjuvant) [7] | IM | 2 | 3 | |||
| Federal Budgetary Research Institution State Research Center of Virology and Biotechnology “Vector” | EpiVacCorona (EpiVacCorona vaccine based on peptide antigens [7] | IM | 2 | 3 | |||
| RNA based vaccine |
|
| Moderna + National Institute of Allergy and Infectious Diseases (NIAID) | mRNA-1273 [7, 79, 80, 81] | IM | 2 | 4 |
| Pfizer/BioNTech + Fosun Pharma | BNT162 [7, 79, 82, 83, 84] | IM | 2 | 4 | |||
| CureVac | CVnCoV vaccine [7] | IM | 2 | 3 | |||
| DNA-based vaccine | Zydus Cadila | COVID-19 vaccine [7] | ID | 3 | 3 |
[i] Ad5, human serotype 5 adenovirus; Ad26, human serotype 26 adenovirus; ChAd, chimpanzee adenovirus; COVID-19, severe acute respiratory syndrome (SARS) coronavirus 2 coronavirus (CoV-2) disease 2019; mRNA-1273, novel lipid nanoparticle (LNP)-encapsulated mRNA-based vaccine; IM, intramuscular; S protein, spike protein; RBD, receptor-binding domain; ID intradermal.