It has been six months since the novel coronavirus emerged in Wuhan, China. The global toll of confirmed cases has crossed the 13 million mark and more than 5.8 lakh people have succumbed to this deadly virus, which shows no signs of abating. However, medical experts and researchers are working round-the-clock to find a COVID-19 vaccine fit for human use, and according to data shared by the World Health Organisation, as of now, there are more than 155 vaccine candidates, and 23 of them have reached the human trial stage.
Stages of Vaccine Development
- Preclinical testing: Scientists give the vaccine to animals such as monkeys or mice to see if it produces an immune response.
- Phase I trials: The vaccine is given to a small number of people to confirm if it stimulates an immune response.
- Phase II trials: An expanded trial, where the vaccine is given to 100’s of people split into groups like children and the elderly to see how it reacts in different age groups.
- Phase III trials: The vaccine is given to 1000’s of people to see how many get infected compared to volunteers who receive a placebo.
COVID-19 Vaccines that have reached stage Phase III clinical trials
At this stage scientists give the vaccine to thousands of people to see how many get infected compared with volunteers who have received a placebo (usually saline solution). Phase III tests are randomized, and the goal is to assess whether the vaccine prevents the disease, prevents infection with the pathogen, and leads to the production of antibodies or other types of immune responses
1. CoronaVac – Developed by SinoVac, China
- This China-based biopharmaceutical company has started phase III human trials.
- Named CoronaVac, the vaccine showed favourable results in the earlier phases of the trial.
- In the earlier phase, 743 healthy volunteers, aged from 18 to 59 years old, enrolled in the trials.
- There were no severe adverse events reported in either the phase I or phase II trials.
- The phase II clinical trial results show that the vaccine induces neutralizing antibodies 14 days after the vaccination.
2. AZD1222 – Developed by University of Oxford / AstraZeneca, USA
- The University of Oxford’s potential COVID-19 vaccine that has been licensed to AstraZeneca is in the Phase III trials.
- Though the company did not release the results from the earlier phases, a developer of the vaccine has said they were encouraged by the immune response from trials, and hope to publish the results by the end of July.
3. MRNA-1273 – Developed by Moderna/ National Institute of Allergy and Infectious Diseases (NIAID), USA
- This American Biotechnology company focussed on drug discovery and development has also started Phase III trials of their coronavirus vaccine.
- In the earlier phases, participants who received the initial doses were evaluated at pre-specified timepoints, and the data reaffirmed that the vaccine induced a rapid and strong immune response against SARS-CoV-2.
COVID-19 Vaccines that have reached Phase II Trials
At this stage, the vaccine is given to 100s of people split into groups such as children and the elderly to see how it reacts in different age groups. These trials are random and include a placebo group. The goals of Phase II testing is to study the vaccine’s safety, immunogenicity, proposed doses, and method of delivery.
AD5-nCoV– Developed by CanSino Biologics in Wuhan, China
COVID-19 Vaccines that have reached Phase I Trials
A safety assessing stage, where the vaccine is given to a small number of people (20-80) to confirm if it stimulates an immune response. The goals of Phase 1 testing are to assess the safety of the vaccine and to determine the type and extent of the immune response that the vaccine provokes.
1. Adjuvant recombinant – Developed by Anhui Zhifei Longcom Biopharmaceutical, Institute of Microbiology, Chinese Academy of Sciences, China
2. INO 4800 – Developed at Inovio Pharmaceuticals, Centre for Pharmaceutical Research, Kansas City, Philadelphia.
3. Inactivated vaccine – Developed by Wuhan Institute of Biological Products, Ministry of Science and Technology, China.
4. BBIBP – CorV – Developed by Beijing Institute of Biological Products, Ministry of Science and Technology, China.
5. Covaxin – Developed by Bharat Biotech, National Institute of Virology India
6. ZyCoV-D – Developed by Zydus Cadila Healthcare Limited, India
7. NVX-CoV2373 – Developed by Novavax, USA
8. BNT162 – Developed by Pfizer, BioNTech, USA.
9. AG0301-COVID19 – Developed by AnGes with Osaka University and Takara Bio, Japan
10. GX-19 – Developed by Genexine Consortium, South Korea
11. Inactivated SARs CoV2 vaccine – Developed by Chinese Academy of Medical Sciences
12. GAM-COVID-vac – Developed by Gamaleya Research Institute, Health Ministry of the Russian Federation
13. SCB-2019 – Developed by Clover Biopharmaceuticals, China
14. COVax-19 – Developed by Vaxine Pty Ltd, Australia.
15. SARS-CoV-2 Sclamp Vaccine – University of Queensland, Australia.
16. Self-amplifying RNA vaccine – Developed by the Imperial College London
17. mRNA-based vaccine – Developed by Curevac, Germany
18. SARS-CoV-2 mRNA – Developed by Walvax Biotech, China
19. Plant-based COVID-19 vaccine – Developed by Medicago Inc, Canada
(Edited by Gayatri Mishra)