Developing a vaccine generally involves years of research. First, we need a vaccine candidate that is evaluated in animals for its safety and efficacy. After a vaccine candidate passes a pre- clinical trial, it enters the clinical trial phase. While scientists have worked round the clock in the laboratory, even regulatory approvals which used to take several months have been fast tracked. It helped eliminate all the time lapses between the pre-clinical and clinical trial stages. Earlier, the vaccine development involved a series of steps, but in the case of the coronavirus vaccine, the scientists and regulators worked in tandem, accelerating the whole process without compromises on any protocols and any step.
We are passing through COVID-19 pandemic. COVID-19 has caused social disruption, economic downturn and a significant number of deaths. To control this pandemic, the society as well as the system may have to take steps which may also be termed as drastic. Both pre-clinical and clinical data (complete data for Phase I and II, and partial data for Phase III) of Covaxin have been thoroughly scrutinized by the regulators. This data shows that the vaccine is safe and induces a robust antibody response. However, to what extent the vaccine will protect the recipients from getting the disease is not fully known yet. Therefore, the regulators have allowed its use in trial mode.
Both the Indian COVID-19 vaccines have completed their Phase I & II trials. Covishield® has completed its Phase III trials in the UK and the bridging trial in India. Covishield® has also been approved for use in 40 other countries while Covaxin® has been approved in 9.
Vaccine trial phases includes:
- Pre-clinical: Vaccine development in laboratory animals
- Phase 1 Clinical trial (small number of participants): Assess vaccine safety, immune response and determine right dosage (short duration)
- Phase 2 Clinical trial (few hundred participants): Assess safety and the ability of the vaccine to generate an immune response (short duration)
- Phase 3 Clinical trial (thousands of participants): Determine vaccine effectiveness against the disease and safety in a larger group of people (duration 1-2 years)
Source: Covid-19 Vaccine Tracker
Composition of Covishield® includes inactivated adenovirus with segments of Coronavirus, Aluminium Hydroxide Gel, L-Histidine, L-Histidine Hydrochloride Monohydrate, Magnesium Chloride Hexahydrate, Polysorbate 80, Ethanol, Sucrose, Sodium Chloride, and Disodium Edetate Dihydrate (EDTA).
Composition of Covaxin® includes inactivated Coronavirus, Aluminum Hydroxide Gel, TLR 7/8 Agonist, 2-Phenoxyethanol and Phosphate Buffered Saline [NKA1].
The active components of Sputnik V® are a modified replication-defective adenovirus of a different serotype (Serotype 26 for the first component and serotype 5 for the second), modified to include the protein S-expressing gene of SARS-CoV-2. The other ingredients include Tris-(hydroxymethyl)-aminomethane, Sodium chloride, Sucrose, Magnesium chloride hexahydrate, Disodium EDTA dihydrate, Polysorbate 80, Ethanol, and Water.