Booster Dose: Corbevax
The government of India announced that those who have received Covishield or Covaxin as their first or second dose for Covid-19 can take Corbevax as the third booster shot.
- Corbevax is still awaiting World Health Organisation’s Emergency Use Listing (EUL).
- Until now, the third dose had to be the same vaccine that was used for the first and second doses.
- The decision comes after India’s drug regulator approved Corbevax as a heterologous Covid booster dose for individuals aged 18 years.
- Corbevax is India’s first indigenously developed Receptor Binding Domain (RBD) protein sub-unit vaccine against Covid, with two doses scheduled 28 days apart.
- It can be stored at 2-8 degrees Celsius, which is best suited for India’s requirements.
- Corbevax is a “recombinant protein sub-unit” vaccine, which means it is made up of a specific part of SARS-CoV-2: the spike protein on the virus’s surface.
- The spike protein allows the virus to enter the cells in the body so that it can replicate and cause disease.
- However, when this protein alone is given to the body, it is not expected to be harmful as the rest of the virus is absent.
- The body is expected to develop an immune response against the injected spike protein.
- Once the human immune system recognises the protein, it produces antibodies as white blood cells to fight the infection.
- Therefore, when the real virus attempts to infect the body, it will already have an immune response ready that will make it unlikely for the person to fall severely ill.
