What is the News?
India has placed an advance order to block 300 million doses of a new Covid-19 vaccine, Corbevax from Hyderabad-based company Biological E.
About Corbevax Vaccine:
- Corbevax is a recombinant protein subunit vaccine. The vaccine is being indigenously produced by Biological E, Hyderabad-based Pharmaceutical company.
- Made up of: The Corbevax vaccine is made up of a specific part of SARS-CoV-2 — the spike protein on the virus’s surface.
- Administration of Vaccine: The vaccine will be administered in two doses. It is expected to be among the cheapest available in the country.
What are Spike Proteins?
- The members of the coronavirus family have sharp bumps that protrude from the surface of their outer envelopes. Those bumps are known as spike proteins.
- These spike proteins allow the virus to enter the cells in the body so that it can replicate and cause disease.
- However, in Corbevax Vaccine the spike protein alone is given to the body. So, 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.
- 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.
Note: The technology to inject spike protein to develop immunity against a disease is not new. It has been used previously in making hepatitis B vaccines. However, Corbevax is the first vaccine made for COVID-19 to use this technology.
Different types of Covid-19 vaccines:
Vaccines are categorised on the basis of the development process adopted by scientists. For example:
- Pfizer and Moderna vaccines developed in the US are mRNA vaccines. In this type, vaccines will carry the molecular instructions to make the protein in the body through a synthetic RNA of the virus. The host body uses this to produce the viral protein that is recognized and thereby making the body mount an immune response against the disease.
- Johnson & Johnson, Sputnik V and AstraZeneca-Oxford University vaccine is a kind of viral vector vaccine. In this type, a modified version of other viruses (for example, adenovirus) is used. The virus can enter human cells but not replicate inside. A gene for the coronavirus vaccine was added into the adenovirus DNA, allowing the vaccine to target the spike proteins that SARS-CoV-2 uses to enter human cells.
- Bharat Biotech’s Covaxin and Sinovac-CoronaVac is categorised as an inactivated vaccine. In this type, an inactivated live virus is used to create an immune response against the disease.
How is the Corbevax Vaccine different from these vaccines?
- Inactivated vaccines attempt to target the entire structure of the virus.
- On the other hand, Corbevax like the mRNA and viral vector Covid-19 vaccines targets only the spike protein but in a different way.
- Viral vectors and mRNA vaccines use a code to induce our cells to make the spike proteins against which the body has to build immunity.
- On the other hand, in the case of Corbevax is actually giving the spike protein alone.
Source: Indian Express