How Do Sputnik V, Covaxin and Covishield Work? Science Behind the Covid-19 Vaccines

Sputnik V, which shares its name with the world’s first artificial satellite made by Russia, is an adenovirus-based vaccine (more on this later) that is being used by Moscow for mass vaccination.

The adenoviruses — viruses that cause common cold — are combined with the SARS-CoV-2 (the virus that causes Covid-19) spike protein, which prompts the body to make an immune response to it, according to The BMJ paper cited above.

“The SARS-CoV-2 virus is studded with proteins that it uses to enter human cells.

These so-called spike proteins make a tempting target for potential vaccines and treatments,” a New York Times (NYT) report explained. Researchers added the gene for the coronavirus spike protein to Ad26 and Ad5, and engineered them so they could invade cells but not replicate, the report said.

For Covid-19 vaccines, this gene contains instructions on how to make a spike protein, which is found on the surface of the coronavirus.

Once a person gets the vaccine, the vector enters a cell and uses it to make spike proteins.

Covaxin, on the other hand, is an inactivated vaccine — which means that it is made up of killed coronaviruses, making it safe to be injected into the body.

“The antibodies attach to viral proteins, such as the so-called spike proteins that stud its surface,” it added.

Each participant received either two doses of the vaccine, or a placebo, which were administered 21 days apart,” The BMJ said