Covid-19: How do inactivated vaccines work?

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INACTIVATED vaccines use a pathogen that has been modified so that it cannot replicate to stimulate our immune system. They are safe because they cannot cause disease. However, booster doses may be necessary.

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Vaccines that make use of the entire pathogenic virus are called whole virus vaccines. Using a pathogen or a part of a pathogen in a vaccine is a traditional approach, and most vaccines available today work this way.

In contrast, the Covid-19 mRNA vaccines by Pfizer-BioNTech and Moderna use genetic material that is chemically synthesized in a laboratory to teach our immune system how to fight off future infections with the SARS-CoV-2 virus.

There are two different types of whole virus vaccines: live attenuated and inactivated.
Live attenuated vaccines use a weakened form of a pathogen. These elicit strong immune responses but are not suitable for people with a weakened immune system.
In an inactivated vaccine, the pathogen is killed or modified in such a way that it is unable to replicate. It cannot cause disease and is, therefore, suitable for those with a compromised immune system.

The inactivation step usually involves heat, radiation, or chemicals to destroy the pathogen’s genetic material, which stops it from replicating.
Inactivated vaccines can trigger a strong immune reaction, but it is usually not as strong as the reaction that live attenuated vaccines can produce. Due to this, a person may need booster shots to ensure ongoing protection.
The Covid-19 vaccines that Sinovac, Sinopharm, and Bharat Biotech have developed are inactivated vacci-nes.

Other examples of inactivated vaccines include those against polio, hepatitis A, and rabies.
The Chinese state-owned biopharmaceutical company Sinopharm developed the inactivated Covid-19 vaccine called BBIBP-CorV in collaboration with the Beijing Institute of Biological Products.

The researchers studied SARS-CoV-2 samples from three people and chose one as the basis for their vaccine. They expanded the virus in cells and then used a chemical called beta-propiolactone to inactivate it. This chemical modifies the virus’s genetic material, leaving it unable to replicate.