Vaccines use different mechanisms to deal with SARS-Cov-2 agent pathogens. First and foremost, coronaviruses are made up of genetic code surrounded by a coat of proteins, which trigger an immune system response in the body. 

There are currently three main types of vaccines:

• Recombinant vaccine: This vaccine is based on a recombinant receptor binding protein (RDB). It is called recombinant because the proteins injected into the body are formed from recombinant pieces of the genetic code of the virus. As these proteins enter the body, the immune system is activated, producing lymphocytes and natural antibodies that can neutralise the SARS-Cov-2 infection. Adjuvants can be added to these proteins, which is a substance that boosts the body's immunogenic response. Unlike other vaccines, this one only uses the external proteins, so they do not need to be kept frozen, making them safer, more effective and easier to deliver. These vaccines are more versatile as they can be updated for new variants of the virus.

   

• Viral vector vaccines: these vaccines introduce directly into the body the genetic code of the safe virus that cannot cause disease, but which carries "instructions" and serves as a platform for producing coronavirus proteins that can provoke an immune response. This genetic code enters the body inside a different, harmless virus called a vector, because it transports this genetic code through the body to the person's cells, which transcribe the genetic material into proteins and then develop antibodies.

   

• mRNA vaccines: These vaccines inject messenger RNA into the body, which is a copy of the virus' DNA with the information that tells the cell how to form proteins. Once the mRNA enters the body, the proteins that trigger the body's immune response are produced.

^References:

^{World Health Organisation. The different types of vaccines that exist. WHO. 2021 [Accessed September 2022]. Available from: https://www.who.int/es/news-room/feature-stories/detail/the-race-for-a-covid-19-vaccine-explained}