The development of Covid-19 vaccines by several drug companies and academic institutions have happened at record speed, and have incorporated various vaccine technologies.
All these vaccines do their job by exposing the human body to particles or molecules that trigger an immune response, and therefore result in different levels of protection from Covid-19. Where they differ is in the method of exposure used. GAVI, the Vaccine Alliance, for example, explains that some of the methods involve trying to smuggle the antigen into the body, while others use the body's own cells to make the viral antigen.
According to the World Health Organisation, the three main approaches to creating a vaccine include: