We all are aware that the vaccine for the novel coronavirus is quite far away from us as it is said that it may take 12-18 months to develop. However, even after we have vaccines, that will still not translate to mass immunisation. 

Source: huffingtonpost.in

Immunisation is a process by which a person is made immune to or resists the infectious disease. Mass immunisation aims at delivering immunisations to a large group of people at different geographical locations in a short interval of time.

Therefore, just getting a vaccine for Covid-19 isn't enough. We will need a lot of it and will need it to be available across the world for it to give mass immunisation.  

Source: www.usnews.com

The managing director of Indian Immunologicals said that the institute could be one of the first ones to prepare a Covid-19 vaccine. 

However, the next obstacle would be manufacturing it at a large scale. It is estimated that the mass production of the vaccine in adequate quantities would take at least another two years from the development of these vaccines. For a vaccine to develop here are the phases it has to go through: 

Source: drugtargetreview.com

Phase 1: A small study is conducted that examines the vaccine for safety and immune responses with different dosages.  

Source: www.aljazeera.com

Phase 2: A randomised study takes place which involves the study of hundreds of people to further evaluate the safety and effectiveness of the vaccine to ascertain the optimal dose and the vaccine schedule. For Covid-19 trials, this is expected to take 8 months.  

Source: www.nytimes.com

Phase 3: After testing it upon hundreds of people and the study seems to yield the right results, the sample size increases with over thousands of people that are examined. 

Source: techcrunch.com

Phase 4: Now, the government body reviews the new vaccines and other information necessary to the licensing application of the vaccines.  

Source: www.themoscowtimes.com

Phase 5: The last phase post approval involves the study of the effectiveness of the vaccines in the real world.