Abstract

*Kushal Nandi, Prodipta Bhattacharyya, Sagnik Chowdhury, Suprodip Mandal, Dr. Dhrubo Jyoti Sen and Dr. Dhananjoy Saha

ABSTRACT

A COVID 19 vaccine is a vaccine intended to provide acquired immunity against COVID-19. Prior to the COVID-19 pandemic, work to develop a vaccine against the coronavirus diseases SARS and MERS had established knowledge about the structure and function of coronaviruses, which accelerated development during early 2020 of varied technology platforms for a COVID 19 vaccine. By mid-December 2020, 57 vaccine candidates were in clinical research, including 40 in Phase I–II trials and 17 in Phase II–III trials. In Phase III trials, several COVID-19 vaccines demonstrated efficacy as high as 95% in preventing symptomatic COVID-19 infections. National regulatory authorities have approved six vaccines for public use: two RNA vaccines (tozinameran from Pfizer–BioNTech and mRNA-1273 from Moderna), two conventional inactivated vaccines (BBIBP-CorV from Sinopharm and CoronaVac from Sinovac), and two viral vector vaccines (Gam-COVID-Vac from the Gamaleya Research Institute and AZD1222 from the University of Oxford and AstraZeneca).