Abstract
The pandemic declaration of Covid-19 disease by World Health Organization (WHO) and subsequent widespread morbidities and mortalities in almost all countries of the world led to the research and development to find out a vaccine against SARS-CoV2 virus. Normally any new vaccine development takes 10-15 y time but the search for vaccine against SARS-CoV2 is going on at a very fast pace resulting in almost breakthrough in vaccine development by several research institutions and vaccine manufacturers. In pandemic situation, however, the entire process of vaccine development including clinical trials gets shortened and may be fast tracked to 15-18 mo time. It is expected that there shall be simultaneous marketing of several vaccines by the beginning of 2021. There are more than 164 candidate vaccines which are in the process of development and among them 24 vaccines are in advanced stages of development. This review aims at highlighting the present stages of development of vaccines and discussing the challenges that may be faced with these novel vaccines.