The ongoing situation of COVID-19 pandemic entails us towards the
development of a prophylactic vaccine as a public health priority. The emergence of
SARS-CoV-2 in Wuhan, China during December 2019 marked the third introduction
of a highly pathogenic Coronavirus into human population in the twenty-first century.
Knowledge from the former vaccine candidates of SARS-CoV and MERS-CoV has
unlocked the door for the developers to accelerate the global vaccine development
pathway for ongoing COVID-19 pandemic, soon after the online publication of SARSCoV-
2 genomic sequence. The vaccine development pipeline for COVID-19 shows a
promising result by utilizing various platforms (nucleic acid, viral vector, recombinant
protein, live attenuated viruses, inactivated viruses and virus like particles) with
different strategies. Surprisingly till now, we have about 190 vaccine candidates in the
clinical and pre-clinical pipeline till 31st August 2020. Approximately, 39 of these
vaccine candidates are impending into the human clinical trials after showing
significant safety data in preclinical studies of which, 8 vaccine candidates are running
in final phase3 stage. Three of them have got an emergency approval for limited or
early use. At least 8 candidate vaccines have been developed from India, from which 2
of them have entered phase2 trials. Already existing tuberculosis vaccines are also
being tested in clinical trials bridging the gap before a potential COVID-19 vaccine is
developed. This chapter highlights the obstacles for implementation of vaccine
development for SARS-CoV-2. One of the impediments is identification of high-risk
population including frontline health care workers, elderly individuals and persons with
pre-existing chronic diseases. We have also provided a comprehensive overview about the COVID-19 vaccine candidates that are in preclinical and clinical stages of
development. Thus, fast track clinical trials of many candidates are implemented in
different geographical regions promising a prophylactic vaccine against SARS-CoV-2.
Keywords: COVID-19, Clinical trial, Clinical pipeline, Challenges, SARS CoV-
2, Pre-clinical trial, Vaccine development.
