Covid-19 vaccine, both to meet urgent medical need and for the potential payday.Here's an update on the quest for a magic bullet against the coronavirus that has already killed more than a million people worldwide:- How many in the pipeline? - The World Health Organization (WHO) has identified 48 "candidate vaccines" at the stage of clinical trials in humans, up from 11 in mid-June.Twelve of them are at the most advanced "phase 3" stage, in which a vaccine's effectiveness is tested on a large scale, generally tens of thousands of people across several continents.Earlier this month, a US-German collaboration between Pfizer and BioNTech scored a major breakthrough by announcing the results of its phase 3 trial for its mRNA vaccine.It said the.