Albert Bourla, DVM, Ph.D., Chief Executive Officer of Pfizer appears before the Senate Committee on Finance for a hearing on prescription drug pricing on Capitol Hill in Washington, DC, USA, February 26, 2019. - A Covid-19 vaccine being developed by Pfizer and Germany's BioNTech has been found to be more than 90 per cent effective, in a breakthrough that could make the shot available for use by the end of the year if drug authorities give it the green light. Photo by Chris Kleponis/CNP/ABACAPRESS.COM