Positive data on BioNTech and U.S. partner Pfizer Inc's COVID-19 vaccine is an unlikely success for the married couple behind the German biotech firm, who have devoted their lives to harnessing the immune system against cancer.Pfizer said on Monday said its experimental vaccine was more than 90% effective in preventing COVID-19 based on initial data from a large study. Pfizer and BioNTech are the first drugmakers to show successful data from a large-scale clinical trial of a coronavirus vaccine. From humble roots as the son of a Turkish immigrant working at a Ford factory in Cologne, BioNTech Chief Executive Ugur Sahin, 55, now figures among the 100 richest Germans, together with his wife and fellow board member Oezlem Tuereci, 53, according to weekly Welt am Sonntag.