Pfizer Inc said on Monday its experimental COVID-19 vaccine was more than 90% effective, a major victory in the fight against a pandemic that has killed more than a million people, battered the world's economy and upended daily life. Pfizer and German partner BioNTech SE are the first drugmakers to release successful data from a large-scale clinical trial of a coronavirus vaccine. The companies said they have so far found no serious safety concerns and expect to seek US authorization this month for emergency use of the vaccine.