Scientists on Monday said initial trial results for Pfizer Inc and BioNTech's coronavirus vaccine far outpaced their expectations for protection against a completely new disease, but that many questions remain unanswered. The drugmakers said their vaccine was more than 90 percent effective at preventing COVID-19, based on data from the first 94 people in the trial to become infected with the coronavirus. The 44,000-volunteer study was initially designed for a first interim analysis of whether the vaccine was working after 32 participants developed COVID-19.