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.. … many questions remain, including whether the vaccine can prevent severe disease or complications, how long it will protect against infection and how well it will work in the elderly. They noted that required safety data will not be available until later this month. In addition, Pfizer and BioNTech have yet to submit their data for peer review by other scientists, a key step in determining the quality of the results.