A front-runner coronavirus vaccine developed by drug giant Pfizer and German biotechnology firm BioNTech was more than 90 percent effective at protecting people compared with a placebo saline shot, according to an interim analysis by an independent data monitoring committee that met Sunday. The early look at the ongoing trial provides a decisive initial glimpse of the real-world performance of one of the four coronavirus vaccines in the last stages of testing in the US. It is the strongest signal yet that the unprecedented quest to develop a vaccine that could help bring the pandemic to an end might succeed, breaking every scientific speed record. … Pfizer, unlike its competitors, did not join Operation Warp Speed …