https://www.scientificamerican.com/article/pfizers-early-results-bode-well-for-a-covid-vaccine-approval-this-year/ > After a week during which the U.S. had nearly a million new COVID cases, pharmaceutical company Pfizer and its German partner BioNTech announced on Monday that a preliminary analysis suggests their experimental vaccine is more than 90 percent effective at preventing the disease. The welcome news signifies that efforts to slow the worst pandemic in more than a century might finally be bearing fruit. > The news was reported following an early look at data on 94 cases from Pfizer’s phase III clinical trial, which has so far enrolled nearly 44,000 people. Questions remain about how long protection lasts and whether the vaccine prevents severe disease in the elderly and other vulnerable populations. Still, the preliminary results—announced in a press release—“are extremely encouraging,” says Paul Offit, a pediatrician and director of the Vaccine Education Center at the Children’s Hospital of Philadelphia. “It means that the vaccine is likely to be very effective as we look at more participants in the trial, moving forward.”