Dr. Stephen Hahn made the declaration in a video briefing with the American Medical Association. More than 5 million Americans have been infected with coronavirus, and more than 163,000 have died, according to Johns Hopkins data. Hahn acknowledged that because of the speed with which the agency is working, some experts have questioned whether the FDA will compromise its scientific principles in reviewing clinical trial data. "Let me assure you that we will not cut corners," Hahn said. "All of our decisions will continue to be based on good science and the same careful deliberative processes we have always used when reviewing medical products." Many Americans are skeptical about a vaccine. Hahn said he has seen surveys that report a significant part of the public will be reluctant to get a Covid-19 vaccine. A CNN poll in May found one-third of Americans said they would not try to get vaccinated against Covid-19, even if the vaccine is widely available and low-cost.