FDA signals vaccine could green light early Their concern that the FDA may be moving too quickly heightened when FDA Commissioner Dr. Steven Hahn told the Financial Times that his agency could consider an emergency use authorization (EUA) for a Covid-19 vaccine before late stage clinical trials are complete if the data show strong enough evidence it would protect people. That's what happened with hydroxychloroquine and chloroquine. The FDA granted an EUA to the drugs -- much praised by President Donald Trump -- on March 28. It subsequently revoked its EUA in June after studies showed they were not effective...