WASHINGTON—The Food and Drug Administration released guidance Tuesday outlining conditions for approving a Covid-19 vaccine, including that any vaccine be at least 50% more effective than a placebo in preventing the disease. That 50% benchmark is used routinely for flu vaccines. The FDA said it wouldn’t approve—or give emergency-use authorization—to any coronavirus vaccine unless the maker had clearly demonstrated proof of its safety and effectiveness in a clinical study.

Source: Wall Street Journal June 30, 2020 11:24 UTC