The United States has approved four candidate coronavirus vaccines for clinical trials, Food and Drug Administration (FDA) chief Stephen Hahn told reporters.
“Four vaccines have been approved for clinical trials … and six more are under review,” said Hahn at a press briefing on Tuesday.
The U.S. Administration launched Operation Warp Speed, a joint health and defense project in May, which aims to deliver 300 million doses of a vaccine for COVID-19 by January 2021.
The country’s top pandemic expert, Anthony Fauci, however warned on Tuesday that there is no certainty that the United States will be able to develop a vaccine against COVID-19 that works and will be safe.
He added that vaccine effectiveness data may be available in winter or early next year.