KEY POINTS
  • Minorities, the elderly and those with underlying health conditions are at highest risk for Covid-19.
  • Those groups are being prioritized in large clinical trials for coronavirus vaccines.
  • Moderna is slowing enrollment slightly to ensure minority representation, potentially putting it behind Pfizer.
  • "I would rather we have higher diverse participants and take one extra week," Moderna CEO Stephane Bancel said. Diversity "matters more to us than speed."

Moderna, one of the developers in the lead for a vaccine to prevent Covid-19, is slowing enrollment slightly in its large clinical trial to ensure it has sufficient representation of minorities most at risk for the disease, its chief executive said.

The trial is designed to enroll 30,000 people in the U.S. to prove the vaccine's safety and efficacy. As of Aug. 28, it had enrolled 17,458, 24% of whom are from communities of color. The company provides updates on enrollment numbers every Friday afternoon.