A former top U.S. health official says he thinks the coronavirus originated in a lab in Wuhan, China, and began spreading as early as September 2019.

Robert Redfield, who led the U.S. Centers for Disease Control and Prevention during the first year of the COVID-19 pandemic, told CNN in a clip aired Friday that he thinks that scenario is more likely than any alternative, including that the virus erupted after transferring from animals to humans or in a live animal market.