"I've got an open mind on this, but I'll be clear with you - so far, the stuff I've seen does not suggest that the ... number one candidate for this is a lab leak," Johnson told CBC News chief political correspondent Rosemary Barton in an exclusive Canadian interview airing Sunday on Rosemary Barton Live.
"So the stuff I've seen suggests that at the moment, the number one suspect for the origin of this disease is still a zoonotic disease that occurred as a result of the farming of wild animals in some way."
"I'm reading a lot of interesting stuff at the moment about the possibility that there was some, you know, virus escaping from a lab. I think we've got to keep an open mind," he said.
President Joe Biden ordered aides to find answers to the origin of the virus that causes COVID-19, saying on Wednesday that U.S. intelligence agencies are pursuing rival theories potentially including the possibility of a laboratory accident in China.
Intelligence agencies are considering two likely scenarios but still lack strong confidence in their conclusions and are hotly debating which is more probable, Biden said.
The conclusions were detailed in a report to Biden, who asked his team in March to detail whether the novel coronavirus "emerged from human contact with an infected animal or from a laboratory accident," according to the president's written statement.
Biden's unusual public disclosure about private and inconclusive U.S. intelligence assessments revealed a debate raging within his administration over where the novel coronavirus originated. It also lent credence to a theory that the virus may have emerged from a Chinese research laboratory instead of in nature.