The United States and other countries have called for a more in-depth investigation into the origins of COVID-19.

An international mission to China earlier this year proved inconclusive.

There have been renewed questions about whether the virus occurred naturally or escaped in a lab.

Flinders University Professor of medicine Dr Nikolai Petrovsky told Gareth Parker we need a definitive answer.

“Maybe there is an animal out there carrying the virus that has transmitted it to humans,” he said.

“But after 18 months and no one finding that animal, despite intensive searching within China, it increases the possibility that it could be a lab leak.”

Press PLAY to hear why scientists want an in-depth investigation