A risk analysis by one of Australia’s leading epidemiologists suggests that claims that COVID-19 was the result of a lab leak are “equal or more probable” than a natural outbreak.

There is still heated debate among scientists over whether the SARS-CoV-2 virus escaped from the Wuhan Institute of Virology in China at some point in late 2019.

Professor Raina MacIntyre and colleagues from the Kirby Institute at UNSW Sydney acknowledge that definitive proof of a laboratory leak may never be obtained.

“[But] the question of origin cannot be answered solely by phylogenetic analysis,” they write in a journal called Risk Analysis.