It says something about the stalemate in their relations that China and the United States cannot even make an exception for a pandemic that has killed millions and counting. The latest example arose in talks between senior diplomats, in which the Chinese side lashed the US approach to probes into the origins of Covid-19. The issue is American support for a World Health Organization proposal, rejected by China, for the second phase of its hunt for the origin of the coronavirus to include further investigations of the laboratory-leak theory, and audits of relevant laboratories and research institutions. This targets the Institute of Virology in Wuhan , the Chinese city at the geographical centre of the initial mass outbreak. The city was the focus of the first phase of the hunt for the origins. But the first WHO mission said the lab-leak theory was extremely unlikely, and that it was more plausible that the virus jumped from one animal species such as bats to another and then to humans. Both lines of inquiry should be exhausted. Given the political sensitivity and the urgency, it might have made more sense to have negotiated access for the lab-leak inquiry separately so as to expedite further investigation of animal transmission. China vs the WHO: where to look next in the hunt for Covid-19’s origins Six of China’s top health specialists and officials have argued that the next phase of the search for the origins of the coronavirus should extend around the world, including the US. There are indeed reports, albeit conflicting and in need of further confirmation, of pockets of the virus in Europe ahead of the Wuhan outbreak. And the wild animal trade in Asia is not confined to China. The science is not clear. Moreover scientists hold different views. But a proper scientific approach must guide the search. To establish a result with the greatest scientific probability and credibility with diverse interests, no avenue of inquiry should be left unexplored. The need to establish the origins of Covid-19 is paramount to effective global health and disease prevention strategies. The WHO has a key role. But because it is subordinate to the sovereignty of its members, it depends on cooperation among them to maintain the independence and freedom from influence that is fundamental to performance of its mission.