By Eva Dou & Emily Rauhala

Chinese officials on Thursday rejected a World Health Organization proposal for next steps in the search for the origins of the coronavirus, deepening questions about if and how the roots of the pandemic will be fully investigated and complicating a standoff among the WHO, China and the United States.

After a visit to Wuhan last winter, a joint Chinese-international team concluded that the virus probably jumped naturally from an animal, determined that a market linked to early cases was not necessarily the source, and all but dismissed the possibility of a lab leak.

In the months since, the methods and findings have come under intense scrutiny, including from WHO Director General Tedros Adhanom Ghebreyesus. In May, President Biden gave the U.S. intelligence community 90 days to redouble its own search and urged China to participate in a “full, transparent, evidence-based international investigation.”

But Chinese health officials on Thursday offered what may be the strongest signal yet that such an investigation is unlikely to happen on their soil, saying a WHO proposal that included audits of markets and laboratories in Wuhan was “impossible” for China to accept.

If China continues to limit — or outright blocks — outside investigators, the world will have little recourse, said Mara Pillinger, a senior associate in global health policy and governance at Georgetown University’s O’Neill Institute for National and Global Health Law.

“Without Chinese cooperation, WHO’s hands are tied, international hands are tied, and our ability to identify the origins of the virus will be much reduced.”

Tedros last week announced a five-part plan for follow-up research on the origins of the coronavirus. It called for deeper study in geographical areas that had early outbreaks, more research of animal markets in Wuhan, and audits of research labs near where the first cases emerged.

He also held a news conference at which he criticized China’s cooperation, saying the country’s government did not share “raw data” with the WHO team that visited Wuhan early this year to investigate the source of the initial outbreak.

On Thursday, Zeng Yixin, deputy head of China’s National Health Commission, fired back.

“To be honest, when I first saw the WHO’s second-phase traceability plan, I was very surprised,” he said. “Because in this plan, the hypothesis of ‘China’s violation of laboratory procedures causing virus leakage’ is one of the research priorities.

“From this point, I can feel the disrespect for common sense and the arrogant attitude toward science revealed in this plan.”

At the same Thursday news conference, Liang Wannian, head of the Chinese experts on the WHO-China team, acknowledged that certain patient data was not supplied to the foreign experts and cited China’s patient privacy regulations — repeating an assertion that has drawn skepticism from outside experts.

“Just to protect the privacy of patients, we did not agree to provide original data, nor did we allow them to copy it or take photos,” Liang said. “At that time, the international experts also fully understood this.”

The joint Chinese-international origin-tracing effort convened by the WHO has been criticized for being slow, incomplete and politicized, with holes and inaccuracies in the limited data.

The WHO said last week that it would be updating the joint report to fix “editing errors” after discrepancies came to light in the report’s profiles of early patients. A spokesman said the WHO could not resolve a discrepancy in the reported location of the first official case in Wuhan — a potentially significant detail, as it would determine whether all the earliest official cases were located near the Huanan seafood market.

The question of whether scientists should study the possibility of a lab leak remains particularly fraught.

Yuan Zhiming, a researcher from the Wuhan Institute of Virology (WIV), the main lab under scrutiny, spoke at Thursday’s news conference. He said the virus was of natural origin, calling it the “consensus in the academic community.”

Yuan said that there have been no coronavirus infections among the institute’s staff and that the institute’s high-containment P4 lab had not had any pathogen leaks or accidental infections among staff since it began operation in 2018. The institute also runs lower-security labs and conducted some of its coronavirus research in them. It has been reported that the WIV conducts some classified research and that it internally acknowledged unspecified safety lapses in November 2019.

Yanzhong Huang, a senior fellow for global health at the Council on Foreign Relations, said Chinese officials appear to be signaling Beijing’s red lines in an effort to shape the terms of reference for the next phase of the search — should it proceed.

“They are trying to be in a good negotiating position,” he said.

Beijing is also going on the offensive, lobbing unsubstantiated claims at the United States. On Wednesday, Foreign Ministry spokesman Zhao Lijian called for an investigation into the U.S. military-run infectious-disease research lab at Fort Detrick, Md., as part of coronavirus origin tracing, saying 5 million Chinese Internet users signed a petition for such a probe.

In earlier months, Beijing officials pushed the theory that the coronavirus was brought to China from overseas on frozen food packaging — a theory largely dismissed by scientists outside China because of the genetic similarity of SARS-CoV-2 to viruses previously found in bats in China.

Public health experts worry that the heated rhetoric will hurt not only the origins search but also efforts to prevent future crises.

“If all this suspicion persists, it will create a long-term barrier to cooperation in various forms,” said J. Stephen Morrison, director of the Global Health Policy Center at the Center for Strategic and International Studies.

“Having a breakdown between the U.S. and China on health security is just bad news across the board.”